Successful Casing Architecture Optimization as Solution for Massive Drilling in Development of Low Quality Reservoir Project B-Oilfield with Marginal Economical Issue

Development of oil fields in the company's operating area mainly focuses on High Quality Reservoir (HQR). In general, most of the fields in the company's operating areas are considered mature. To accelerate national oil production, SKK Migas, as a special task force for Indonesian upstream oil and gas activities, requested all oil company in Indonesia, to seek opportunities to develop Low Quality Reservoir (LQR). B-Oilfield has several reservoirs, but not all of those are hydrocarbon-bearing reservoirs. In B-Oilfield, currently oil is produced from T-Reservoir, D-Reservoir and B-Reservoir. P-Reservoir assumed containing gas, T-Reservoir is categorized as low-quality reservoir, while D-Reservoir and B-Reservoir area categorized as high-quality reservoir. D-reservoir has loss circulation tendency. Figure 1 shows typical reservoirs in B-Oilfield. The LQR Development Project in B-Oilfield is a multiple year's project to drill 219 new wells. Previously, LQR wells in B-Oilfield were designed with 3 casing architecture: surface casing to protect water aquifer, intermediate casing to isolate potential gas in P-Reservoir and production casing to allow production from T-Reservoir. As mentioned earlier, this casing architecture was chosen due to the assumption that P-Reservoir in entirety of B-Oilfield containing gas. Figure-2 shows the 3-casing architecture which was previously used in development of LQR wells in B-Oilfield.