Mahakam Success Story in Drilling and Wireline Logging by Utilization of Engineered Water Based Mud in High Reactive Clay Formation

Abstract

In Tunu, Tambora and Handil field of Mahakam area, the production section layer iscategorized into two types, which are shallow zone and main zone. Both zones are having highly reactiveclay, proven by XRD test, which is one of the challenges in drilling operation. It has been a best practicefor many years in Mahakam area to drill the reservoir section with Synthetic Base Mud (SBM) toencounter the reactive clay formation. The SBM system leads to the other technical requirement such asenvironmental policy, in its practice require a highly cost of waste treatment to be in compliant with theregulation. In the challenge of the SBM restriction, the Water Base Mud (WBM) system is expectedly to be the answer. The WBM might not perfectly equal to the SBM in term of fluid performance. However, with theaccurate engineering design, we can have the optimum WBM designed in line with operational needswhile promoting efficiencies. The project has been conducted to replace the SBM for drilling bothshallow and main zone wells, started with the study of the cutting from each zones, and the mapping ofdrilling fluid formulation which is technically and financially reasonable. There are 3 types of WBMsystem used in the project, for shallow zone the WBM system are KCl Polymer and Polyamine system. While for main zone, due to the high temperature environment, the HT-Polyamine system was utilized. The engineered solution has been successfully implemented in both shallow and main zone.Especially in shallow well, total of 35 wells have been drilled with WBM system, and cost effective isproven especially in batch wells drilling operation. While in Main zone, the HT-Polyamine WBM systemis had shown its capability for drilling reservoir, and the cost reduction is proven to plunge down to 18%compared to SBM system. Those cost reductions will be more when including the elimination of SBMwaste management cost. This success is also one of key answer to the more stringent policy inenvironment in the future, specifically in the zero cutting discharge regulation. Replacement of SBM withWBM. Successfully Drilling and Wireline Logging with Water Base Mud in high reactive clay formation.