Michael Raines, Kinder Morgan CO, Co. LP
The 2.8 Billion Barrel (Original Oil in Place) SACROC Unit is located in Scurry County, Texas and produces from the Pennsylvanian-aged Cisco and Canyon Formations of the Kelly-Snyder and Diamond M Fields. This Unit has had a colorful history, with discovery shortly after World War 11, nearly half a century of waterflooding, three decades of tertiary development, and a wide variety of operators and philosophies. Since the time of SACROC's early CO, efforts, local experience and industry practices have contributed greatly to our knowledge of CO, flooding in general. Today, Kinder Morgan CO, Co., L.P. (KMCO,) is CO, flooding an area in the central portion of the Unit (using new techniques and philosophies) with great success. Unit production is now at a nineyear high, with average monthly production exceeding 13,000 BOPD. Tertiary recovery efforts are very expensive and require a great deal of reservoir understanding to reduce risk and increase efficiency. So, KMCO, has initiated a dual-pronged approach to the continued development of SACROC Unit, with flooding efforts currently focused on "less risky" areas, and with more intense geologic study focused on understanding the more complex, higher risk, and greater potential areas. However, even in the low risk areas this reservoir is extremely complex and data is sometimes scarce, misleading, of low quality, or ambiguous. Relatively few modern logs exist, and unique situations can cause confusion about log responses. Correlations are difficult in certain areas due to complex geometries associated with mound buildups, erosional contacts, and local depositional geometry. Because the reservoir's internal architecture is so complex, strange fluid flow responses sometimes occur in areas that appear rather simple at first glance. That said, the Unit can still be divided into northern, central, and south-western regions for general comparisons. A thick, north-south trending platform, with karst features that increase in intensity to the north and higher in the section, dominates the northern area. The central region is a broad, gently arching plain broken by steep-sided pinnacles, gentler mounds, intermittent sinuous lows, and localized depressions. The southwestern area is the most structurally complex region of the Unit, with a series of faults and channels that contribute to small, isolated compartments. Success at SACROC can be credited to the geology and hydrodynamics of the reservoir, the technical feasiblity of tertiary recovery with CO,, and the efforts of a multi-disciplinary team providing input from field, reservoir, and corporate levels.