Technical Initiatives and Cost-Effectiveness to Optimize The Drilling Project of The Jambaran Sour Gas Field Development

The Jambaran structure is a gas field located in East Java, Indonesia. From 2019-2021 the development project has been carried out by drilling five new wells and re-entry one well with additional activities of temporary plug and abandonment (P&A) of one exploration well. This paper discusses several technology initiatives and cost-effectiveness to optimize the drilling project in the Jambaran-Tiung Biru (JTB) Field. The design of the well shall meet the composition of 34% CO2 and 1% H2S in the reservoir. According to this sour gas condition and to meet the raw gas production of 315 MMSCFD, the project requires a specific design of the long-lead item. These had longer time delivery compared to the usual carbon steel. The Operator and SKK Migas took several initiatives for optimization. The drilling project was divided into two methods: drilling with a rig and completion with a rigless. The rig operation was optimized by applying a batch drilling sequence to meet material delivery time. Optimization also came from the drilling time on each hole section, mud utilization, casing, and cementing programs compared with the actual activities. Took corrective actions and learned about drilling problems. The completion job consists of perforation work 800 feet long in the reservoir target, well cleanup work, and production testing safe and effective. The well costs evaluated were based on the authorization for expenditure (AFE) compared with the actual cost estimate. The cost components that were evaluated include cost-per-foot and cost-per-day. The drilling project was completed 56 days earlier than planned. A Non-Productive Time (NPT) in an average of 3% and the results of the well test show that the production forecast is still as per plan. The estimated actual cost is 15% lower than the plan.