Abstract: Post Steamflood Reservoir Management Using a Full-Scale Three-Dimensional Deterministic Thermal Reservoir Simulation Model, Wilmington Field, California

MONDRAGON III, JULIUS, University of Southern California, Los Angeles, CA; ZHENGMING YANG, University of Southern California, Los Angeles, CA; IRAJ ERSHAGHI, U. of Southern California; PHILIP HARA, Tidelands Oil Production Co., Long Beach, CA; SCOTT BAILEY, Dept of Oil Properties, City of Long Beach, Long Beach, CA; ROY KOERNER, Dept of Oil Properties, City of Long Beach, Long Beach, CA

This paper describes a simulation based reservoir management approach to convert a steamflood to a waterflood in a stress sensitive reservoir. Maintaining reservoir pressure during the conversion process and the follow-up operations is too complex to perform intuitively. Reservoir pressures are affected by the mixing and movement of the hot and cold fluids in the reservoir, the continuous heat losses to the overburden and underburden formations, the steam chest collapse and expansion in the structurally updip areas, and the movement and production of hot fluids throughout the steamflood area. This paper includes a case history of successfully using a full-scale three-dimensional deterministic thermal reservoir simulation model to convert a mature steamflood to a waterflood in the Fault Block II-A Tar Zone in the Wilmington Field, California.

The successful match of a complex production history allowed the development of a real time simulation tool for strategic planning of field monitoring and operation. The objectives achieved included determination of: optimal number and location of injection wells to receive 135 ° F water; proper injection rates to fill up the reservoir and to collapse the steam chest in a minimal time; required reservoir pressure to prevent surface subsidence; critical oil production rates preventing reestablishment of the steam chest; and minimized capital cost and operational expenses for the conversion process. The simulator is conditioned to receive updates of information related to injection, production, and pressure data on a monthly basis and provides comparison of actual with projected performance. The real time response capability of the simulation approach has made it an indispensable tool for day to day decisions and reservoir management purposes.

This study is part of the U. S. Department of Energy Class III mid-term Project Cooperative Agreement No. DE-FC22-95BC14939 "Increasing Heavy Oil Reserve in the Wilmington Oil Field through Advanced Reservoir Characterization and Thermal Production Technologies".

AAPG Search and Discovery Article #90911©2000 AAPG Pacific Section and Western Region Society of Petroleum Engineers, Long Beach, California