A Case Study of SACROC CO2 Flooding in Marginal Pay Regions: Improving Asset Performance

Abstract Since the beginning of injection in 1972, carbon dioxide has been utilized at the SACROC Unit of the Kelly-Snyder Field to improve and enhance oil recovery. As one of the first fields in the world to attempt this technique, SACROC provides a unique opportunity to study, learn from, and improve upon the development of this technology. Between initial gas injection and the year 2000, approximately 1 TCF of CO2 had been injected into the Canyon Reef reservoir. While multiple pilot programs from this time period reported incremental response following CO2 injection, many of these volumes are now attributed to residual waterflood affects as many of these projects were not truly miscible CO2 floods. Since that time, advances in technology, improvements in reservoir knowledge, and increases in scale have expanded the boundaries of economically viable enhanced oil recovery. As a result, projects that were once considered marginal in reservoir quality and redevelopment potential are now exhibiting improved recovery responses across the field. Since taking over as operator at SACROC in 2000, Kinder Morgan has redeveloped more than 25 major project areas including more than 600 patterns within the unit. Under Kinder Morgan operations, cumulative CO2 injection has surpassed 7 TCF yielding a cumulative enhanced oil recovery of over 180 million barrels. This case study will review the history of enhanced oil recovery at SACROC, discuss changes in theory over time, and provide a forward look at what remains for this field. This analysis will focus on the first CO2 injection pilot programs, dimensionless oil and CO2 recovery performance and their impact on forecasting, and inclusion of the transition zone and other marginal pay areas in redevelopment. Additionally, this study will highlight the major operational issues encountered over time and the associated improvements that have contributed to enhanced oil recovery. These advancements include conformance improvements, upgraded field surveillance, and proper management of the overall injection- production system. In conclusion, the case will review the Hawaii and East Flank CO2 Flood Expansions: two recently developed marginal pay projects undergoing miscible CO2 flooding at SACROC. Successful redevelopment of these marginal pay projects is allowing for expansion to areas of the field once considered marginal in quality and accordingly uneconomic.