Abstract Some of the key challenges facing producing organizations are to increaserecovery from existing fields and to optimize the utilization and value ofexisting infrastructure. The Middle East is uniquely positioned to help supplyworld energy demand through efficient application of secondary and tertiaryrecovery techniques in super-giant carbonate reservoirs. Three long-lifecarbonate fields in the USA are offered as examples of the benefits achieved bya continuous process of data collection, studies, and systematic application ofavailable technologies. This continuous process has progressively increasedultimate recovery. The example fields will achieve a range of incrementalincreases in the recovery factor of between 8 and 20 percent originaloil-in-place (% OOIP) or up to 50% OOIP increase over conventional primaryrecovery. A systematic and integrated approach to reservoir management has beenemployed to understand the basic rock and fluid physics of each reservoir andthe key parameters that impact performance. The development plan for each ofthe example fields has then been implemented in a way that maximizes bothhydrocarbon recovery and value of the assets while utilizing best availabletechnologies.The Jay Field, in the southeastern United States is a deep, heterogeneous, carbonate that was discovered and put on production in the1970's. The field is geologically complex, including cemented zones associatedwith stylolites that restrict vertical flow. Using sophisticated3D-geostatistical models and advanced reservoir simulation, we were able tooptimize the performance of both a waterflood and a miscible nitrogen (N2)flood over the field life. As a result, we expect to achieve a recovery of morethan 60% OOIP. Currently, the field has produced over 50% OOIP.
The Salt Creek Field in West Texas is a carbonate that provides anexample of the benefits of successive implementation of infill drilling andimproved recovery processes to increase recovery. Acquired in the late 1970's, the field was the subject of two infill-drilling programs and development of aflank residual oil zone (ROZ). Studies were conducted to balance injection andwithdrawal and to better understand the complex stratigraphy. The field isexpected to achieve a recovery factor of greater than 60% OOIP using a carbondioxide (CO2) water-alternating-gas (WAG) process. Currently, the field hasproduced over 50% OOIP.
The Means Field in West Texas is a carbonate with low permeabilityand high viscosity oil and an underlying aquifer. An infill-drilling program, improved waterflood, and a CO2 WAG flood in a portion of the fieldsignificantly increased recovery. The field is expected to achieve a recoveryfactor of about 45% OOIP within the CO2 project area. Currently, thefield has produced over 30% OOIP.
Lessons learned are summarized and a process is recommended to address thechallenges of improving recovery from similar Middle Eastern carbonatefields.
Parameters Controlling Recovery ExxonMobil has established a large knowledge base of secondary and tertiaryproject experience at the laboratory, pilot-test, and field implementationstages. Projects include waterfloods, immiscible and miscible gas injection forsecondary oil recovery, tertiary WAG, foam-assisted WAG, and re-injection ofsour or acid gas for both oil recovery and sulfur/CO 2 disposal.