Enhanced Oil Recovery by Co₂ Injection, Powder River and Washakie Basins, Wy

Isaacs, Angela ¹; Mordick, Briana ¹; Williams, Anthony ^1
1 Anadarko Petroleum Corporation, Denver, CO.

Enhanced oil recovery (EOR) techniques facilitate the production of otherwise unrecoverable reserves from mature oil fields. In the case of CO₂-injection, EOR provides the additional environmental benefit of long-term geologic sequestration of a significant greenhouse gas. Anadarko has extensive experience in EOR projects throughout the US and abroad. Two major fields in Wyoming are currently undergoing enhanced oil recovery by CO₂ injection; Salt Creek and Monell.

The Salt Creek field, located in Natrona County, WY, was discovered in the late 1800s and has been continually producing oil since 1908. Salt Creek has an OOIP of 1,680 MMBO and cumulative production of 700 MMBO, making it the largest oil field in Wyoming. Anadarko acquired Salt Creek in 2002, began CO₂ injection in 2004, and is currently producing approximately 6500 BOPD while injecting 320 MMCFD of CO₂. Development is occurring in phases, with 5 of 18 phases currently under CO₂ flood. Full-field development is scheduled to be completed by 2023. Estimated ultimate recovery from the CO₂ flood is an additional 10-15% OOIP with planned sequestration of approximately 800 BCF of CO₂. Anadarko is applying cutting-edge technology to the implementation and management of the flood, including reservoir modeling and simulation and an industry-leading 4D seismic survey.

The Monell Unit of the Patrick Draw Field, located in Sweetwater County, WY, was discovered in 1959. Monell has an OOIP of 118 MMBO and cumulative production of 40 MMBO. The Unit was producing less then 15 BOPD prior to the onset of CO₂ injection in 2003. Current production is 3400 BOPD while injecting 45 MMCFD of CO₂. Development is occurring in phases, with 2 of 4 phases presently under CO₂ flood. The planned sequestration at full-field development is approximately 85 BCF of CO₂. Most recently, 9-spot patterns were introduced to aid in understanding of the development potential. Unlike Salt Creek, Monell is not amenable to WAG, and injects 100% CO₂. This allows the use of a state-of-the-art, fully automated operation system.

Upon completion, combined CO₂ sequestration at Salt Creek and Monell will be approximately equivalent to the annual greenhouse gas emissions from 9 million passenger vehicles. An extensive inventory of potential CO₂-injection EOR projects exists in the Rocky Mountain region and throughout the US. Currently one of the most significant challenges regarding the future development of these projects is CO₂ supply.

AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009