Optimizing Drilling Strategies in a Tectonic Belt, Pagerungan Field, North of Bali

摘要

Initial development drilling programs in the Pagerungan Gas Field were plagued by severe hole problems caused by tectonic stresses and dispersive formations, shallow gas events and logging problems. An optimization study was conducted using a database generated from 14 wells drilled over the past ten years. The results of this study showed that significant improvements in drilling performance could be achieved. A technique using wellbore stability days as an index was used to account for time-dependent effects of water-base mud systems on dispersive formations. This technique enabled an empirical refinement of a static-elastic wellbore stress model. Additionally, the use of a synthetic-base mud system eliminated the time-dependent effects allowing lower mud densities, casing string reductions, and dramatic increases in rates of penetration. A "batch" drilling/completion schedule accelerated the learning curve effect and optimized the program's logistical efficiency. By implementing the recommendations of the optimization study, improvements as high as 30