Results of an Optimization Study on a Major Gas Field Complex

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc. Abstract This paper describes the results of recent optimization study of the Sheridan-Provident City gas field complex. A total of 34 reservoirs and 132 wells were studied in order to develop a plan which would optimize the recovery of the remaining gas-in-place. Production was initiated from these fields in Production was initiated from these fields in the middle 1940's, and they are presently about 75 percent depleted. Sheridan and Provident City are currently characterized Provident City are currently characterized by low pressure reservoirs and complex gathering systems. The gathering systems include:a high pressure, branched flow-line network;a low pressure flowline network with multiple loops;remote field compressors; andlarge central compressor stations. The problem involved modeling the performance of the reservoirs, wells, gathering systems and compressors in order to predict the field response to several predict the field response to several alternative plans of operation. The study was carried out by use of a digital computer program which can simulate the conditions existing during production of one or more gas reservoirs connected through a common surface gathering system. The program is capable of simulating both pure program is capable of simulating both pure depletion drive reservoirs and reservoirs having some degree of pressure support either from the expansion of rock and connote water, or from the influx of water from a communicating aquifer, or both. The surface gathering system can be looped and/or branched. Compressors can be simulated at any point in the gathering system and can be added or removed at any preset time. Two-phase flow is modeled in the gathering system and the production tubing, while semisteady state, single-phase flow is modeled in the reservoirs. This paper demonstrates that, even in the case of complex, mature fields, the use of sophisticated engineering techniques can increase the remaining recoverable gas reserves. PURPOSE AND SCOPE PURPOSE AND SCOPE The primary objective of this study was to formulate a plan which would optimize the recovery of the remaining Sheridan and Provident City gas reserves. Provident City gas reserves.