20 th annual williston basin petroleum conference
Post on 24-Feb-2016
47 Views
Preview:
DESCRIPTION
TRANSCRIPT
20th Annual Williston Basin Petroleum Conference
Russ BuettnerBakken Asset Team Subsurface Manager
Marathon Oil Corporation
Bismarck, North DakotaMay 23rd, 2012
Understanding Vertical & Horizontal Communication in the Bakken
AgendaHighlight Marathon’s Bakken results
Why are we focused on lateral and vertical communication?
Marathon’s Data Acquisition Overview
Observations that indicate communicationDuring both stimulation and production
Key data and analysis used to construct reservoir models
Calibrated simulation results that provide insight toward oil recovery potential
Invitation to Collaborate2
3
Striving for Performance Improvement
2008 2009 2010 20110
100
200
300
400
500
600
Gro
ss E
UR
(MBO
E)
Marathon Oil Corporation
2007 2008 2009 2010 20110
5
10
15
20
25
30
35
Frac Fluid (BBL/Ft)Stages (#)Proppant Density (x 10 lb/ft)
Souce: NDIC database
Completion Practices (1,600 wells)*MRO Per Well EUR by Year
0 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,0000
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90 Day Cum Oil (BBL)
Tota
l Fra
c Fl
uid
(MBB
L)
MRO Per Well Avg IP by Year
90 Day Cum Oil vs Frac Fluid*
* Source: NDIC database
2008 2009 2010 20110
200
400
600
800
1000
1200
BOPD
Industry
Recovery improvements have been made….but do we understand fundamentally why?
0 50,000 100,000 150,000 200,000 250,0000
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
12 Month Cumulative Oil Production (BBL)
Cum
ulati
ve D
istrib
ution
Fun
ction
2006 – 2011 Dunn County Middle Bakken Wells
Open Hole
6 Stage Completion
9 Stage Completion
19 Stage Completion
20 Stage Completion
Mean 12 Month Cumulative
Oil Production
(BBL Oil)
41,000 45,000 59,000 88,000 91,000*
2006 – 2007 Open Hole Wells
2008Staged Wells
2009Staged Wells
2010Staged Wells
2008 Stage Completion WellsAverage # of Stages: 6Average Proppant Density (lb/ft): 144
2009 Stage Completion WellsAverage # of Stages: 9Average Proppant Density (lb/ft): 171
2006 – 2007 Open Hole Completion WellsAverage Proppant Density (lb/ft): 71
2010 Stage Completion WellsAverage # of Stages: 19Average Proppant Density (lb/ft): 2682011
Staged Wells2011 Stage Completion WellsAverage # of Stages: 20Average Proppant Density (lb/ft): 228
2011 staged wells cumulative oil production based on extrapolation.
Why do more stages improve performance?-More uniform stimulation along the lateral-Increased Stimulated Rock Volume-Connections to bounding layers?
5
What is the potential of the Entire Bakken section?
Geologic Layers
Estimated STOOIP, MMBLS
Lodgepole 7 - 9
Upper Bakken Shale
4 - 8
Middle Bakken
8 – 12
Lower Bakken Shale
12 – 15
Three Forks 10– 15
Oil in place in at Typical 1280 acre DSU
• 5-15% RF of MB or TF is what we attribute to a development unit
• But is recovery limited to the horizon that the lateral is landed in?
40-60 MMBbls
6
Conceptual Single Well Recovery of All geologic layers vs. MB only
• All geologic layers are connected through the natural fracture and fault network
• Vertical drainage is more dominant than lateral
• Well EUR40 : 900 – 1,100 MBOE
• Geologic barriers between MB and TF and no drainage of bounding shales
• Lateral drainage is dominant
• Well EUR40 : 300 - 500 MBOE
High Side - Full Vertical Communication Low Side - Vertical Barriers constrain drainage to MB only
5,280ft 5,280 ftLimited areal drainagewith increased vertical connectivity
Broad areal drainagewith no vertical connectivity
Geocellular model based simulation with dual porosity and discrete fracture network
Model cross-section
UBSMBLBSTF
MB
7
• Geologic barriers between MB and TF. No recovery from shales
• Total wells per DSU: 3 MB + 3 TF
• DSU EUR40 : 2 – 3.5 MMBOE • MB Well EUR40: 200- 300 MBOE
• Geologic barriers between MB and TF. No recovery from shales
• Total wells per DSU: 5 MB + 5 TF
• DSU EUR40 : 3 – 4.5 MMBOE• MB Well EUR40: 150- 250 MBOE
Conceptual Full Development - What is Optimum Spacing?
• All geologic layers are connected through fracture networks
• Total wells per DSU: 3 MB + 3 TF
• DSU EUR40 : 4 - 6 MMBOE • MB Well EUR40: 700 – 1,000 MBOE
Full Vertical Communication Vertical Barriers
Optimum spacing depends on the degree
of vertical drainage
MB
TF
8
Bakken Data Acquisition & Integration
Core Facies DescriptionsSequence Stratigraphy Model
Petrophysics Core fracture descriptions
Fracture intensity[FI], orientation, relaxed apertures, morphology, kinematics
Borehole image logs Fracture counts, orientations, apertures, in-situ stress
Geophysics 3D/3C surface seismic
VSP (ZO,WA,FO) & MicroseismicLineaments
Grav & Mag attributes Surface Data (Landsat, Digital Elevation Model, etc)
GeochemistryRocks & Fluid Samples
Production Data (Pre- & Post-Stimultation)In-Situ Stress (Vertical DFIT/FET, Pp, Shmin)
Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers in Vertical & Horizontal Wells)SCAL & Geomechanics
Multiple Plug Orientations, Dynamic & Static Elastic Properties (Anisotropy & Tensors)
Failure Data (MCFE)Permeabilities
Core Facies Descriptions& Petrophysics
9
Bakken Data Acquisition & Integration
Core Facies DescriptionsSeq-Strat Model, Facies definition for mapping & modeling
Petrophysics Core fracture descriptions
Fracture intensity, orientation, aperture descriptionBorehole image logs
Fracture counts, orientations, apertures, in-situ stress Geophysics
3D/3C surface seismicVSP (ZO,WA,FO) & Microseismic
Lineaments Grav & Mag attributes
Surface Data (Landsat, Digital Elevation Model, etc)GeochemistryRocks & Fluid Samples
Production Data (Pre- & Post-Stimultation)In-Situ Stress (Vertical DFIT/FET, Pp, Shmin)
Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers in Vertical & Horizontal Wells)SCAL & Geomechanics
Multiple Plug Orientations, Dynamic & Static Elastic Properties (Anisotropy & Tensors)
Failure Data (MCFE)Permeabilities
Example of Core Description Vertical Core : Natural Fracture Intercept Rate
(Fracture counts) & Fracture Morphology
Horizontal Core
Fracture intensity
10
Bakken Data Acquisition & Integration
Core Facies DescriptionsSeq-Strat Model, Facies definition for mapping & modeling
Petrophysics Core fracture descriptions
Fracture intensity[FI], orientation, relaxed apertures, morphology, kinematics
Borehole image logs Fracture counts, orientations
Geophysics 3D seismic & VSP’s
MicroseismicLineaments
Grav & Mag attributes Surface Data (Landsat, Digital Elevation Model, etc)
GeochemistryRocks & Fluid Samples
Production Data (Pre- & Post-Stimultation)In-Situ Stress (Vertical DFIT/FET, Pp, Shmin)
Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers in Vertical & Horizontal Wells)SCAL & Geomechanics
Multiple Plug Orientations, Dynamic & Static Elastic Properties (Anisotropy & Tensors)
Failure Data (MCFE)Permeabilities
Horizontal Image Logs & 3DFracture Corridors from Seismic
(curvature calibrated to image Log)
11
Bakken Data Acquisition & Integration
Core Facies DescriptionsSeq-Strat Model, Facies definition for mapping & modeling
Petrophysics Core fracture descriptions
Fracture intensity[FI], orientation, relaxed apertures, morphology, kinematics
Borehole image logs Fracture counts, orientations, apertures, in-situ stress
Geophysics 3D/3C surface seismic & VSP’s
MicroseismicLineaments
Grav & Mag attributes Surface Data (Landsat, Digital Elevation Model, etc)
GeochemistryRocks & Fluid Samples
Production Data (Pre- & Post-Stimultation)In-Situ Stress (Vertical DFIT/FET, Pp, Shmin)
Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers in Vertical & Horizontal Wells)SCAL & Geomechanics
Multiple Plug Orientations, Dynamic & Static Elastic Properties (Anisotropy & Tensors)
Failure Data (MCFE)Permeabilities
12
Bakken Data Acquisition & Integration
Core Facies DescriptionsSeq-Strat Model, Facies definition for mapping & modeling
Petrophysics Core fracture descriptions
Fracture intensity[FI], orientation, relaxed apertures, morphology, kinematics
Borehole image logs Fracture counts, orientations, apertures, in-situ stress
Geophysics 3D/3C surface seismic
VSP (ZO,WA,FO) & MicroseismicLineaments
Grav & Mag attributes Surface Data (Landsat, Digital Elevation Model, etc)
GeochemistryCore , Cuttings & Produced Fluid Samples
Production Data (Pre- & Post-Stimultation)In-Situ Stress (Vertical DFIT/FET, Pp, Shmin)
Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers in Vertical & Horizontal Wells)SCAL & Geomechanics
Multiple Plug Orientations, Dynamic & Static Elastic Properties (Anisotropy & Tensors)
Failure Data (MCFE)Permeabilities
13
Bakken Data Acquisition & Integration
Core Facies DescriptionsSeq-Strat Model, Facies definition for mapping & modeling
Petrophysics Core fracture descriptions
Fracture intensity[FI], orientation, relaxed apertures, morphology, kinematics
Borehole image logs Fracture counts, orientations, apertures, in-situ stress
Geophysics 3D/3C surface seismic
VSP (ZO,WA,FO) & MicroseismicLineaments
Grav & Mag attributes Surface Data (Landsat, Digital Elevation Model, etc)
GeochemistryRocks & Fluid Samples
Production Data (Pre- & Post-Stimultation)In-Situ Stress (DFIT/FET)
Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers in Vertical & Horizontal Wells)SCAL & Geomechanics
Multiple Plug Orientations, Dynamic & Static Elastic Properties (Anisotropy & Tensors)
Failure Data (MCFE)Permeabilities
Marathon Mylo Wolding 14-11H Middle BakkenMinifrac - G Function
10 20 30 40 50 60 70
G(Time)
8000
8100
8200
8300
8400
8500
8600
8700
8800
8900A
0
100
200
300
400
500
600
700
800
900
1000D
(0.002, 0)
(m = 11.42)
(64.54, 737.3)
(Y = 0)
Bottom Hole Calc Pressure (psi)Smoothed Pressure (psi)Smoothed Adaptive 1st Derivative (psi)Smoothed Adaptive G*dP/dG (psi)
AADD
1
1 Closure
Time41.90
BHCP8303
SP0.000
DP0.000
FE0.000
GohWin v1.6.511-Jul-10 03:23
14
Bakken Data Acquisition & Integration
Core Facies DescriptionsSeq-Strat Model, Facies definition for mapping & modeling
Petrophysics Core fracture descriptions
Fracture intensity[FI], orientation, relaxed apertures, morphology, kinematics
Borehole image logs Fracture counts, orientations, apertures, in-situ stress
Geophysics 3D/3C surface seismic
VSP (ZO,WA,FO) & MicroseismicLineaments
Grav & Mag attributes Surface Data (Landsat, Digital Elevation Model, etc)
GeochemistryRocks & Fluid Samples
Production Data (Pre- & Post-Stimultation)In-Situ Stress (Vertical DFIT/FET, Pp, Shmin)
Stimulation (Anomalous Stages, Inter-well Connectivity, Tracers in Vertical & Horizontal Wells)
Special core analysisGeomechanical rock properties
Matrix Permeabilities from whole core Sh
ear S
tres
s (ps
i) In
crea
ses
Normal stress (psi) Increases
15
Increased well density Preparing for and observing lateral communication during fracs Decompleting offset wells during fracs
Probable fracture corridors interpreted from gas shows and structure maps
Seismic is also helpful in detecting larger structural events
Curvature Map Suggestive of Natural Fracture Density
High Natural Fracture Density
AssumedN
Natural FractureInterpreted
Low Natural Fracture Density
Assumed
Gas Profile for Frac’d LateralOffset Lateral Distances to Frac’d Lateral
Fracture Corridor
“Probable” Fracture Corridors
2000’ Radius3000’ Radius
~50% of Near offset
decompleted wells
see pressure from offet
stimulation treatments
Structure from well data
Infill Wells
16
Completion Interference: Three Forks to Middle Bakken
Casing pressure in a Middle Bakken well increased from 75 to 3000 psi during stimulation of adjacent TF well
Pressure increases correlated with stages located in areas with high gas shows in the lateral
Three Forks Frac Pressures Up Offset MB Well Via Fracture Corridors?
Three Forks Lateral
Middle Bakken Lateral
Fracture Corridors
700’
Three Forks Lateral Stage Number
Middle Bakken Casing Pressure
Middle Bakken Well
Middle Bakken Well
Three Forks Well Three Forks Well
Infill wells
17
Production Interference – Middle Bakken interferes with Three ForksVertical Communication Occurs Through Natural Fractures?
Lodgepole
Upper Bakken Shale
Middle Bakken
Three Forks
Lower Bakken Shale
Middle Bakken well Three Forks well
Three Forks wellProduction communication
Middle Bakken wellPump installation
Middle Bakken well
Three Forks well
Three Forks well
Middle Bakken well
500 ft 250 ft
Instantaneous production interference
between nearby MB and TF wells
Horizontal Core Vertical Fractures in a Horizontal Cores
Horizontal Core Slab revealed intense fabric of micro-fractures
Wide aperture fluorescing fractures in intact core
Slabbed Core
Core Depth Increases
Core Depth Increases
18
19
Outcrops and Conceptual fracture models help explain communication observed in the field
₋ Fractures related to faults can penetrate geologic units
₋ Vertical drainage through fault related fractures should be expected
General outcrop display– not Middle Bakken
Bed contained fractures
Integrating natural fractures into a 3 dimensional geocellular model
20
-Description of pervasive micro-fracture network
Characterization and understanding of all fractures both natural and induced is needed
to predict performance
- Description of Regional Fractures
-Inclusion of structurally related fractures (swarms-corridors)
Independent Fracture properties are included in a
dual porosity simulation.
Regional Fractures
Structural Fractures ShMax
21
Vertical Stress and Hydraulic Fracture ModelIntegrating field data to understand fracture growth
• Vertical stress and pore pressure in 5 layers (LP, UBS, MB, LBS and TF) were measured with DFIT tests
• Results used as inputs to hydraulic fracture simulation models
• Note marginal differences in pore pressure in each layer that also suggests that the layers are in communication
Predictive fracture models indicate containment of fracs within zone
• The created Xf that can exceed 1,000’, but the effective, propped fracture half-lengths are <200’
• Model does not include natural fracture description that can divert fracture growth vertically
10550
10575
10600
10625
10650
10675
10700
7500 9500
DEPT
H, ft
PSI
Closure Pressure
Pore Pressure
INCREASING
INCR
EASI
NG
LP
TF
MB
22
Geochemical Data - Stratigraphic intervals in the Bakken Petroleum System have unique geochemical fingerprints
-30.5 -30 -29.5 -29
10,500
10,525
10,550
10,575
10,600
10,625
10,650
10,675
10,700
10,725
10,750
Geochemical Signature
• Geochemical signature values can be sampled initially and over time
• Fluctuation would be indicative of contribution from bounding layers
23
Individual Well Reserve Evaluations – Which b-factor?Decline analysis also suggests vertical communication is occuring
0.0
1.0
2.0
3.0
4.0
5.0
1 10 100 1000 10000
b-parameter
Time, days
b-parameter vs. Time, days
0.0
1.0
2.0
3.0
4.0
5.0
1 10 100 1000 10000
b-parameter
Time, days
b-parameter vs. Time, days
Full vertical communication
• In this model, geologic units are connected vertically through fracture networks
• Simulation indicates that b-factors would stabilize near 2.
Vertical barriers between layers
• With no vertical communication between layers in the model
• Simulation indicates that b-factors will stabilize at around 1.0 (isolated MB well)
• This behavior is not being observed in areas studied
Well performance observations are between these two cases indicating partial vertical communication
24
Example - Calibrated Single Well Conceptual Model
• Vertical communication is modeled to occur through structurally related fractures• Vertical contribution is calibrated with geochemical based production allocation
• Propped hydraulic fractures are assumed to be contained in MB
• EUR40 : 600 -850 MBOE
Layer % Contribution Recoverable MBOE
Upper layers 5 - 15 50 - 100
MB 75 - 80 500 – 550
Lower layers 15 -20 100 - 200
History matching and geochem production allocation helps to understand how to constrain vertical
communication in the static model
Vertical Permeability resultingfrom fracture networks
Pressure depletion from a frac stage and through natural fractures
Challenge – How do we collaborate as developers of the Bakken to improve efficiency and oil recovery?
Acreage positions are secure in many areas
Sharing technical understanding and best practices will serve North Dakota and all of the Bakken stakeholders
25
URAN_MW_FORE_ENHANCE.UNSMRY 16 Jan 2012
Date (YEARS)
OilP
rod
Rate
(STB
/DAY
),OP
RH(S
TB/D
AY)
200
400
600
OPROPRH
URAN 31-2H
History Match - Oil Rate
30 years depletion
TF MB TF MB
Pressure (Fracture Grid)
Acknowledgments
Marathon Bakken Asset teamDoyle Adams Faisal RasdiAhmad Salman
Upstream Technology – Bakken Integrated Reservoir Characterization Team
Sebastian Bayer Steve Buckner Jason ChenPhillipe Lozano
26
top related