Review and Analysis of Zonal Isolation Effectiveness in Carbonate Reservoirs Using Multi-Stage Stimulation Systems

摘要

It is common practice to complete long carbonate intervals with multi-stage stimulation treatments especially in horizontal wells. Each zone tends to be mechanically isolated using cement or openhole packers and then acid stimulated. Zonal isolation effectiveness is judged on the basis of job pressure response or post-job production logging. The recent introduction of intelligent well systems (IWS) with zone specific pressure and temperature gauges allows more effective review of zonal isolation during stimulation. This paper reviews zonal isolation results from a series of high-rate acid jobs conducted in wells equipped with zone-specific pressure and temperature gauges. 21 acid stimulation jobs from 13 different wells are reviewed to investigate the effectiveness of zonal isolation during and after treatment. Well examples presented in this paper cover several different completion types: cemented and un-cemented; intelligent well system, plug-and-perf completion and ball-activated sliding sleeve completion. The analysis revealed several different pressure and/or flow communication patterns. Field examples and analysis results presented in this work will help engineers design and optimize cemented and un-cemented wells requiring multi-stage stimulation in carbonate fields.