the paleogene of the gulf of mexico and caribbean basinsthe paleogene of the gulf of mexico and...

The Paleogene of the Gulf of Mexico and Caribbean Basins: Processes, Events, and Petroleum Systems

27th Annual Gulf Coast Section SEPM FoundationBob F. Perkins Research Conference

2007

Program and Abstracts

Houston Marriott Westchase, Houston, Texas

December 2–5, 2007

Edited by

Lorcan KennanJames Pindell

Norman C. Rosen

ii Program and Abstracts

Copyright © 2007 by theGulf Coast Section SEPM Foundation

www.gcssepm.org

Published December 2007

The cost of this conference has been subsidized by generous grants from StatoilHydro and Chevron.

http://www.gcssepm.org

http://www.statoil.com

http://www.chevron.com

The Paleogene of the Gulf of Mexico and Caribbean Basins: Processes, Events, and Petroleum Systems iii

Preface

This year’s theme for the 27th Annual Bob F.Perkins Research Symposium was to examine adistinctive time period within the greater evolutionaryhistory of the Gulf of Mexico, Caribbean, and northernSouth America; the Paleogene. Within the longer-termJurassic-Recent histories of these regions, some of themost enigmatic yet crucial aspects of the petroleumsystems pertain to the Paleogene. In the Paleogene ofthe Gulf of Mexico, we have Chicxulub and its “ejectareservoirs,” the Laramide Orogeny as a proximal sourceof clastic sediment, strong climate changes and re-initiation of glacio-eustatic sea level changes, deep-water Wilcox sand and its age and correlation issues,deep water structures and their genesis, Paleogenecanyons and their causal mechanisms, Paleogenemarginal failure and re-grading of the slope, andpossible isolation from the world’s seas and water leveldraw down, to name a few. The talks, papers, anddiscussions given at this year’s conference providedone of most comprehensive examinations of theseissues made to date, thereby helping the explorationcommunity move ahead on Paleogene leads with ashared sense of enthusiasm and risk.

Papers on the Gulf of Mexico ranged from formalUSGS estimates of reserves in the Gulf’s Cenozoic(Warwick et al.; Swanson et al.); stratigraphy,sedimentology, and petrophysics of the “whopper” andother sands of the deep water Wilcox system (Zarra;Winker; Fiduk; Fillon; Matava et al.); delivery systems ofthese sands to the toe of the former slope (Pindell andKennan); discussions of the age, form, and origin of thePaleogene paleo-canyons along the Gulf’s rims(Galloway; Cossey); an update on the hypothesis ofPaleogene water level draw down in the Gulf as a resultof the Cuban collision with the Bahamas (Berman andRosenfeld); Paleogene bio- and other chrono-stratigraphies (Rosen; Denne; Ellwood et al.); structureof the Paleogene, both of Paleogene age as well asyounger structuring of the Paleogene strata (Mount etal.; Seitchik et al.; Radovich et al.); an analysis of K-Timpact generated sediments in Mexico (Grajales);exploration and appraisal challenges of the deep waterPaleogene (Stokes et al.; Lewis et al.); and the link toLaramide deformations in the supply of sediment to theGulf (Eguiluz); and thermal modelling at the Wilcox levelof the Gulf’s petroleum systems (Rowan et al.).

Turning to the Paleogene of northern SouthAmerica, reconstructing Paleogene sandstonefairways, great rivers, and the processes that controlledthem are top of the exploration checklist. Here, as withthe Gulf of Mexico, the progressive release of seismic,well, and core information is allowing a consensus to

form regarding tectonic evolution in the complexCaribbean plate boundary zone, upon whichexploration strategies may now be based more firmly.Themes included tectonostratigraphic evolution andbasin genesis (Pindell and Kennan; Gomez et al.);clastic sediment distribution systems (Vincent andWach); analyses of exploration strategy and riskreduction (Villamil; Kean et al.); and review of criteriafrom the northern Andes requiring that the CaribbeanPlate is of Pacific origin (Kennan and Pindell).

In both the Gulf of Mexico and northern SouthAmerica, these papers looked back through the veil ofNeogene evolution and examined the interrelatedelements of the region’s Paleogene geology. In sodoing, we broadened our appreciation for what it wasabout the Paleogene that made it so unique, as well asso crucial to ongoing exploration efforts.

As usual, the GCSSEPM Section and Foundationand this year’s technical committee are deeply gratefuland indebted to all the technical contributors who havedonated their time, data, and effort to give talks at theconference and papers for these transactions. This yearin particular seems to have been worse than most yearsregarding time, given the occurrence and elevatedstakes of the various license rounds. Without thesevaliant efforts by the entire cast of speakers, which Ipersonally am aware involved much weekend time, wewould lose one of the most important events of the yearon the Houston calendar.

In addition, I personally would like to thank anumber of people who played key roles in this year’smeeting and transactions. Dr. Lorcan Kennan took onmost of the daunting task of processing the manuscriptsfrom initial receipt to final submission. Lorcan did aterrific job and I hope neither he nor I caused anyoffence to anyone in our efforts to get the paperssubmitted “in time,” if not always “on time.” “Finalsubmissions” then went on to Norman Rosen, whopersonally read and standardized every paper andensured a certain level of English comprehensionacross the board. The next step was for the papers togo on to Gail Bergan, who organized them allinteractively onto this year’s CD ROM. I would also liketo thank those on the technical committee for helping tofill out the top notch technical agenda that was thisyear’s meeting; Josh Rosenfeld, Jon Blickwede, StuartLake, Tomas Villamil, Larry Zarra, and Dick Fillon.

And then there are the conference sponsors, whoare listed elsewhere on the CD. We are mostappreciative of the corporate support that we have

iv Program and Abstracts

received for this conference; these meetings would notbe possible without it.

Finally, let us not forget that the entire Gulf ofMexico exploration community owes a huge and

gracious thanks to Dr. Norman Rosen and the trustees,who share and believe in the original vision and wisdomof Bob F. Perkins and keep this fabulous annualmeeting running.

James PindellTectonic Analysis Ltd.

Sussex, England.October, 2007

The Paleogene of the Gulf of Mexico and Caribbean Basins: Processes, Events, and Petroleum Systems v

The Paleogene of the Gulf of Mexico and Caribbean Basins: Processes, Events, and Petroleum Systems

27th Annual Gulf Coast Section SEPM FoundationBob F. Perkins Research Conference

Houston Marriott WestchaseHouston, Texas

December 2–5, 2007

Program

Sunday, December 2

4:00–6:00 p.m. Registration (Grand Foyer) and Poster Setup (Grand Pavilion)6:00–8:00 p.m. Welcome Reception and Poster Preview (Grand Pavilion)

Monday, December 3

7:00 a.m. Continuous Registration (Grand Foyer)8:00 Welcome, Rashel Rosen (Chair of the Board of Trustees, GCSSEPM Foundation) (Grand Pavilion)

Session I—Monday morning: Setting and Hydrocarbon Potential of Paleogene Sands, Gulf of MexicoCo-Chairmen: Josh Rosenfeld and Lorcan Kennan

8:15 Introductory remarks, Jim Pindell8:30 Warwick, Peter D.; Coleman, James L.; Hackley, Paul C.; Hayba, Daniel O.;

Karlsen, Alexander W.; Rowan, Elisabeth L.; and Swanson, Sharon M.USGS Assessment of Undiscovered Oil and Gas Resources in Paleogene Strata of the U.S. Gulf of Mexico Coastal Plain and State Waters ..........................................................................1

9:00 Fiduk, Joseph C.; Anderson, Lynn E.; Schultz, Thomas R.; and Pulham, Andrew J.Deep-Water Depositional Trends of Mesozoic and Paleogene Strata in the Central Northern Gulf of Mexico ..............................................................................................................................2

9:30 Mount, Van; Dull, Kathy; and Mentemeier, SamStructural Style and Evolution of Traps in the Paleogene Play, Deepwater Gulf of Mexico ......4

10:00 Coffee

vi Program and Abstracts

Session I Cont.—Monday morning: Setting and Hydrocarbon Potential of Paleogene Sands, Gulf of MexicoCo-Chairmen: Lorcan Kennan and Josh Rosenfeld

Keynote Address:

10:30 Zarra, LarryChronostratigraphic Framework for the Wilcox Formation (Upper Paleocene–Lower Eocene) in the Deep-Water Gulf of Mexico: Biostratigraphy, Sequences, and Depositional Systems .....5

11:15 Pindell, James and Kennan, LorcanRift Models and the Salt-Cored Marginal Wedge in the Northern Gulf of Mexico: Implications for Deep-Water Paleogene Wilcox Deposition and Basinwide Maturation ................................6

12:00–1:15 Lunch (provided)

Session II—Monday afternoon: Paleogene Biostratigraphy and Geochronology, Gulf of MexicoCo-Chairmen: James Pindell and Art Berman

1:30 p.m. Rosen, Rashel N.Lower Paleogene Chronostratigraphy: A Review .......................................................................7

2:00 Denne, Richard A.Paleogene Calcareous Nannofossil Bioevents from the Fold Belts of the Deep-Water Central Gulf of Mexico .............................................................................................................................8

2:30 Ellwood, Brooks B.; Fillon, Richard H.; Waterman, Arthur S.; and Kassab, AhmedHigh Resolution Correlations: Projecting Global Data Sets into Gulf Coast Sedimentary Sequences Using Biostratigraphy and Magnetic Susceptibility ..................................................9

3:00 Coffee

Session III—Monday afternoon: Paleogene Canyons and Wilcox Sands: Pros and Cons of the Gulf of Mexico Draw-Down HypothesisCo-Chairmen: James Pindell and Josh Rosenfeld

Keynote Address:

3:30 Galloway, William E.Wilcox Submarine Canyons: Distribution, Attributes, Origins, and Relationship to Basinal Sands .............................................................................................................................10

4:15 Cossey, Stephen P.J.Recent Geological Understanding of the Chicontepec Erosional “Paleocanyon,” Tampico-Misantla Basin, Mexico ..............................................................................................................12

4:45 Berman, Arthur E. and Rosenfeld, Joshua H.A New Depositional Model for the Deep-Water Gulf of Mexico Wilcox Equivalent Whopper Sand—Changing the Paradigm .................................................................................................13

5:20 Open discussion on the drawdown hypothesis (Grand Pavilion)

6:30–8:30 Buffet supper (provided) and open poster sessions

The Paleogene of the Gulf of Mexico and Caribbean Basins: Processes, Events, and Petroleum Systems vii

Tuesday, December 4

Session IV—Tuesday morning: Paleogene Structural Development, Gulf of MexicoCo-Chairmen: James Pindell and Lorcan Kennan

8:20 a.m. Introductory remarks, Jim Pindell

Keynote Address:

8:30 Seitchik, Adam M.; Powell, Timothy; Sullivan, Robert; and Adams, Stephen D.Wilcox Structural Variations in Walker Ridge and Central Keathley Canyon ..........................15

9:15 Radovich, Barbara J.; Connors, Christopher D.; and Moon, JerryDeep Imaging of the Paleogene, Miocene Structure and Stratigraphy of the Western Gulf of Mexico using 2D Pre-Stack Depth Migration of Mega- Regional Onshore to Deep Water, Long-Offset Seismic Data .........................................................................................................16

9:55 Coffee

Session V—Tuesday morning: Paleogene Reservoirs and Stratigraphy, Gulf of MexicoCo-Chairmen: Lorcan Kennan and James Pindell

10:20 Matava, Tim; Radovich, Barbara; and Moon, JerrySource Rock and Reservoir Controls on Deepwater Prospectivity in the Gulf of Mexico Paleogene Play .........................................................................................................................17

10:50 Swanson, Sharon M.; Karlsen, Alexander W.; and Warwick, Peter D.USGS Assessment of Undiscovered Oil and Gas Resources for the Oligocene Frio and Anahuac Formations, U. S. Gulf of Mexico Coastal Plain and State Waters: Review of Assessment Units ........................................................................................................................18

11:20 Winker, Charles D.Paleogene Stratigraphic Revision and Tectonic Implications, Gulf of Mexico Abyssal Plain ..19

12:05–1:15 Lunch (provided)

Session VI—Tuesday afternoon: Exploration and Appraisal Challenges, Paleogene of the Gulf of MexicoCo-Chairmen: Richard Fillon and Larry Zarra

1:30 p.m. Lewis, Jennifer; Clinch, Simon; Meyer, Dave; Richards, Matt; Skirius, Christine; Stokes, Ron; and Zarra, Larry

Exploration and Appraisal Challenges in the Gulf of Mexico Deep-Water Wilcox: Part 1—Exploration Overview, Reservoir Quality, and Seismic Imaging ..............................................20

2:00 Stokes, Ron; Clinch, Simon; Meyer, Dave; Lewis, Jennifer; Richards, Matt; Skirius, Christine; and Zarra, Larry

Exploration and Appraisal Challenges in the Gulf of Mexico Deep-Water Wilcox: Part 2—Porosity, Permeability, and Producibility .................................................................................21

viii Program and Abstracts

2:30 Fillon, Richard H.Wilcox Depositional Architecture in the Gulf of Mexico Basin: A Framework for Improving Deep Water Exploration and Reservoir Risk ............................................................................22

3:00 Coffee

Session VII—Tuesday afternoon: Paleogene Tectonics and Stratigraphy, Northeast South AmericaCo-Chairmen: Tomas Villamil and Stuart Lake

3:30 Pindell, James and Kennan, LorcanCenozoic Kinematics and Dynamics of Oblique Collision Between two Convergent Plate Margins: The Caribbean-South America Collision in Eastern Venezuela, Trinidad and Barbados ....................................................................................................................................23

4:15 Vincent, Hasley and Wach, GrantPaleogene Slope Deposits; Examples from the Chaudiere, Pointe-a-Pierre and San Fernando Formations, Central Range, Trinidad ......................................................................24

4:45 Kean, Allan; Brisson, Ignacio; Preston, Chuck; Colmenares, Julio; Connolly, David;Sikora, Paul; Legarretti, Leonardo; Duddy, Ian; Pindell, James; Kennan, Lorcan; Odegard, Mark; Hossein, Hank; and Armentrout, John

Reducing Geologic Risk in Frontier Deep Water Exploration of the Paleogene, Suriname, South America ............................................................................................................................25

5:15 Adjourn

5:30 Beer, wine, snacks, and poster sessions

8:00 Authors will remove posters; contractor will start removing display boards at 8:15 p.m.

Wednesday, December 5

Session VII Cont.—Wednesday morning: Paleogene Tectonics and Stratigraphy, Northwest South AmericaCo-Chairmen: James Pindell and Tomas Villamil

8:20 a.m. Introductory remarks, Jim Pindell8:30 Gomez, Elías; Butcher, Geoff; and Stewart, Dave

Development of the Colombian Andes and Caribbean Regions at the Interface between the South American, Caribbean, and Nazca Plates .........................................................................26

9:00 Villamil, Tomas; Vásquez, César; and Bolaños, AlixDiffering Structural Trends of Oligocene and Miocene Tectonic Events, Northern Putumayo Basin, Colombia: Implications for Petroleum Exploration .......................................................27

9:30 Kennan, Lorcan and Pindell, JamesDextral Shear, Terrane Accretion and Basin Formation in the Northern Andes: Explained only by Interaction with a Pacific-Derived Caribbean Plate ....................................................28

10:00 Coffee

The Paleogene of the Gulf of Mexico and Caribbean Basins: Processes, Events, and Petroleum Systems ix

Session VIII—Wednesday morning: Peripheral Aspects of Paleogene Development, Gulf of MexicoCo-Chairmen: John Blickwede and Josh Rosenfeld

10:30 Eguiluz-de Antuñano, SamuelLaramide Deformation in the Burgos Basin, Northeastern Mexico ..........................................29

11:00 Grajales-Nishimura, J.M.Impact-Induced Sediments at the K-T Boundary: Offshore Campeche and Chiapas-Tabasco Region, Southeastern Mexico .....................................................................................................30

11:30 Rowan, E.L.; Warwick, P.D.; and Pitman, J.K.Thermal Maturation History of the Wilcox Group (Paleocene-Eocene), Texas: Results of Regional-Scale Multi-1D Modeling ...........................................................................................31

12:00 Wrap-up; concluding remarks, Jim Pindell

Poster Session OnlyChairman: Jon Blickwede

Lowrie, Allen and Jenkins, LindaMargin Tectonics: Passive Continental Margins Migrating Basinward ...................................32

Author Index ....................................................................................................................................... A-1

x Program and Abstracts

GCSSEPM Foundation

Trustees and Executive DirectorRashel N. Rosen (Chairman)Micropaleontological ConsultantHouston, Texas

Michael J. StyzenShell International E&P Inc.Houston, Louisiana

Michael J. NaultApplied BiostratigraphixHouston, Texas

Paul Weimer University of ColoradoBoulder, Colorado

Norman C. Rosen, Executive DirectorNCR & AssociatesHouston, Texas

Executive Council

PresidentKevin SchofieldBHP Billiton Petroleum (Americas) Inc.Houston, Texas

President ElectJanok P. BhattacharyaUniversity of HoustonHouston, Texas

Vice President

Christopher S. LerchBHP Billiton Petroleum (Americas) Inc.Houston, Texas

SecretaryLana CzerniakowskiConocoPhillipsHouston, Texas

TreasurerRamón TreviñoBureau of Economic GeologyAustin, Texas

Past-PresidentLesli WoodBureau of Economic GeologyAustin, Texas

Audio-Visual and Poster CommitteeMichael J. Nault (Chairman)Applied Biostratigraphix

Jon BlickwedeStatoil

Arden CallenderApplied Biostratigraphix

Program Advisory Committee Co-ChairmenJames PindellTectonic Analysis, Ltd.

Joshua RosenfeldConsultant

Jon BlickwedeStatoil

Larry ZarraChevron

Stuart LakeApache Corporation

Richard FillonEarth Studies Group

Lorcan KennanTectonic Analysis, Ltd.

Tomas VillamilCC Energy

Manuel Iturralde-VinentMuseo Nacional de Historia NaturalHabana, Cuba

The Paleogene of the Gulf of Mexico and Caribbean Basins: Processes, Events, and Petroleum Systems xi

Contributors to the GCSSEPM Foundation

Sponsorship CategoriesPlease accept an invitation from the GCSSEPM Section and Foundation to support Geological and Geophysical

Staff and Graduate Student Education in Advanced Applications of Geological Research to Practical Problems ofExploration, Production, and Development Geology.

The GCSSEPM Foundation is not part of the SEPM Foundation. In order to keep our conferences priced at a lowlevel and to provide funding for university staff projects and graduate scholarships, we must have industry support.The GCSSEPM Foundation provides several categories of sponsorship. In addition, you may specify, if you wish,that your donation be applied to Staff support, Graduate support, or support of our Conferences. Please take amoment and review our sponsor categories for 2007, as well as our current and past sponsors. In addition, we askthat you visit our sponsors’ Web sites by clicking on their logo or name. Thank you for your support.

Corporate Sponsorships

Diamond($15,000 or more)

Platinum($10,000 to $14,999)

Gold($6,000 to $9,999)

Silver($4,000 to $5,999)

Bronze($2,000 to $3,999)

Patron($1000 to $1,999)

Individuals & Sole Proprietorships

Diamond($3,000 or more)

Platinum($2,000 to $2,999)

Gold($1,000 to $1,999)

Silver($500 to $999)

Bronze($300 to $499)

Patron($100 to $299)

Sponsor AcknowledgmentFor 2007, all sponsors will be prominently acknowledged on a special page inserted in the 2007 and 2008

Conference Abstracts volume and CDs, and with large placards strategically placed throughout the meeting areasduring these conferences.

Corporate-level Diamond sponsors will be acknowledged by having their logo displayed on the back cover of thejewel case for the Conference CD. Corporate level Platinum sponsors will be acknowledged by having their logoplaced in the front matter of the Program & Abstracts volume. All contributions used for scholarships and/or grantswill be given with acknowledgment of source.

In addition to the recognition provided to our sponsors in GCSSEPM publications, we proudly provide a link toour sponsors’ Web site. Just click on their logo or name to visit respective GCSSEPM sponsors.

The GCSSEPM Foundation is a 501(c)(3) exempt organization. Contributions to it are tax deductible ascharitable gifts and contributions.

For additional information about making a donation as a sponsor or patron, please contact Dr. Norman C. Rosen,Executive Director, GCSSEPM Foundation, 2719 S. Southern Oaks Drive, Houston, TX 77068-2610. Telephone(voice or fax) 281-586-0833 or e-mail at [email protected].

mailto:[email protected]

xii Program and Abstracts

2007 Sponsors

Corporate Sponsorships

Individuals and Sole Proprietorships

Diamond

Platinum

Gold

Silver

Gold

Silver Ed Picou Michael J. Nault

Bronze Nancy Engelhardt-Moore

http://www.tectonicanalysis.com

http://www.devonenergy.com

http://www.shell.com

http://www.statoil.com

http://www.chevron.com

http://www.bhpbilliton.com

http://www.conocophillips.com

http://www.eogresources.com



The Paleogene of the Gulf of Mexico and Caribbean Basins: Processes, Events, and Petroleum Systems xiii

2006 Sponsors

Corporate SponsorshipsSilver

Patron

Individuals and Sole ProprietorshipsSilver

Michael J. Nault Nancy Engelhardt-Moore

Ed Picou

SHELL Exploration and Production Company

SHELL International Explora-tion and Production


http://www.conocophillips.com


http://bhpbilliton.com

http://www.eogresources.com

http://www.omni.com

xiv Program and Abstracts

Credits

CD ROM Design and Publishing by

Houston, Texaswww.bergan.com

Cover ImageThe cover images chosen for this year’s conference are from Denne: “Paleogene Calcareous Nannofossil

Bioevents from the Fold Belts of the Deep-Water Central Gulf of Mexico” (nannofossils, Plate 1) and Zarra:“Chronostratigraphic Framework for the Wilcox Formation (Upper Paleocene–Lower Eocene) in the Deep-WaterGulf of Mexico: Biostratigraphy, Sequences, and Depositional Systems” (core photos, Fig. 23).

http://www.bergan.com

http://www.bergan.com

The Paleogene of the Gulf of Mexico and Caribbean Basins: Processes, Events, and Petroleum Systems 1

USGS Assessment of Undiscovered Oil and Gas Resources in Paleogene Strata of the U.S. Gulf of Mexico Coastal Plain and State Waters

Warwick, Peter D.Coleman, James L.Hackley, Paul C.Hayba, Daniel O.Karlsen, Alexander W.Rowan, Elisabeth L.Swanson, Sharon M.U.S. Geological Survey956 National CenterReston, Virginia 20192U.S.A.

AbstractThis report presents a review of the U.S. Geolog-

ical Survey (USGS) 2007 assessment of theundiscovered oil and gas resources in Paleogene strataunderlying the U.S. Gulf of Mexico Coastal Plain andstate waters. Geochemical, geologic, geophysical, ther-mal maturation, burial history, and paleontologicstudies have been combined with regional cross sec-tions and data from previous USGS petroleumassessments have helped to define the major petroleumsystems and assessment units. Accumulations of bothconventional oil and gas and continuous coal-bed gaswithin these petroleum systems have been digitallymapped and evaluated, and undiscovered resourceshave been assessed following USGS methodology.

The primary source intervals for oil and gas inPaleogene (and Cenozoic) reservoirs are coal and shalerich in organic matter within the Wilcox Group (Pale-ocene-Eocene) and Sparta Formation of the ClaiborneGroup (Eocene); in addition, Cretaceous and Jurassicsource rocks probably have contributed substantialpetroleum to Paleogene (and Cenozoic) reservoirs.

For the purposes of the assessment, Paleogenestrata have divided into the following four stratigraphicstudy intervals: (1) Wilcox Group (including the Mid-way Group and the basal Carrizo Sand of the ClaiborneGroup; Paleocene-Eocene); (2) Claiborne Group(Eocene); (3) Jackson and Vicksburg Groups (Eocene-Oligocene); and (4) the Frio-Anahuac Formations (Oli-gocene). Recent discoveries of coal-bed gas inPaleocene strata confirm a new petroleum system thatwas not recognized in previous USGS assessments. Intotal, 26 conventional Paleogene assessment units aredefined. In addition, four Cretaceous-Paleogene contin-uous (coal-bed gas) assessment units are included inthis report. Initial results of the assessment will bereleased as USGS Fact Sheets (not available at the timeof this writing).

Comprehensive reports for each assessment unitare planned to be released via the internet and distrib-uted on CD-ROMs within the next year.

2 Program and Abstracts

Deep-Water Depositional Trends of Mesozoic and Paleogene Strata in the Central Northern Gulf of Mexico

Fiduk, Joseph C.CGGVeritas10300 Town Park DriveHouston, Texas [email protected]

Anderson, Lynn E.Genesis Petroleum11120 Lake Forest DriveConroe, Texas, 77384

Schultz, Thomas R.

CGGVeritas

10300 Town Park Drive

Houston, Texas 77072

Pulham, Andrew J.

5312 Gallatin Place

Boulder, Colorado 80303

Abstract

Seismic reflections interpreted to be top Oli-gocene, top Wilcox (approximately base middleEocene), top Cretaceous, top Jurassic, and basementwere mapped across portions of the Green Canyon,Keathley Canyon, Walker Ridge, Lund, SigsbeeEscarpment, Amery Terrace, and Lund South OCSareas of the central northern Gulf of Mexico (Fig. 1).3D Pre-stack depth migrated data were used for map-ping the areas covered by allochthonous salt. 2D Pre-stack time migrated data were used for mapping thearea on the abyssal plain beyond the Sigsbee Escarp-

ment. These data cover approximately 50,000 km2

(19,500 miles2). Well control was obtained from dataavailable through the Minerals Management Service.

Structure maps on the top Oligocene, top Wilcox,top Cretaceous, and basement formed the regional sur-faces between which isopach/isochron maps werecreated to analyze depositional patterns. As might beexpected, basement structure displayed the greatestrelief and complexity. Outboard from the allochtho-nous salt of the Sigsbee Escarpment, half-grabenstructures indicative of rift basin topography wereclearly imaged (Fig. 2). Elsewhere on the abyssal plainisolated, sharp-peaked, elevated basement featureswere observed between more numerous gently slopedhighs. These basement structures typically had reflec-tion terminations against their margins or flanks andcontinuous reflections draping them.

The top Cretaceous and top Wilcox surfacesshow broad regional similarities and show less struc-tural complexity than the basement. Outboard of theSigsbee Escarpment, both surfaces are broadly lobateand have relatively gentle inclinations which rise to theeast. The main observable differences between the two

are: (A) the Cretaceous surface has several isolatedhigh points reflecting underlying basement structuresand (B) the Wilcox surface has a more lobate/interdigi-tate contour character. The top Oligocene surface isless lobate in appearance than either the Cretaceous orWilcox surface and rises to the southeast (Fig. 3).

Isochron maps between the four structural sur-faces reflect the underlying structure and depositionaltrends of the interval. Thus the basement to Cretaceousisochron shows thick Jurassic infill, Cretaceous drapein the grabens (Fig. 2), and thin to no cover over highsin the rifted basement topography. The Cretaceous toWilcox isochron has a broad lobate form that thins gen-tly from west to east. A very subtle down-lappingpattern is visible within the Wilcox interval on Figure2. Deviations from this pattern occur primarily wherebasement structures produce isolated thins. The Wilcoxto Oligocene interval shows a regional gradient ofnorth to south thickening and only a slight influencefrom deeper structure. Down-lapping and thinning tothe north strongly suggest a southerly source for theOligocene interval.

Beneath the allochthonous salt of the SigsbeeEscarpment, all surfaces deepen northward and showmuch greater local variability. Basement is only occa-sionally visible as it generally lies below the fifteenkilometer limit of the available PSDM data. The deep-est area mapped is in Green Canyon where the topOligocene approaches twelve kilometers depth, the topWilcox approaches thirteen kilometers, and the topCretaceous almost fourteen and one half kilometers.These surfaces shallow to less than eight kilometersdeep on the abyssal plain. Three coincident lowsroughly oriented north-south suggest preferred sedi-



ment pathways and possibly areas of thicker originalautothonous salt. A change on the structure and isopachmaps from smooth broadly spaced contours on theabyssal plain to highly variable tightly spaced contourssuggests the location for the original limits of salt dep-osition in this area. This location often lies close to butnot exactly in line with the present day Sigsbee Escarp-ment (Fig. 1).

Of key interest to hydrocarbon explorationistsare any factors that would effect Wilcox deposition. Wehave observed three factors that influence the deposi-tion and thickness of Wilcox age strata in this area:

1. Pre-existing basement highs have caused theWilcox to be thin or absent around those struc-tures. Although basement topography is mostlysmoothed over by the end of the Cretaceous, afew large structures still influenced deposition inthe Wilcox on the abyssal plain beyond the Sigs-bee Escarpment.

2. Salt nappes and salt pillows have caused thinningof Wilcox strata over those structures. Our inter-pretation indicates multiple kilometer thick saltnappes extruded beyond the limits of the originalsalt basin during the Cretaceous (Figs. 4 and 5).Inflated salt pillows associated with the nappeslay along the boundary of the salt basin. Thoughnow deflated, the presence of these salt pillowsand other salt pillows updip are recorded by thedepositional thinning of Wilcox strata abovethem. These allochthonous bodies provided thecore structure over which Wilcox and Miocenereservoirs are folded or draped at Chinook,Atlantis, Das Bump, and other important deep-water discoveries. The location of allochthonoussalt at the onset of Wilcox deposition is appar-ently coincident with the pronounced increase innortherly dips of the Mesozoic and Paleogenestrata. This relationship is consistent with origi-nally thick autochthonous salt above the deepestmapped basement.

3. Sites of continued salt withdrawal from theautochthonous level into growing salt structuresdirectly affected Wilcox sediment thickness.Such sites would have been primary candidatesfor the location of Wilcox sediment fairways.Identification and elimination of salt feederswould help in refining/defining these pathways.

Deposition of the Wilcox strata can be broadlydivided into two paleogeographic domains: (A) a rela-

tively complex north-westerly region characterized bypre-existing, elevated sea-floor, salt-cored structuresand sites of contemporaneous salt evacuation, and (B) arelatively simple south-easterly region characterized bya near flat and smooth sea-floor rarely punctuated byunburied basement structures. The transition betweenthese two regions should mark changes in Wilcox dep-ositional styles.

In the more complex topographic region, Wilcoxdepositional events were forced to interact with rela-tively rapid changing sea-floor dips. Whereas in themore simple region to the southeast, a much moreunconfined sea-floor presented limited impediment towidespread expansion of depositional events exitingthe more complex region to the north-west.

Drilling of Wilcox strata to-date has been mainlyin the simpler south-easterly region and in the transi-tion zone to the more complex Wilcox geometriestowards the north-west.

Figure 4 shows an example of one salt nappe andits contractional deformation front that lies in closeproximity but basinward of the Sigsbee Escarpment.Thrust relationships suggest that the nappe continuedto move/inflate until the end of the Cretaceous. Aninflated salt pillow associated with the nappe is presentthrough the Oligocene but then deflates during theMiocene. This interpretation is supported by the thinbut depressed Wilcox and Oligocene section behind thenappe today. We predict that the edge of the salt basinlies behind the nappe, below where the Wilcox and Oli-gocene intervals begin dipping to the north.

Figure 5 shows another example of a salt nappethat lies in about thirty kilometers inside of the SigsbeeEscarpment. This nappe does not have a deformationalfront associated with it. But an inflated salt pillow isassociated with this nappe as in Figure 4. Similar toFigure 4, the interpretation is supported by a thin butdepressed Wilcox section behind the nappe. In contrast,evacuation of the pillow begins in the Oligocene, asevidenced by the Oligocene age turtle structure. Evacu-ation continues into the Miocene until the pillow iscompletely deflated. The nappe remnant is all thatremains of this salt body. Unique to these two exam-ples, but possibly typical of most salt pillows aroundthe edge of the salt basin, loading has forced salt back-wards (updip) into the salt basin. In Figure 4, thereversal of salt movement is about ten kilometers. InFigure 5, the reversal of salt movement may be twentyto twenty-five kilometers.


Structural Style and Evolution of Traps in the Paleogene Play, Deepwater Gulf of Mexico

Mount, VanDull, KathyMentemeier, SamAnadarko Petroleum CorporationP. O. Box 1330Houston, Texas [email protected]

AbstractA basic understanding of the structural evolution

and timing of trap development in the deep waterPaleogene play is critical in prospect risk assessment.In this paper, regional and prospect scale interpreta-tions and restorations are used to illustrate structuralstyles and evolution of common traps associated withthe Paleogene play in the north-central and northwestdeep water Gulf of Mexico. In this area, the interplaybetween salt tectonics and depositional systemsthroughout Late Mesozoic and Tertiary time hasresulted in complex scenarios of structural trap devel-opment—which can be quite variable in style andtiming. Processes typically involved in the formation ofthese traps are discussed, including: (A) subsidence ofsedimentary depocenters into an autochthonous saltlayer and synchronous salt canopy emplacement via asalt stock feeder network that borders the depocenters;(B) a component of regional, downdip contraction

above the autochthonous salt layer (the magnitude ofwhich is variable, often relatively small—but largeenough to squeeze the salt stock feeder system, andgenerate frontal fold structures at the downdip limit ofthe salt basin), and (C) weld development through dis-placement of salt within large salt features (salt featuresthat are part of the canopy system, or large salt featuresthat are rooted to the autochthonous salt layer) by rela-tively late deposition. Several structural case studies ofcommon trap styles (generated by the processes listedabove) are used to illustrate the complexity anddynamic history of trap formation. Examples of Paleo-gene play trap types discussed include: (1) three-waydip closed structures bounded by salt stocks, squeezedsalt stocks, or salt welds, and (2) four-way dip closedanticlinal structures, which are formed either inresponse to contraction or subsidence of a sedimentarydepocenter onto a base of autochthonous salt surface.



Chronostratigraphic Framework for the Wilcox Formation (Upper Paleocene–Lower Eocene) in the Deep-Water Gulf of Mexico: Biostratigraphy, Sequences, and Depositional Systems

Zarra, LarryChevron North America Exploration and Production Company1500 Louisiana StreetHouston, Texas [email protected]

Abstract The Wilcox Formation (upper Paleocene–lower

Eocene) is a world-class hydrocarbon resource in theGulf of Mexico. Since the late 1920’s, the onshore Wil-cox trend has produced primarily gas from fluvial,deltaic, and shallow marine sandstone reservoirs fromsouthwest Louisiana to south Texas and northeast Mex-ico. Total estimated ultimate recoverable reserves(EUR) from the onshore trend exceed 30 trillion cubicfeet (TCF) of natural gas, or 5 billion barrels of oilequivalent (BBOE), most of which has already beenproduced. Recent exploration in the offshore Gulf ofMexico has documented a deep-water Wilcox turbiditetrend containing significant hydrocarbon resources.Since 2001, exploration and appraisal drilling has dis-covered nearly 2.5 billion barrels of potentiallyproducible oil reserves in the deep-water Wilcox trend.

Chronostratigraphic analysis is the key to corre-lating accurately the established onshore Wilcox trendto the new deep-water Wilcox trend. Stratigraphy forthe onshore Wilcox is documented in numerous publi-cations, but there are differences in ages assigned tovarious lithostratigraphic components of the section. Anew onshore chronostratigraphic model based on inte-grated paleontologic data from downdip wells ispresented to clarify the ages of Wilcox sequences in theTexas subsurface. This onshore model is consistentwith the new chronostratigraphic framework developedfor the deep-water Wilcox.

The primary focus of this paper is a detaileddescription of a new deep-water Wilcox chronostrati-graphic framework. Five chronostratigraphic units arerecognized. In ascending order, they are; Wilcox 4,Wilcox 3, Wilcox 2, Wilcox 1B, and Wilcox 1A. Theseunits represent early lowstand turbidite deposits of sin-gle third-order sequences or groups of third-ordersequences. Each unit is defined by relevant biostrati-graphic control, sequences and systems tracts,depositional systems, and sedimentary processes.

On the basin floor, early lowstand sandy turbiditesequences are characterized as channelized fan systemsor distributary fan systems. Sand-poor intervals on thebasin floor are in bypass zones or are condensed. Thelower slope is mudstone dominated by turbidite chan-nels and discrete ponded fans. Sedimentary processesare interpreted from approximately 3,000 feet of con-ventional core, which is used to calibrate interpretationof depositional systems.

Since the initial deep-water Wilcox well at Bahaprospect in 2001, more than 20 wildcat wells have pen-etrated Wilcox turbidites, resulting in a 65 to70 percentdiscovery rate. With continued exploration andappraisal success in the last six years, the Wilcox hasbecome an increasingly important trend in the deep-water Gulf of Mexico.



Rift Models and the Salt-Cored Marginal Wedge in the Northern Gulf of Mexico: Implications for Deep-Water Paleogene Wilcox Deposition and Basinwide Maturation

Pindell, JamesKennan, LorcanTectonic Analysis, Ltd.Chestnut House, DunctonWest SussexGU28 [email protected]

AbstractTwo primary issues continue to plague geologi-

cal assessments of the Gulf of Mexico. The first is thecommon view of “mother salt,” with terms such as“basinward depositional limit” or “onlap limit” of saltbeing used in reference to the deep Gulf basin withoutapparent concern for whether or not this limit is deposi-tional. Backstripping techniques clearly show that thecrust in the deep Gulf is typical oceanic crust, accreted(crystallized) at about 2.7 km paleo-water-depth, suchthat this contact cannot be a depositional one if the saltwas deposited in shallow water in a basin more or lessfull to sea level. We argue that the seaward salt limit,even where not reactivated in the Tertiary, is a struc-tural contact formed by salt flow onto oceanic crust.The second is the portrayal of the abyssal plain con-tinuing well north of today’s continental slope prior tothe Miocene, and approaching the Sligo-Stuart Citycarbonate shelf edge (to beneath present-day onshoreareas) in the Late Cretaceous. These portrayals appearto presume that the Louann Salt was conveniently

“stored” beneath the northernmost abyssal plain (i.e.,without bathymetric expression) until the Cenozoic.This paper sets out to revise these long-held concepts,and to replace them with alternatives that explain pri-mary observations in the Gulf much better. We start byassessing the Jurassic rift configuration and its impacton subsequent basin development, which in our viewwas very different to traditional models. We proposethat a “salt-cored marginal sediment wedge” existedbetween the Sligo-Stuart City carbonate shelf edge andthe deep water Wilcox trend which provided a continu-ous (but perhaps stepped) continental slope, downwhich Wilcox clastic sediments were free to flow fromsource to sink without first having to cross hundreds ofkilometers of flat abyssal plain to reach their final posi-tion. In addition, the analysis hints at a mechanism forthe incision of deep canyons (e.g., Yoakum) along thenorthern and western Gulf shelf margins and leads us topropose a new maturation mechanism in the northernGulf margin.



Lower Paleogene Chronostratigraphy: A Review

Rosen, Rashel N.NCR & AssociatesHouston, [email protected]

Abstract Although some unpublished planktonic foramin-

iferal zonations were being used for onshore subsurfaceWilcox correlation prior to 1994, Rosen et al. (1994)was one of the first publications suggesting a testedzonation and relating it to relative changes of coastalonlap. Since 1994, hundreds of additional wells havebeen analyzed, resulting in the refinement of the zona-tion and a better understanding of the depositionalenvironment.

A refined early Eocene to basal Paleocene zona-tion for subsurface Reklaw–Wilcox–Midwayformations, based on 21 planktonic and 24 benthonicforaminiferal datum markers, has been established.

Their correlation to global planktonic P-Zones as wellas the local benthonic foraminiferal zones is given. Theenvironment in which they were deposited and theirrelation to 13 condensed sections, as related to maxi-mum flooding surfaces and system tract boundaries insubsurface Texas and Louisiana, are discussed. Theirsimilarities and differences with the recent ultra-deepwater Wilcox discoveries are compared.

This zonation is based on analysis of more than600 wells, construction of several regional environmen-tal maps, and integration with electric logs and 2,500miles of high-resolution seismic data, in the Wilcoxtrend, south Texas to central Louisiana.



Paleogene Calcareous Nannofossil Bioevents from the Fold Belts of the Deep-Water Central Gulf of Mexico

Denne, Richard A.Applied Biostratigraphix51 Midday Sun Pl.The Woodlands, Texas [email protected]

Abstract Although the Oligocene to middle Eocene sedi-

ments of the fold belts of the deep-water central Gulf ofMexico are generally condensed and fossiliferous,many open-ocean and nearshore calcareous nannofossilmarkers are very rare or non-existent, necessitating theuse of non-standard markers and assemblage changes(bioevents). These bioevents are based on species’highest occurrences, consistent last occurrences, down-hole abundance increases, morphometric changes, andacmes. Forty-five bioevents have been identified in theOligocene to Middle Eocene of the northern Gulf Basin(onshore and offshore) utilizing 52 calcareous nanno-fossil species. As 10 of these horizons are based onnearshore forms and not recognized in the deep-water,35 bioevents have been found in the deep-water Gulf ofMexico. This compares to the 14 zones and subzonesof the standard nannofossil zonation schemes. Twenty-

six additional species have been determined to be use-ful as zonal “flags.”

The lower Eocene and upper Paleocene sedi-ments are expanded and contain few nannofossils.Seventeen bioevents have been identified in the north-ern Gulf Basin utilizing 25 calcareous nannofossilspecies. Due to the low fossil abundances and possibleunconformities, only 10 of these bioevents have beenfound in the deep-water Gulf of Mexico. There are 12standard zones and subzones within this interval, but 10of the zonal boundaries are defined by species’ bases,and therefore not reliable in a petroleum industry con-text. Thirty-three additional species are useful as zonal“flags”. The lower Paleocene section is generally eithervery condensed or missing, with the exception of theK/T boundary debrite.



High Resolution Correlations: Projecting Global Data Sets into Gulf Coast Sedimentary Sequences Using Biostratigraphy and Magnetic Susceptibility

Ellwood, Brooks B.Department of Geology and GeophysicsLouisiana State UniversityE235 Howe-Russell Geoscience ComplexBaton Rouge, Louisiana [email protected]

Fillon, Richard H.Earth Studies Group3730 Rue NicholeNew Orleans, Louisiana 70131

Waterman, Arthur S.Paleo-Data, Inc.6619 Fleur de Lis DriveNew Orleans, Louisiana 70124

Kassab, AhmedGeology DepartmentFaculty of ScienceAssiut UniversityAssiut 71516, Egypt

AbstractHigh resolution stratigraphy is important in under-

standing sedimentary systems in the Gulf of Mexicobasin. We have been using magnetic susceptibility mea-surements, a relatively new, abiotic method, tocharacterize global stratotype sections defined for thePaleogene and projecting that work into the Gulf Coast.When magnetic susceptibility is combined with chro-nostratigraphically calibrated biostratigraphic data, suchas that provided by our ongoing multi-well Gulf of Mex-ico basin-wide graphic correlation project, very highresolution is possible. Here we show preliminary datafor the Paleocene, including the Paleocene-Eoceneboundary stratotype in Egypt, and use characteristic inthat data to identify the boundary location in the GulfCoast. The MGS-1 Harrell core (southeastern Missis-

sippi) and the OSM-2 Wahalak core (southwesternAlabama) penetrate Wilcox “type” section, samplingmember beds of the Clayton, Porters Creek, Naheola,Nanafalaya, Tuscahoma, and Hatchetigbee formations.Results of this investigation illustrate the potential utilityof the methods for detailed stratigraphic studies in theGulf Basin. We plan to extend our Gulf Basin magneticsusceptibility chronology through the Eocene in aneffort to clarify unresolved stratigraphic problems inultra deep-water Gulf of Mexico sediments of Paleoceneand Eocene age that are important targets of the petro-leum exploration industry. Of particular interest will beexamination of the age and duration of the Eocene fora-miniferal and calcareous nannofossil “barren interval”and the radiolarian zones identified within it.



Wilcox Submarine Canyons: Distribution, Attributes, Origins, and Relationship to Basinal Sands

Galloway, William E.Institute for GeophysicsJohn A. and Katherine G. Jackson School of GeosciencesThe University of Texas at Austin10100 Burnet Rd. (R2200)Austin, Texas 78758-4445

Abstract

The Wilcox Group contains most of the docu-mented large submarine canyons and slump scarswithin the northern Gulf of Mexico Paleogene section.Indeed, comparable abundance and scale of canyons isnot seen again in the Gulf until the late Neogene. Fourstyles of shelf margin excavation morphologies can bedifferentiated based on published examples:

1. Simple slump scars.2. Submarine canyons created by retrogradational

slumping.3. Graded, mature submarine canyons.4. Valley-form cross-shelf gorges.

These styles appear to be part of a continuum;many examples share elements of two or more types.However, most canyons have been mapped using lim-ited well control, and their illustrated morphology maylargely reflect the interpreter’s use of fluvial morpho-logic analogues as much as data constraints.

Wilcox canyons typically occur in geographi-cally localized clusters, which are centered beneath thecentral and upper Texas coastal plain and the centralLouisiana coastal plain. Two of the clusters occur onthe flanks of the lower–middle Wilcox Houston deltasystem; the third lies on the progradational front of thelower Wilcox Holly Springs delta system. Canyon clus-ters appear to occur at or near major tectonic-stratigraphic domain boundaries of one or more Wilcoxdeposodes. Several of the largest canyons, includingthe Yoakum canyon, correlate with two thin, regionalmarine flooding units, the Yoakum and Big shales.However, known canyons also occur at several addi-tional stratigraphic positions at the base of and withinthe Paleocene lower Wilcox genetic sequence. Recur-rent shelf margin mass wasting events could have beentriggered by seismic shocks initiated along the Lara-mide tectonic front, which lay along the west andnorthwest margin of the Gulf basin.

Detailed analyses of the Yoakum and Lavacacanyons showed that they were excavated (at least intheir late stage of development) across the Wilcox shelfand deltaic platform during times of local to regionaltransgression by processes of headward slumping anderosion by submarine currents. Canyon cutting and fill-ing occurred sufficiently rapidly that steep (up to thirtydegree) unstable canyon walls consisting of unconsoli-dated slope and prodelta muds were buried andpreserved. Infilling occurred during subsequent progra-dational advance of the shore line. The obviouscanyons were largely mud filled. However, sand bodieswere present within the fill of both the Yoakum andLavaca canyons. Fill of the Lavaca canyon was exten-sively cored and consists of turbidite channel and leveefacies suspended within volumetrically dominant,muddy debris flow deposits. Intact slump blocks ofcanyon-bounding delta front successions were alsofound. Updip reaches of canyons typically included alower onlap fill and a superimposed, mud-dominatedprogradational fill.

The presence of clusters of canyons along theupdip Paleocene continental margin suggests a geneticrelationship to turbidite channel and lobe sand bodiesthat constitute the reservoirs for the recent deep-waterPaleogene discoveries. Successive canyons would haveserved to collect and focus sediment transport acrossthe shelf and down the nascent Cenozoic continentalslope, creating a submarine canyon—fan couple. Suchhighly evolved sediment transport systems would allowefficient separation of bed load (sand) from suspendedload (silt/clay) as sediment gravity flows traveled fromthe shelf margin and upper slope, through mature can-yons, and onto large, abyssal plain fan systems withwell segregated upper, middle, and lower fan prov-inces. The high net/gross sections of channeledturbidite lobe sand bodies penetrated in the Mississippi


Fan and Perdido fold-belt fairways likely have accumu-lated in the sand-rich middle fan. Paleogeographicreconstruction places the sand-rich middle fans more

than 200 km basinward from the slope toe. Althoughimpressive, such dimensions are typical of many sandyQuaternary abyssal fan systems.


Recent Geological Understanding of the Chicontepec Erosional “Paleocanyon,” Tampico-Misantla Basin, Mexico

Cossey, Stephen P.J.Cossey and Associates Inc.P.O. Box 1510Durango, Colorado 81302 [email protected]

AbstractThe Chicontepec Formation in eastern central

Mexico has long been explored for its oilaccumulations and contains several largeunconformities, which in the past seem to have beenmiscorrelated across the Tampico-Misantla Basin. Theformation is of current interest because it may help usto understand the mechanisms of delivery of theWilcox sands in the deep Gulf of Mexico. In thenorthern part of the Chicontepec play, outcrop dataindicate that a major unconformity occurs at about 55Ma (i.e., the Paleocene/Eocene boundary). Outcropsoverlying this unconformity show a “classic” sectionabout 150 meters thick; mass transport complexes ontop of the unconformity are in turn overlain by sheetsandstones, channels, and channel levee complexes.

In the central part of the play, there is a majorunconformity in the Eocene, between 47 and 53 Ma(probably late early Eocene). In the southern part of theplay (in the Agua Fria Field area) the first major ero-sional unconformity is between 43.6 and 50.4 Ma. Inthe extreme southern part of the play, in the PresidenteAlemán area, the oldest unconformity is at approxi-mately 40 Ma. The unconformities all have beengenerated in submarine environments. Without the ben-efit of seismic and high-resolution biostratigraphic

data, earlier workers miscorrelated these unconformi-ties and assumed that they were one largeunconformity, forming the Chicontepec “paleocanyon.”All the unconformities are regional events and occurthroughout the basin.

The 43.6 to 50.4 Ma erosional event (unconfor-mity A) is a correlatable seismic event across a largeproportion of the Tampico-Misantla Basin. This eventhas been cored in at least two wells. In the closest wellto the canyon, a 110 meter thick mass transport depositimmediately overlies the unconformity. The masstransport deposit consists of a basal 30-meter pebblymudstone debrite, overlain by an 80 meter thick slump.Recent interpretation in the Agua Fria, Tajin andCoapechaca (ATC) fields, west of Poza Rica, Veracruz,has allowed more detailed mapping of the erosionalunconformities and a better estimate of the volume ofmaterial removed at unconformity A. In this area, thefeature is up to 6 km wide and, in some places morethan 600 meters of consolidated Paleocene and Creta-ceous strata have been removed. Production from theATC fields west of Poza Rica, is from the infill of the“paleocanyon” (canyon-fill trap) and the pre-erosionstrata (canyon truncation trap), and the trapping mecha-nism is both stratigraphic and diagenetic in nature.



A New Depositional Model for the Deep-Water Gulf of Mexico Wilcox Equivalent Whopper Sand—Changing the Paradigm

Berman, Arthur E.Labyrinth Consulting Services, Inc.Houston, [email protected]

Rosenfeld, Joshua H.Yax Balam, Inc.Granbury, Texas

Introduction

The lower Tertiary (Paleogene) of the offshoreGulf of Mexico has emerged as an important frontieroil and gas play as there are a series of major discover-ies in the deepest parts of the Alaminos Canyon,Keathley Canyon and Walker Ridge OCS protractionareas. Reservoirs consist of thin, channelized Eocene toOligocene distal turbidite sands and thick Paleocene-Eocene amalgamated sheet sands. The latter are collec-tively named the “Whopper sand.” The pre-Oligoceneportion of this sequence correlates with the onshoreWilcox Group. The unique character of the Whopper isits generally high sand content (~70%) and great thick-ness (>1,000 feet), although deposited hundreds ofmiles seaward of the Wilcox shelf margin and slope.The presence of this voluminous sand, reported to con-tain substantial amounts of coarse-grained sand, so farbeyond the contemporaneous shallow marine depo-centers, challenges explorers to consider alternatescenarios to earlier Wilcox depositional models.

A Paleocene sea-level drop in the Gulf of Mexicoby as much as several thousand feet was discussed byRosenfeld and Pindell (2002, 2003) who proposed thattectonic closure of the Florida-Yucatan Straits isolatedthe Gulf of Mexico from the world ocean, causingrapid evaporative drawdown. This hypothesis was pro-posed to explain massive sandstone reservoirs that hadjust been discovered in the deep-water Perdido FoldBelt (Alaminos Canyon) of the western Gulf of Mex-ico. By 2007, at least 19 exploratory wells penetratedthe Whopper sand across a 300 mile-wide swath of thedeep Gulf of Mexico. Twelve of these wells have foundoil and gas (Fig. 1 and Table 1). Reserve estimates forthe deep-water lower Tertiary reservoirs currentlyrange from 3 to 15 billion barrels of oil equivalent, andfirst production is scheduled for 2009-2010.

Published interpretations (e.g., Meyer et al.,2005; Seitchik and Powell, 2006) interpret the Whop-per sand to be a distal submarine basin floor fan depositwithin an uninterrupted shallow to deep-water facies

succession from the Wilcox shelf margin to the WalkerRidge OCS protraction area. This creates serious prob-lems of scale as no other Cenozoic depositional systemhas delivered sand so far from the shelf margin, muchless a high net-to-gross sand sequence over 1000 feetthick more than 225 miles from the base of the coevalcontinental slope that would have required sand-domi-nated, gravity-driven density flows to travel hundredsof miles across a virtually flat basin floor.

Defenders of the distal submarine paradigmmight claim that modern deep-water systems are capa-ble of transporting sand onto the basin floor hundredsof miles from the base of the slope as, for example, inthe Pleistocene Gulf of Mexico. Pleistocene basinalsand bodies, however, are confined to the main chan-nels in shale and silt dominated fans. In fact, turbiditedepositional currents require high clay content in orderto prevent drop-out of suspended sand near the base ofthe continental slope. Corresponding shale volumeshave not been found in association with the Whopper.

Rosenfeld and Pindell (op. cit.) proposed that themost reasonable explanation for the observed faciesand thickness of the Whopper sand was a brief, thoughextreme, intra-Wilcox Gulf of Mexico sea-level dropapproximately 55 million years ago (Ma) around thePaleocene-Eocene boundary. This sea-level fall canonly be explained by evaporation following the tectonicisolation of the Gulf of Mexico due to the collision ofthe Cuban Arc with the Florida-Bahamas and Yucatanplatforms. The Gulf dropped about 6000 feet belowworld sea level (Fig. 2) leading to the rapid prograda-tion of sand-rich fan deltas, and slope and basin floorfans. Sand reached the deep basin during this forcedregression by continual recycling ("cannibalization") ofpreviously deposited material.

The presence of thick, widely distributed Wilcoxsandstones in the deep-water Gulf of Mexico is anunprecedented anomaly in the Gulf Basin that cannotbe adequately explained by existing deep-water models



from either the modern or the ancient. Although diffi-cult to visualize, there are several additional lines ofevidence that support the drawdown hypothesis. Quot-

ing Conan Doyle’s Sherlock Holmes, "When you haveeliminated all which is impossible, then whateverremains, however improbable, must be the truth.”


Wilcox Structural Variations in Walker Ridge and Central Keathley Canyon

Seitchik, Adam M.Powell, TimothySullivan, RobertDevon Energy Corp1200 Smith St.Houston, Texas [email protected]

Adams, Stephen D.Newfield Exploration Co.

1401 17th Street, Suite 1000Denver, Colorado 80202

AbstractDetailed study of exploration wells penetrating

the Wilcox interval in the Walker Ridge and KeathleyCanyon protraction areas, Gulf of Mexico, support thepresence of an extensive, correlative, Wilcox deposi-tional system. They also reveal differences in structuralstyles and timing of formation. While mobilization ofthe Jurassic autochthonous salt layer results in manydeep structures, their evolution and style varies acrossthe region. South of Green Knoll in Walker Ridge, thestructural style exhibits characteristics of compression

and inflation, and greatest growth is in the middle tolate Miocene. This style transitions into structuresalong remnant polygonal salt ridges resulting fromevacuation of the autochthonous salt layer into theallochthonous salt canopy during the middle to lateMiocene. Farther west into Keathley Canyon, earliersalt movement, possibly generated by up-dip Oli-gocene extension, creates structures along remnant saltridges associated with salt evacuation and inflation.



Deep Imaging of the Paleogene, Miocene Structure and Stratigraphy of the Western Gulf of Mexico using 2D Pre-Stack Depth Migration of Mega- Regional Onshore to Deep Water, Long-Offset Seismic Data

Radovich, Barbara J.Silver Grass Enterprises 101 North Hall DriveSugar Land, Texas [email protected]

Connors, Christopher D.Department of GeologyWashington and Lee UniversityLexington, Virginia 24450

Moon, Jerry

Global Energy Strategies, LLC.

205 Millbrook


Abstract The northwestern Gulf of Mexico basin has

emerged as an archetype example of a robust, progra-dational passive margin system that induces substantialtranslation over underlying detachments due to gravita-tional loading. Despite this recognition, the difficultiesin deep imaging of seismic data have continued toobscure key features of this deformation. Mega-regional, 2D, long-offset PSDM data help advance theinterpretation of the Paleogene and Miocene of theGulf of Mexico. We present results from new seismicline composites made up of reprocessed PSDM legacyonshore data (sourced from SEI and GPI), and newlyacquired ocean bottom cable data and marine streamerdata acquired and processed by GX Technology. Keylines from this dataset link robust, onshore shelf low-stand wedges to deep-water sediments and more clearlyimage deep structural styles and salt remobilizationevents. The lines span approximately 300 miles (500

km) from onshore Texas to the ultra-deep water andfinally show the full size of geologic features, includinga regional salt weld that starts onshore at the topEocene and extends for over 100 km, ramping up toOligocene. The interpretation highlights the effects ofgravitational forces on the stratigraphic section anddelineates prominent extensional faults that sole-out atmajor detachment levels and are linked to a newly rec-ognized Paleogene thrust belt, as well as to previouslydocumented Oligo-Miocene contractional belts. Signif-icant lateral translation occurs along thesedetachments. The data image a key fault connectionfrom Oligo-Miocene extensional faults down to theLouann detachment surface, and the interpretationsprovide viable scenarios for Oligo-Miocene expansionto drive the Perdido fold belt along the Louanndetachment.



Source Rock and Reservoir Controls on Deepwater Prospectivity in the Gulf of Mexico Paleogene Play

Matava, Tim

GX Technology Corporation and L & W Geosciences, Inc.

19707 Ivory Brook Drive


[email protected]

Radovich, BarbaraMoon, JerryGX Technology Corporation and Silver Grass

Enterprises, Inc.2101 Citywest BlvdBuilding 3Houston, Texas 77042

AbstractOnshore at the rim of the Gulf of Mexico basin

near Dallas, Texas, deposition in the Fort Worth basinduring the Cretaceous and early Tertiary is the primaryfactor controlling maturation of the Mississippian ageBarnett Shale source rock. During Laramide time,uplift of up to 2 km in the Fort Worth basin ends thegeneration of hydrocarbons from the Barnett Shale andthe eroded sediments constitute a significant source ofsediment for the Gulf of Mexico Basin. Although theFort Worth basin is only one of many sources of sedi-ment to the Gulf of Mexico, it is the accumulation ofmaterial from these ages that affects reservoir proper-ties of the Paleogene age sediments in the deep waterGulf of Mexico. The emerging deep water Paleogeneplay in the Gulf of Mexico has seen several large dis-coveries in recent years in water depths greater than 2km. Discovered hydrocarbons have gas-oil-ratios(GOR) significantly less than bubble point pressuressuggesting early source rock maturity and late migra-

tion of hydrocarbons into traps. Paleogene reservoirsare typically encountered at depths greater than 5 kmbelow mud line, and reservoir temperatures are greaterthan those encountered in lower Miocene reservoirs inthe Green Canyon and Mississippi Canyon areas.These reservoir temperatures suggest quartz diagenesismay be a significant factor affecting the flow rates inindividual wells in the play. This paper links togetherthe history of Paleozoic onshore Fort Worth basin inthe upper Gulf Coast and the Paleogene section in thedeep water Gulf of Mexico utilizing long, regional 2Dseismic lines extending from the rim of the Gulf ofMexico Basin to the current abyssal plain. Results fromthe two dimensional, integrated basin model developedfrom this present day section allow pressure, tempera-ture, and effective stress histories to be developed overthe Gulf of Mexico Basin. This study is the beginningof a more integrated physical understanding of thesetwo diverse but related plays.



USGS Assessment of Undiscovered Oil and Gas Resources for the Oligocene Frio and Anahuac Formations, U. S. Gulf of Mexico Coastal Plain and State Waters: Review of Assessment Units

Swanson, Sharon [email protected], Alexander [email protected], Peter [email protected]. Geological SurveyNational Center, MS 956Reston, Virginia 20192

AbstractThe Oligocene Frio and Anahuac formations

were examined by the U.S. Geological Survey (USGS)as part of an assessment of technically recoverableundiscovered conventional and unconventional hydro-carbon resources in Paleogene and Neogene strataunderlying the U.S. Gulf of Mexico Coastal Plain andstate waters. Work included the identification of struc-tural, stratigraphic, and tectonic relations betweenpetroleum source rocks and migration pathways to Frioand Anahuac reservoirs; preliminary evaluation of thepotential for shallow (less than 3,000 ft) biogenic gasaccumulations; and evaluation of the potential for deep,undiscovered gas and oil accumulations in slope andbasin floor areas. All assessments were conductedusing USGS methodology (http://energy.cr.usgs.gov/oilgas/noga/methodology.html). Final products fromthe USGS assessment of the Paleogene and Neogenewere reported in USGS fact sheets (Dubiel et al., 2007;Warwick et al., 2007).

Five assessment units for the Frio Formationwere defined, and three of these were based on thecharacter of the reservoirs in relation to growth faultsand other related factors: (1) the Frio stable shelf oil

and gas assessment unit, which contains thin (averagethickness of 34 ft) and shallow reservoirs (averagedepth of 4,834 ft); (2) the Frio expanded fault zone oiland gas assessment unit, which contains thick (averagethickness of 56 ft) and deep reservoirs (average depthof 9,050 ft) in over-pressured intervals; and (3) the Frioslope and basin floor gas assessment unit, which haspotential for deep gas (greater than 15,000 ft) andextends from the downdip boundary of the expandedfault zone to the offshore State/Federal water boundary.The fourth Frio assessment unit is the Hackberry oiland gas assessment unit. The Hackberry embayment ofsoutheast Texas and southwest Louisiana consists of aslope facies in the middle part of the Frio Formation.The fifth unit, the Frio basin margin assessment unit,extends from the updip boundary of the Frio stableshelf oil and gas assessment unit to the outcrop of theFrio. Because the basin margin unit has no productiondata and little potential for biogenic gas, it was notassessed; however, a description of this unit will beincluded in the final assessment report. An assessmentunit also was defined for the Anahuac Formation, amajor transgressive unit overlying the Frio.




http://energy.cr.usgs.gov/oilgas/noga/methodology.html

http://energy.cr.usgs.gov/oilgas/noga/methodology.html

http://certmapper.cr.usgs.gov/data/noga00/natl/text/CH_21.pdf





Paleogene Stratigraphic Revision and Tectonic Implications, Gulf of Mexico Abyssal Plain

Winker, Charles D.Shell International E&PP.O. Box 281Houston, Texas [email protected]

AbstractPaleogene stratigraphy of the northern Gulf of

Mexico abyssal plain was revised using baselap sur-faces that define major depocenter shifts. Age andlithologic control was provided by ties to wells in thePerdido fold belt. The three major Paleogene units,named for coeval units in Texas and Louisiana, are Wil-cox-Midway (WM), Vicksburg-Jackson-Claiborne(VJC), and basal Miocene-Anahuac-Frio (BMAF).Late Laramide (Paleogene-lower Eocene) Wilcox sub-marine fans were sourced from the north, west, and

northwest; each of three subunits has a different depo-center. The VJC submarine fan depocenter (middleEocene to lower Oligocene) reflected sediment influxfrom post-Laramide uplift in Mexico and simultaneoussediment starvation from Texas and Louisiana. BMAFdepocenters (middle Oligocene to lowermost Miocene)indicated a return to sediment input from the north andnorthwest. Deformation of the Perdido foldbelt beganduring BMAF time, following deposition of the Friofan.



Exploration and Appraisal Challenges in the Gulf of Mexico Deep-Water Wilcox: Part 1—Exploration Overview, Reservoir Quality, and Seismic Imaging

Lewis, JenniferClinch, SimonMeyer, DaveRichards, MattSkirius, ChristineStokes, RonZarra, LarryChevron North America Exploration and Production Company1500 Louisiana Street


[email protected]

AbstractThe deep-water Wilcox trend covers more than

34,000 mi2, extending across the Alaminos Canyon,Keathley Canyon, and Walker Ridge protraction areas,plus parts of adjacent protraction areas and Mexicanterritorial waters. Discoveries are in turbidite sands thathave been deposited in lower slope channels and pon-ded fans to regionally extensive basin floor fansystems. Primary trap styles are compressional Louannsalt-cored symmetrical box folds, symmetrical salt pil-lows, and asymmetrical salt cored thrust anticlines.More than 20 wildcat wells have been drilled in theWilcox Trend. Recoverable reserves for each of the 12announced discoveries range from 40 to 500 millionbarrels of oil (MMBO). Ultimately, the Wilcox trendhas the potential for recovering 3 to 15 billion barrels

of oil reserves (BBO) from these discoveries and addi-tional untested structures. Many technical issues needto be resolved to move the billions of barrels ofresources trapped in deep-water Wilcox structures torecoverable economic reserves. Exploration challengesinclude well depths up to 35,000 feet subsea, waterdepths ranging from 4,000 to 10,000 feet, and salt can-opies from 7,000 to more than 20,000 feet thick.Allochthonous salt covers 90% of the trend, complicat-ing regional reconstructions and resolution ofindividual structures. Appraisal challenges include:delineating and modeling reservoir quality, sand distri-bution, and flow capability; improving complex sub-salt images; and developing cost effective drilling,completion, facility, and infrastructure designs.


http://www.conferencearchives.com/aapg2007/sessions/player.html?sid=07041202




Exploration and Appraisal Challenges in the Gulf of Mexico Deep-Water Wilcox: Part 2—Porosity, Permeability, and Producibility

Stokes, Ron

Clinch, Simon

Meyer, Dave

Lewis, Jennifer

Richards, Matt

Skirius, Christine

Zarra, Larry

Chevron North America Exploration and Production Company

1500 Louisiana Street


[email protected]

Introduction

Conventional deep-water Gulf of Mexicoappraisal projects have typically focused on character-izing original oil in place (OOIP) by gathering data onreservoir distribution and defining an oil/water contact.Earlier deep-water Gulf of Mexico appraisal projectsinvolved drilling numerous wells to determine reservoirdistribution in complex depositional settings. Industryis currently experiencing a drive to accelerate deep-water appraisal projects, largely due to rig shortages,increasing well costs, and a significant turnover indeep-water leases. Appraisal projects need to under-stand and reduce subsurface uncertainty, despitelimited well control. The challenge to accelerateappraisal and determine economic viability is particu-larly difficult in the deep-water Wilcox trend, wherethere are significant uncertainties concerning perme-ability distribution.

A key issue in appraising deep-water lower Ter-tiary Wilcox discoveries is the prediction ofpermeability. Wilcox permeability values are more thanan order of magnitude lower than values typical of con-ventional upper Tertiary deep-water plays in the Gulfof Mexico. In typical upper Tertiary plays, reservoirquality is easily evaluated with conventional wireline

log suites, but in much of the deep-water Wilcox trend,permeability and producibility are more difficult toestimate using wireline logs alone. Calibration of logdata to whole core, supplemented with rotary side wallcores, has improved the estimation of permeability, andhas also confirmed a long hydrocarbon column. Addi-tionally, extended production tests of Wilcox reservoirsare justified in order to calibrate the permeability-thick-ness (KH) with logs. Despite intensive data collectionand analysis, uncertainties in prediction of porosity andpermeability remain, resulting in wide ranges of recov-erable reserve estimates for discoveries in the deep-water Wilcox trend.

The current deep-water Wilcox appraisalapproach within Chevron involves co-location of spe-cialists in petrology, formation evaluation, staticmodeling, dynamic modeling, completions, and artifi-cial lift. Decision analysis occurs at a higher butinteractive level in order to aid the team in efficientlycharacterizing uncertainties. Integration of these disci-plines and co-location of experts from various parts ofChevron have resulted in a high performance dynamicteam that is better able to tackle the challenges of thedeep-water Wilcox play.



Wilcox Depositional Architecture in the Gulf of Mexico Basin: A Framework for Improving Deep Water Exploration and Reservoir Risk

Fillon, Richard H.Earth Studies Group 3730 Rue Nichole New Orleans, Louisiana [email protected]

AbstractThis study presents a revised Gulf of Mexico

Basin chronology for the Paleogene based on depth vs.age graphic correlation of biostratigraphic event datafrom over 200,000 wells using a new Paleogene stan-dard timescale. This places Gulf of Mexico Wilcoxstrata in the interval between 61.4 Ma and 51.0 Ma rela-tive to the new time scale and provides high resolutionregional stratigraphic control necessary for investigat-ing the causes of apparent heterogeneity in deep waterWilcox age reservoirs. It brings turbidite sectionrecorded at the deep water Baha boreholes located inthe southeastern Alaminos Canyon protraction area intoclose agreement with important features of basin mar-gin Wilcox stratigraphy. Lower Wilcox seafloor

drainage axes are identified using GIS-based geomor-phic analysis of a chronostratigraphically defined,isostatically restored basin surface. The identification ofbasin drainage systems reveals links between potentialsediment sources in ancestral river drainages tributaryto the Gulf of Mexico and deep basin fan systems. Thisallows assessment of relative detrital contributions fromdifferent source areas for any location in the basin. Sur-face gradients on the restored lower Wilcox seafloormay reflect the syndepositional distribution of energy atthe seabed, related to bedforms, grain size and sorting,and may provide clues to the variable results of deepwater Paleogene discoveries.



Cenozoic Kinematics and Dynamics of Oblique Collision Between two Convergent Plate Margins: The Caribbean-South America Collision in Eastern Venezuela, Trinidad and Barbados

Pindell, JamesTectonic Analysis, Ltd.Chestnut House, Burton ParkDunctonGU28 0LHUK

andDepartment of Earth ScienceRice UniversityHouston, Texas [email protected]

Kennan, LorcanTectonic Analysis, Ltd.Chestnut House,Burton Park,DunctonGU28 0LHUK

AbstractNumerous structural, tectonic, and geometric

aspects of the eastern South Caribbean plate boundaryzone are assessed or reassessed in the light of seismicreflection data, field studies from 2000-2007, heavymineral analysis, updated interpretation of seismictomography, seismicity, GPS data, and refined platekinematic constraints for the Cenozoic. We show thatthe Cretaceous passive margin of northern South Amer-ica was transformed to a north-facing, slowlyconvergent margin in the late Maastrichtian, and that thecollision between the Caribbean and South Americawas a collision of two convergent margins above anintervening, “doubly subducting” proto-Caribbean oce-

anic lithosphere. The new assessments are iterativelyintegrated to create semi-quantitative palinspasticreconstructions for 5, 10, 25, 31, and 42 Ma, on whichpaleogeographies are developed. The origin of keysandstone units are considered, due to their importanceas major reservoirs, as well as the implications of thekinematic and dynamic modeling for structural timing.The primary collision between the two plates was com-pleted by 10 Ma; subsequent motion was essentiallyeast-west strike slip; and the deformations were drivenmainly in a bow-wave model of transcurrent simpleshear.



Paleogene Slope Deposits; Examples from the Chaudiere, Pointe-a-Pierre and San Fernando Formations, Central Range, Trinidad

Vincent, HasleyWach, GrantDepartment of Earth SciencesDalhousie UniversityRoom 3006 Life Sciences CentreHalifax, Nova ScotiaB3H 4J1, [email protected]

AbstractVarious interpretations have been proposed for deposi-tional environments in the Trinidad-Eastern Venezuela area during the Paleogene, most without supporting sedimentological evidence. We describe lithofacies in the Chaudiere, Pointe-a-Pierre, and San Fernando for-mations, which suggest that sediment gravity flows were the primary delivery mechanism for the coarse-grained clastics and carbonates that characterize these formations. Outcrop examples of soft sediment defor-mation, block slides, and floating boulders attest to sediment instability along over-steepened gradients,

consistent with a slope environment. Other common facies characteristics include low and high density tur-bidites and amalgamated channel fills, but there is no evidence for shallow-water reworking of sediments. The reinterpretation of a late Eocene outcrop highlights the need to resolve depositional processes along with biostratigraphy, as estimates of water depths based solely on paleontology may be underestimated. This has implications for Paleogene paleogeographic recon-structions.



Reducing Geologic Risk in Frontier Deep Water Exploration of the Paleogene, Suriname, South America

Kean, Allan

Brisson, Ignacio

Preston, Chuck

Colmenares, Julio

RepsolYPF

2001 Timberloch Place, Suite 4000

The Woodlands, Texas 77380

Connolly, David

dGB-USA

1 Sugar Creek Center Blvd, Suite 935

Sugar Land, Texas 77478

Sikora, Paul

Energy & Geoscience Institute,

University of Utah

423 Wakara Way, Suite 203

Salt Lake City, Utah 84108-1210

Legarretti, Leonardo

Patagonia Exploración S.A

Montañeses 2180, piso 4

Buenos Aires 1428

Argentina

Duddy, Ian

Geotrack International

37 Melville Road

Brunswick West

Victoria 3055

Australia

Pindell, James

Kennan, Lorcan

Tectonic Analysis, Ltd.

Chestnut House, Burton Park

Duncton, GU28 0LH

UK

Odegard, Mark

Grizzly Geosciences

14019 SW Freeway, Suite 301-735

Sugar Land, Texas 77478

Hossein, Hank

Humble Geochemical Services

P.O. Box 789

Humble, Texas 77347

Armentrout, John

Cascade Stratigraphics Inc.

20060 SE Highway 224

Damascus, Oregon 97089

Introduction

Exploration in frontier areas involves makinginterpretation based on little to no geological and geo-physical (G&G) data; the enduring lack of data is whatdefines an area as frontier. The data must be extrapo-lated a long way to build a prospect, and in order tojustify the drilling of a single well with costs that canbe in excess of $30 million, it becomes important toaddress geologic and geophysical risk. This increasesthe probability of success through the application ofscience and the integration of different disciplines andtechnologies and the development of a consistent storyfor our recommendations. We need to address the geo-

logic and geophysical risks associated with specificareas and prospects to determine where best to spendour time, energy, and resources and to determine whatfurther studies are suited to this risk reduction.

This paper is based on RepsolYPF’s efforts tomaximize the probability of geological and geophysi-cal (PG&G) success for a frontier exploration projectin the offshore deepwater area of Suriname, northeast-ern South America (Fig. 1). The project is ongoing andthis is an update of our approach to evaluating an areapre-drill. Pre-drill, one’s interpretation is still valid;post-drill is where the real story is revealed.


Development of the Colombian Andes and Caribbean Regions at the Interface between the South American, Caribbean, and Nazca Plates

Gomez, ElíasButcher, GeoffStewart, DaveShell International Exploration and Production Inc.200 North Dairy AshfordHouston, Texas [email protected]

AbstractThe north/northeast-striking Central Cordillera

of Colombia is a major tectonic element in northwestSouth America that is flanked by two sedimentary-basin systems. To the east, a back-arc foreland-basinsystem extends from the Middle Magdalena Valleybasin to the Llanos basin across the now uplifted East-ern Cordillera region. The marginal trench along thewestern side of the Central Cordillera evolved intoforearc basins and fringing accretionary fold belts inthe Lower Magdalena Valley basin and the Caribbean

offshore. In this paper, we integrate recent evaluationsfrom the Andes and Caribbean regions of Colombiaand summarize the chronologies of geologic events thatled to the formation of this complex convergent-margingeodynamic system. In general, such chronologies fitpublished models of Late Cretaceous-Cenozoic west-east movement of the Caribbean plate relative to SouthAmerica, and Neogene west-east subduction of theNazca plate underneath South America.



Differing Structural Trends of Oligocene and Miocene Tectonic Events, Northern Putumayo Basin, Colombia: Implications for Petroleum Exploration

Villamil, TomasVásquez, CésarBolaños, AlixC&C Energy GroupCarrera 4 No. 72-35 Suite 800Bogotá, [email protected]

Abstract3D seismic data acquired in 2007 in the northern

Putumayo foothills, along the transition zone betweenthe leading edge of the thrust belt and the basin, allowsevaluation of the structural configuration and tectonictransport directions of the Oligocene and Miocenedeformation events, and of the clear obliquity betweenthem. Oligocene tectonic transport was towards theeast, having an azimuth between 90° and 95°, andfaults were oriented north-south (0° to 5° azimuth). TheOligocene deformation front was a thrust belt of multi-ple stacks, faults are relatively high-angle (30°-35°dip), and they involve the basement. The tectonic trans-port of the Miocene Andean Orogeny in this region wastowards the southeast (azimuth of 130° to 140°); faultsare of higher angle and may detach deeper within the

basement. There was stratigraphic evidence suggestingthat some of these faults might be reactivated exten-sional features. Miocene deformation wascharacterized by forward-breaking reverse faults andmonoclinal tilting of the foredeep as in a triangle zone.The cause of this tilting could not be seen on seismicdata but could be related to propagation of the tip of atriangle zone wedging somewhere within the basement.Most Andean Orogeny traps were breached and 1Dbasin modeling suggested that they were not chargedbecause of timing of migration was younger than tim-ing of Miocene trap formation. Some Oligocene trapswere breached by the Miocene orogeny but some werenot; these constitute the primary targets for petroleumexploration in the area.



Dextral Shear, Terrane Accretion and Basin Formation in the Northern Andes: Explained only by Interaction with a Pacific-Derived Caribbean Plate

Kennan, Lorcan

Tectonic Analysis Ltd.

Chestnut House

Duncton

West Sussex

GU28 0LH

UK

[email protected]

Pindell, JamesTectonic Analysis, Ltd.Chestnut House, Burton ParkDunctonGU28 0LHUKandDepartment of Earth ScienceRice UniversityHouston, Texas 77002USA

AbstractPacific-origin models for the Caribbean Plate

imply strong Cretaceous interaction with the northernAndes, and this is reflected in regional structure,stratigraphy and magmatic history. Intra-Americanmodels for the origin of the Caribbean Plate do notimply this interaction and cannot explain the dramaticcontrasts in Cretaceous orogenesis and magmatismbetween the northern Andes (Ecuador, Colombia) andthe central Andes (central Peru to Bolivia). In thispaper we summarize the contrasts between the North-ern and Central Andes, focusing on fault offsets,magmatic history, and dated history of uplift, unroofingand erosion. The Central Andes show persistent largemagnitude subduction and more or less continuous arcmagmatism. Associated deformation is dominantlycompressional or extensional, without significantstrike-slip offsets, all related to more or less head-onrelatively rapid subduction of the Farallon Plate. TheFarallon Plate was also subducted beneath the PanamaArc at the rear of the Caribbean Plate. In contrast, theNorthern Andes shows a protracted history of accretionof oceanic plateau basalt and island arc terranes, com-

bined with large magnitude dextral shear, without largemagnitude subduction and associated arc magmatism.All the accreted terranes have a distinctive CaribbeanPlate geochemical character. Regional plate reconstruc-tions clearly show that the Caribbean Plate originatedin the eastern Pacific. A tight fit against northwesternSouth America and southern Mexico clearly impliesthat the Northern Andes deformation was caused bynorthward migration of the Caribbean Plate. The age ofassociated intense dextral shear is well constrained tothe interval 100-40 Ma, and these deformation eventsare never seen in the Central Andes. As late as Eocenetime, the triple junction between South America, theCaribbean, and the Farallon Plate, where the Panamaarc joined western South America, was located west ofEcuador, and strike-slip pull-apart basins such as theTalara, Tumbes and Manabi Basins directly relate tothe northward migration of the triple junction. Featuresassociated with the subduction of the Nazca Plate onlyestablish themselves in Ecuador, and then Colombia, asthe triple junction migrates.



Laramide Deformation in the Burgos Basin, Northeastern Mexico

Eguiluz-de Antuñano, SamuelConsultant Geologist197 Slade LaneManchesterM19 2 [email protected]

AbstractLaramide deformation is represented in strati-

graphic sequences and structures in the Burgos Basin.Paleontological data support the continued eastwardmigration of siliciclastic facies in space and time fromthe western central Mexican basin at Zacatecas to theeastern Burgos Basin at Tamaulipas. In the BurgosBasin, Paleocene and Eocene Wilcox deposits are third-order sequences which may be controlled by eustaticsea level changes from 60 Ma to around 49 Ma. Overly-ing the upper Wilcox and lower Reklaw deposits, aregional deeply erosive surface has a suggested agearound 48.5 Ma; above this unconformity a progradingwedge complex having a TST (upper Reklaw deposit)is identifiable. The Queen City, Weches-Cook Mountainand lower Yegua (Crockett) deposits are also third-ordersequences from 48.5 to around 39.5 Ma, inferred to becontrolled by eustasy and synsedimentary growth faults.

A new deeply erosive surface developed around39.5 Ma. Above this submarine unconformity, the mid-dle and upper Yegua were deposited and representanother prograding wedge complex having a high sedi-mentary rate ( 280 m/Ma). In the surface andsubsurface of the Burgos Basin, the folded Paleocene-Eocene rocks strike north-northwest/south-southeast asa result of Laramide deformation. Isotopic and struc-tural data in the Sabinas Basin support the idea thatboth unconformities (at base upper-Reklaw and at basemiddle-Yegua) are related to uplift and denudation inwestern continental areas and have been producedmainly by tectonic mechanisms, during progressivepulses of the Laramide uplift of the Sierra Madre Ori-ental and fold belt of the Sabinas Basin. The youngerFrio sequence belongs to another tectonic event, dis-crete from the Laramide uplift.



Impact-Induced Sediments at the K-T Boundary: Offshore Campeche and Chiapas-Tabasco Region, Southeastern Mexico

Grajales-Nishimura, J.M.

Coordinación de Exploración

Instituto Mexicano del Petróleo

México, D.F.

[email protected]

AbstractAn important carbonate breccia interval repre-

sents a significant portion of the Cretaceous-Tertiary(K-T) boundary sedimentary succession accumulatedunder deep-water conditions in the western part of theYucatan platform, offshore Campeche, during theChicxulub impact event. The K-T boundary sedimen-tary succession is located approximately 300 kmwestward from the center of the Chicxulub structure.This sedimentary succession consists of a single gradeddeposit subdivided into three main units that from baseto top includes: (1) a basal 50 to 300 m-thick, coarse-grained carbonate breccia; (2) a 10 to 20 m-thick, fine-grained carbonate breccia, and; (3) a 25 to 30 m-thick,interval of sand and silt to clay-sized constituents,mostly abundant ejecta material. Additionally, a 10-20m-thick, fine-grained calcareous breccia is recognizedwithin the ejecta material-rich layer (unit 3) in somewells. The K-T boundary sedimentary succession isbounded at its base by a deep-water, shaly-calcareousfacies of Upper Maastrichtian age and at its top by sim-ilar rocks of lower Paleocene age. Similarsedimentological characteristics and stratigraphic rela-tionships are observed in analog outcrops in the Sierrade Chiapas (El Guayal, State of Tabasco; and Bochil,Chilil and Soyaló, State of Chiapas). Lithoclasts of thecalcareous breccias are derived dominantly from plat-

form-interior and platform-margin environments andonly a few from deep-water settings. Ejecta material inunit 3 includes: shocked quartz, quartz with ballenstructure, shocked plagioclase, altered melt rock, andrare pelitic schist fragments. Wireline log data, distri-bution, and stratigraphic relationships indicate a base-of-slope apron geometry for the thick carbonate brecciadeposit.

The stratigraphic architecture and distribution ofimpact material within the K-T boundary sedimentarysuccession suggest the following sequence of eventsand products that probably occurred within a very shorttime span following the Chicxulub impact:

1. Unusually strong seismic shaking induced thecollapse of the platform margin, resulting in anenormous debris flow (units 1 and 2),

2. Arrival and deposition of ballistic impact ejecta(unit 3), and

3. Reworking and deposition, possible induced bytsunami currents (carbonate breccia within unit.

Units 1 and 2 represent the most important oilreservoirs at the Campeche Bay oil fields, and unit 3 isthe seal layer. Unit 4 is a dark clay bed deposited dur-ing a global decrease in ocean productivity followingthe meteorite impact.



Thermal Maturation History of the Wilcox Group (Paleocene-Eocene), Texas: Results of Regional-Scale Multi-1D Modeling

Rowan, E.L.U.S. Geological Survey956 National CenterReston, Virginia [email protected]

Warwick, P.D.U.S. Geological Survey956 National CenterReston, Virginia 20192

Pitman, J.K.

U.S. Geological Survey

P.O. Box 25046

Lakewood, Colorado 80225

AbstractThe thermal maturation history of the Paleocene-

Eocene Wilcox Group has been reconstructed based onburial history models of 53 wells in the Texas coastalplain. This modeling study has been conducted in con-junction with a geologically based assessment of the oiland gas resources in Cenozoic strata of the Gulf ofMexico coastal plain and state waters. In the onshoreTexas coastal plain, coals and organic-rich shales, pre-dominantly of terrestrial origin, within the WilcoxGroup are the primary source of oil (Wenger et al.,1994) as well as a source of gas. The Wilcox, however,is modeled as a single unit, without subdivision intosource rock and non-source rock intervals.

Generation of oil from Type III kerogen withinthe Wilcox Group is modeled using hydrous pyrolysisreaction kinetic parameters (Lewan, M.D., writtencommunication, 2006). Gas generation from Type IIIkerogen is represented using calculated Ro values. Themodels are calibrated with bottom hole temperature

(BHT), and vitrinite reflectance (Ro %) data for theWilcox Group. Ro data from near-coastal sites havebeen selected to minimize the possible effects of upliftand erosion and then composited to give a regional Ro-depth trend.

Model calculations for the study area, theonshore Texas coastal plain, indicate that downdip por-tions of the basal Wilcox had reached sufficient thermalmaturity to generate hydrocarbons by early Eocene(~50 Ma). This relatively early maturation is explainedby rapid sediment accumulation in the early Tertiarycombined with the reaction kinetic parameters used inthe models. Thermal maturation increases through timewith increasing burial depth and temperature, graduallymoving the maturation front updip. At present day,hydrocarbon generation is complete in the downdipWilcox within the study area but is currently ongoingin the updip portions of the formation.



Margin Tectonics: Passive Continental Margins Migrating Basinward

Lowrie, AllenConsultant238 F. Z. Goss RoadPicayune, Mississippi [email protected]@navy.mil

Jenkins, Linda

Consultant

2403 Hillsdale Road

Picayune, Mississippi 39466

USA

[email protected]

Abstract A review of the basic structure of passive conti-

nental margins suggests that their general movementalong the margin is down slope and basinward. In thecase of the northern Gulf of Mexico, the continentalmargin extends from the fall line at Little Rock, Arkan-sas, to the Gulf’s abyssal plain. This margin representsan overall dip-oriented lateral distance of some 10degrees latitude, circa 1200 km. It descends from conti-nental elevations of ca. 500 m to submarine depths ofgreater than 3 km.

As the rifting basin rapidly evolved during thetectonic subsidence phase, various rifted basementblocks have subsided and rotated basinward and seaf-loor spreading and plate tectonics have determinedsubsidence rates. Tectonic motions within the overlyingsediment cover are primarily extensional, as shown bylistric faulting. Localized compression occurs at the

foot of the listric faulting. Dynamic migration of shaleor salt serves as a “tectonic escape” moving basinwardand down slope. These motions range from marginspanning, to regional, to local, to microscopic; themotions occur on time scales varying from instanta-neous to geologically slow.

The second-order sedimentary units, determinedfrom sequence and seismic stratigraphy, record charac-teristics of the deposition itself. The sediments atpresent occur at greater depths in the subsurface thantheir original site of deposition as a result of subsidenceand lateral migration.

This paper suggests that “margin tectonics”along passive continental margins cause general downslope movements of debris, due to both subsidence andlateral motion.

Author Index A-1

Author Index

AAdams, Stephen D., 15Anderson, Lynn E., 2Armentrout, John, 25

BBerman, Arthur E., 13Bolaños, Alix, 27Brisson, Ignacio, 25Butcher, Geoff, 26

CClinch, Simon, 20, 21Coleman, James L., 1Colmenares, Julio, 25Connolly, David, 25Connors, Christopher D., 16Cossey, Stephen P.J., 12

DDenne, Richard A., 8Duddy, Ian, 25Dull, Kathy, 4

EEguiluz-de Antuñano, Samuel, 29Ellwood, Brooks B., 9

FFiduk, Joseph C., 2Fillon, Richard H., 9, 22

GGalloway, William E., 10Gomez, Elías, 26Grajales-Nishimura, J.M., 30

HHackley, Paul C., 1Hayba, Daniel O., 1Hossein, Hank, 25

JJenkins, Linda, 32

KKarlsen, Alexander W., 1, 18Kassab, Ahmed, 9Kean, Allan, 25Kennan, Lorcan, 6, 23, 25, 28

LLegarretti, Leonardo, 25Lewis, Jennifer, 20, 21Lowrie, Allen, 32

MMatava, Tim, 17Mentemeier, Sam, 4Meyer, Dave, 20, 21Moon, Jerry, 16, 17Mount, Van, 4

OOdegard, Mark, 25

PPindell, James, 6, 23, 25, 28Pitman, J.K., 31Powell, Timothy, 15Preston, Chuck, 25Pulham, Andrew J., 2

RRadovich, Barbara, 16, 17Richards, Matt, 20, 21Rosen, Rashel N., 7Rosenfeld, Joshua H., 13Rowan, Elisabeth L., 1, 31

SSchultz, Thomas R., 2Seitchik, Adam M., 15Sikora, Paul, 25Skirius, Christine, 20, 21Stewart, Dave, 26Stokes, Ron, 20, 21Sullivan, Robert, 15Swanson, Sharon M., 1, 18

A-2 Author Index

VVásquez, César, 27Villamil, Tomas, 27Vincent, Hasley, 24

WWach, Grant, 24

Warwick, Peter D., 1, 18, 31Waterman, Arthur S., 9Winker, Charles D., 19

ZZarra, Larry, 5, 20, 21

the paleogene of the gulf of mexico and caribbean basinsthe paleogene of the gulf of mexico and...

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