Reaping Potential Reserves in Mature Channel Sand Field Using Boundary Mapping Technology

Abstract

BZ25–1 is the largest development field of CCLT (CNOOC CHINA LTD- TIANJIN) in Bohai bay. Its main deposition environment is shallow delta, fluvial channels combined with multiple post-diagenesis tectonic movements. After 10 years' production, the water-cut ratio had increased to 58%. Thus, production optimization becomes a major challenge for the operator. Supported by detailed seismic research and production data analysis, large potential hydrocarbon reserves are still recoverable. However, to tap these reserves, well trajectory has to be paced preciously and consistently in a suitable position in this mature field. After considerable data assessment and study in measurement feasibility, boundary mapping technology based on resistivity contrast and rotary steerable system were selected as the integrated solution. By employing this advanced technology, detailed reservoir profile is obtained and provides significant information for proactive geo-steering beneath the reservoir cap rock. With rotary steerable system, the trajectory is optimized to satisfy the reservoir's requirement for precise well path control, and substantially reduce construction risk in a complex environment. Total recovery factor has been improved 37% in this drilling campaign. Optimizing remote data transmission system, a multi-disciplinary team's real time execution delivered in best class results of a net-to-gross (NTG) increase to 94% with a reduction in water production for first time.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015