Colloidal Dispersion Gels (CDG) and Their Application in Wyoming - - PowerPoint PPT Presentation

The Science of Enhanced Oil Recovery

The Science of Enhanced Oil Recovery

• E. Manrique & M. Lantz

Colloidal Dispersion Gels (CDG) and Their Application in Wyoming and Elsewhere

Jackson Hole, WY, September 12-13, 2011

The Science of Enhanced Oil Recovery

• 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

The Science of Enhanced Oil Recovery

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

The Science of Enhanced Oil Recovery

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

• f 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
• rganizations over the years the CDG technology has shown a

renewed interest at lab and field scale

The Science of Enhanced Oil Recovery

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

The Science of Enhanced Oil Recovery The Science of Enhanced Oil Recovery

Summary of EOR & CDG Projects in Wyoming

The Science of Enhanced Oil Recovery

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

The Science of Enhanced Oil Recovery

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.

The Science of Enhanced Oil Recovery

Minnelusa Production Analysis

Courtesy of EORI

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

ASP

The Science of Enhanced Oil Recovery

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
• r 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

The Science of Enhanced Oil Recovery

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

The Science of Enhanced Oil Recovery

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

The Science of Enhanced Oil Recovery

CDG Experience in Wyoming (Cont’d):

• N. Rainbow Ranch Unit (SPE-27773 Updates)

CDG Performance (Oil rate vs. time)

#6 Casing Collapse

The Science of Enhanced Oil Recovery

CDG Experience in Wyoming (Cont’d):

• N. Rainbow Ranch Unit (SPE-27773 Updates)

900 MBO Incremental

The Science of Enhanced Oil Recovery

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

The Science of Enhanced Oil Recovery The Science of Enhanced Oil Recovery

Recent Advances in CDG Lab & Simulation Studies

The Science of Enhanced Oil Recovery

• 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

The Science of Enhanced Oil Recovery

CDG Technology: Laboratory Study Updates (Cont’d)

Castro R., August 2011

Before CDG After CDG

The Science of Enhanced Oil Recovery

CDG (20:1) vs. Polymer Flooding: 1ft Slim Tube Tests (~ 3 Darcy)

3,0 206,8 70,9 110,0

The Science of Enhanced Oil Recovery

CDG (20:1) vs. Polymer Flooding: 1ft Slim Tube Tests (~ 7 Darcy)

2,4 177,8 46 117,8

The Science of Enhanced Oil Recovery

• 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)

The Science of Enhanced Oil Recovery The Science of Enhanced Oil Recovery

CDG Experiences Elsewhere

The Science of Enhanced Oil Recovery

• 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

The Science of Enhanced Oil Recovery

• 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)

The Science of Enhanced Oil Recovery

• 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)

The Science of Enhanced Oil Recovery

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

The Science of Enhanced Oil Recovery

Loma Alta Sur, Argentina:

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

The Science of Enhanced Oil Recovery

Loma Alta Sur, Argentina:

Pilot Results

The Science of Enhanced Oil Recovery The Science of Enhanced Oil Recovery

Closing Remarks

The Science of Enhanced Oil Recovery

• 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

The Science of Enhanced Oil Recovery

• 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%

• f the cases our interpretation will change with field data!)

− Manage Risk and Uncertainties are key for EOR

CDG Technology: Closing Remarks (Cont’d)