colloidal dispersion gels (cdg) and their … - eori... · colloidal dispersion gels (cdg) and...

T h e Sc i e n c e o f En h a n c e d O i l R e c o v e r y

The Science of Enhanced Oi l Recovery

E. Manrique & M. Lantz

Colloidal Dispersion Gels

(CDG) and Their Application

in Wyoming and Elsewhere

Jackson Hole, WY, September 12-13, 2011


• Introduction:

• What are CDGs (Colloidal Dispersion Gels)?

• CDG Development Review

• Summary of EOR & CDG projects in Wyoming

• Wyoming Tertiary Projects

• CDG Experience in Wyoming

• Recent Advances of Lab. & Simulation Studies

• CDG Experiences Elsewhere

• Field Experiences in Argentina and Colombia

• Closing Remarks

Outline


Introduction:

What are CDGs?

• CDGs can be considered similar to polymer flooding

• CDGs (weak gels) generate higher viscosities & RRF than

polymer solutions at lower concentrations

• HPAM are co-injected with Al-Citrate (crosslinker)

- Viscosity/inj. pressure build-up (gelation/retention)

• Very controversial topic!

- However, some lab results do not support field performances


Introduction:

CDG Development Review

• Phillips Petroleum first developed the “layered process”

which was first injected in 1980 in the North Burbank field

- Found sequential injection of HPAM / aluminum citrate (AlCit)

created higher RRF than straight polymer

• In an effort to quickly test the layered process in the lab,

TIORCO performed screen pack tests with mixed solutions

of low concentrations of HPAM and AlCit

• Found that the solution had no visible bulk gel characteristic;

however, flow was notably retarded through the screen pack

- Despite discrepancies of lab studies reported by different

organizations over the years the CDG technology has shown a

renewed interest at lab and field scale


Introduction:

CDG Development Review (Cont’d)

• The first CDG flood was implemented in 1985 in the Edsel

Minnelusa Unit, Crook County, WY

- The flood switched from the layered to the CDG process

- Results showed an incremental recovery of 11.5 % OOIP

• To date, over 70 CDG floods have been implemented in the

U.S. and abroad

T h e Sc i e n c e o f En h a n c e d O i l R e c o v e r y T h e Sc ie n c e o f En h a n c e d O i l R e c o v e r y

Summary of EOR &

CDG Projects in

Wyoming


Wyoming Tertiary Projects: 2008 Wyoming O&G Stats, The WOGCC

• To date, 39 CDG floods have been completed in Wyoming

~42% of polymer floods

are CDG floods


Evaluation of Chemical Flooding in the

Minnelusa Formation, PRB, WY*

• EORI publication evaluated the EUR of 32 chemical (mostly

polymer) and waterfloods

• The primary conclusions were:

- Chemical flooding improves recovery by an average of

9% OOIP compared to waterflooding

- Chemical flooding produces more oil sooner

- The sooner you start EOR the more oil you recover

*Thyne, G., Alvarado, V., Murrell, G., Evaluation of Chemical Flooding in the

Minnelusa Formation, Powder River Basin, Wyoming. Search and Discovery,

Article # 50239, February 26, 2010.


Minnelusa Production Analysis

Courtesy of EORI

CDG or CDG + polymer floods (PF’s) reported as PF only

ASP


CDG Experience in Wyoming

• Not all CDG projects in Wyoming (Mainly Minnelusa Fm.) were

reported as successful (SPE-27780):

• There are successful and highly profitable projects too (>20)

• In summary, CDG technology can fail as much as other EOR

methods. However, not all unsuccessful projects are published

or recognized

Unsuccessful Projects Marginal Economics

Swartz Draw, Campbell Co., 1987 Stewart Ranch, Campbell Co., 1985

Long Tree, Campbell Co., 1988 Pfieler Lease, Campbell Co., 1987

Bishop Ranch, Campbell Co., 1990 Spirit Field, Crook Co., 1993

Ottie Draw, Campbell Co., 1990

Wolf Draw, Crook Co., 1991


CDG Experience in Wyoming: N. Rainbow Ranch Unit (SPE-27773 Updates)

• Summary of reservoir and fluid properties (R71W – T49N)

Formation Minnelusa

Depth 9,500 ft

Porosity 19.7%

Water Saturation 20%

Temperature 202°F

Permeability Range 1 - 1,000 mD

Perm. Variation (DP) 0.9

Oil Gravity 26°API

Oil Viscosity 3.94 cP


CDG Experience in Wyoming (Cont’d): N. Rainbow Ranch Unit (SPE-27773 Updates)

Stage Injection

bbls Product* Pounds

Concentration

mg / l

1 81,000 Cationic

Polymer 22,000 775

2 46,000 Anionic

Polymer 22,500 1,400

3 198,000 Anionic Polymer

Al-Citrate

83,100

71,000

1,200

1,000

4 654,000 Anionic Polymer

Al-Citrate

68,700

76,000

300

330

• Summary of CDG treatment design:

* Polyacrylamide polymers



CDG Performance (Oil rate vs. time)

#6 Casing Collapse



900 MBO Incremental


CDG Experience in Wyoming (Cont’d): N. Rainbow Ranch Unit Summary Conclusions

• Approximately 12% PV was injected over the life of chemical

flood

• CDGs using high molecular weight polymer were

successfully injected into a non-fractured, high permeability

sandstone formation

• Total recovery to date of 49.4% OOIP

• Preliminary incremental recovery estimates were estimated

in 8.0% of OOIP (SPE-27773). Current analysis suggests an

incremental recovery of 15.7% OOIP

• Updated results estimate a development cost of $1 per

incremental barrel


Recent Advances in

CDG Lab &

Simulation Studies


• CDG lab studies shows large discrepancies and different

laboratory protocols

• Recent studies in Canada, Norway and Colombia reported:

− “CDG systems promote in-situ permeability reduction in

unconsolidated high-permeability porous media as opposed to only

the mobility control effect of polymer flooding” (CIPC 2009-045)

− “CDG propagates through water-wet Berea sandstone cores with

no chromatographic separation “ (SPE-129927)

− CDG injection in slim tubes showed PV reduction supported by

tracer injection before and after treatment (Castro, R. MSc.

Dissertation, UIS, Bucaramanga, Colombia, August 2011)

• Since 2009 Tiorco started comprehensive lab and simulation

studies as an effort to improve the understanding of CDG

CDG Technology:

Laboratory Study Updates


CDG Technology:

Laboratory Study Updates (Cont’d)

Castro R., August 2011

Before CDG After CDG


CDG (20:1) vs. Polymer Flooding:

1ft Slim Tube Tests (~ 3 Darcy)

3,0

206,8

70,9

110,0


CDG (20:1) vs. Polymer Flooding:

1ft Slim Tube Tests (~ 7 Darcy)

2,4

177,8

46

117,8


• CDG pilot project (4 injectors) was presented showing a

reasonably good history match using gel option

• CDG predictions are in agreement with current oil production in

the field

• CDGs and polymer flooding generated similar incremental oil.

However, CDGs required 40% less mass of polymer

• Injection well pressures and/or oil recoveries can’t be properly

match using skin factors

• Tracer breakthrough (BT) times before and after CDG injection

support changes in porous media (CDG delay tracer BT)

• CDG injection of 0.2 PV was possible in a thin (25 ft) and low

permeable (1-600 md) formation (8 cp crude oil)

CDG Technology: Simulation Updates (U.S. Pilot 2010-2011)


CDG Experiences

Elsewhere


• An important number of CDG field tests have been

documented in the literature

− CDG field (29) projects review (SPE 20234 & 27780)

− Adon Road (SPE-35352) and Lone Cedar (SPE-17539)

− Daqing Field, China (SPE-62610)

− Loma Alta Sur (SPE-113320) and El Tordillo (SPE-113334) Fields,

Argentina

− Dina Cretáceos, Colombia (SPE-139200)

• Despite the number of field projects, not much effort has been

dedicated to interpret/correlate lab. & field performance.

However, there are ongoing efforts to evaluate past and

current experiences

CDG Experiences Elsewhere:

Summary Review


• As of today, there are several ongoing projects in Argentina

(Confidential Client, 5 patterns), Colombia (Dina Field, 1

pattern) and the U.S. (4 projects, 1 to 4 patterns)

− Based on advanced screening studies (Alvarado & Manrique,

2010; SPE-139200) have identified Minnelusa reservoirs as

possible analogs of multiple Colombian reservoirs

− Bracken, Candy Draw Unit and Rule Fields are few of the

closer analogs to Dina Field in Colombia

− Screening study contributed to justify CDG evaluation and

field implementation based on field properties and project

economics

− Tiorco is also performing designs for projects scheduled 1Q and

2Q of 2012 in Canada, China and the U.S. including Wyoming

CDG Experiences Elsewhere:

Summary Review (Cont’d)


• Highly heterogeneous

reservoir (28 cp, T = 85°C)

• Tracer breakthrough times

(< 3 days 40 Acres)

• RF 25% (1ary + 2ary)

• Marcit gel treatments of

12,000 - 15,000 bbl

(Nov/05)

• 0.12 PV of CDG

(Jul/06 – May/07)

El Tordillo Field, Argentina: Polymer Gels + CDG (SPE-113334)


El Tordillo Field, Argentina:

Pilot Results and Current Plans

• Incremental oil of 50,000 m3 as of Dec. 2007

• As of April 2010 pilot still showed incremental oil


Loma Alta Sur, Argentina:

Inj. Profile Before & After CDG (SPE-113320)


Loma Alta Sur, Argentina:

Pilot Results


Closing Remarks


• CDG process is a variation of polymer flooding (PF)

• CDGs can generate similar incremental recovery factors as

PF using less mass of polymer (Economics!)

• Additional benefits of CDGs include:

• Generate higher RF and RRF than PF at the same (or

lower) polymer concentration

• Injectivity can be controlled without impacting water

viscosity, especially in viscous and low permeable

reservoirs

• CDGs has been successfully implemented in the Argentina,

China and the U.S (> 70 projects)

CDG Technology:

Closing Remarks


• YES, CDG technology is not well understood. However, are

all EOR technologies fully understood?

− If yes, why does there still exist risk aversion to implement EOR

projects even at oil prices > $80/bbl?

• Are CDG lab studies representative enough to explain field

performance? There is still lot work to be done

• Final messages:

− If project economics shows enough merits to evaluate an EOR

technology, do not wait to fully understand the technology and/or

wait to have a perfect model to start field implementation (99.9%

of the cases our interpretation will change with field data!)

− Manage Risk and Uncertainties are key for EOR

CDG Technology:

Closing Remarks (Cont’d)

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