A High Success Rate Acid Stimulation Campaign—A Case History

Abstract

Abstract A successful acid stimulation campaign was conducted in 2004 in Brunei Shell Petroleum (BSP). This paper discusses what have been done differently, best practices, and learning. What is different in this campaign from previous ones? Detailed design Detailed well-by-well review for first round candidate selection. Fundamental data collection (well data, pressure, formation fluids - water and oil, mineralogy data and lab tests…). Data management system allowing for quick access to well production history data. A design tool (Stim2001) for detailed candidate selection, damage diagnosis, fluid system selection, and job design. QA/QC and compatibility tests aiming to obtain high success rate. In Brunei Shell, a self-raising rig (BIMA) with a coil-tubing unit on board is used to overcome the limitations due to weather. A combined pumping procedure (coiled tubing and bull-heading) was implemented to best-fit individual well condition. Close cooperation among different parties (Well services, Subsurface technology teams, Operation services, and Service providers, etc.) 6000 bpdoe of initial gain was achieved by this campaign in Brunei with high success rate (no failure on single well was recorded). Confidence level of acid stimulation in Shell Asia Pacific region has been elevated through this stimulation campaign. Lessons learnt and best practices established will be passed to future campaigns. We would like share our belief that acidization is still a good means for stimulating well productivity, but it has to be carried our properly.