Perpustakaan Digital ITB

Many oil fields in Indonesia have entered the mature-field stage, characterized by declining reservoir pressure and increasing water production, making production optimization increasingly critical to meet national hydrocarbon targets. This paper presents a production optimization study conducted in cluster Y of Field X, an offshore production unit located in the Java Sea, consisting of 12 Electrical Submersible Pump (ESP)-lifted production wells connected through an integrated surface network comprising 5 manifolds, 2 gathering stations, and 1 flare gas system. Well performance models were constructed for all producing wells using the Inflow Performance Relationship (IPR) based on the Vogel correlation. Sensitivity analysis on tubing inner diameter was conducted to address uncertainties in actual tubing conditions, yielding a history-matched model with a coefficient of determination (R²) of 0.9986 against actual field production data. A quadrant mapping approach is introduced in this study, utilizing the ratio of actual production rate to Absolute Open Flow Potential (Q/AOFP) and ESP pump efficiency as evaluation parameters, to assess well production potential and pump performance conditions. This approach enables systematic identification of wells requiring further evaluation, prioritization of optimization candidates, and performance comparison before and after optimization. Integrated surface network simulation model was subsequently used as the basis for production network optimization. The optimization was performed using a production system simulation software, which internally employs a Mixed Integer Nonlinear Programming (MINLP) formulation solved via the BONMIN framework, with ESP operating frequency as the continuous variable and well operational status as the integer variable. The optimization was conducted subject to a maximum total ESP power consumption of 550 hp and a maximum field water handling capacity of 4,450 BPD. The optimization results demonstrate that total oil production in cluster Y of Field X increased by 26.56%, from 1,649 BOPD to 2,108 BOPD, while total water production simultaneously decreased by 10.0%, from 4,329 BPD to 3,936 BPD, without violating any established operational constraints and without requiring well intervention. These simultaneous improvements in oil and water production highlight the effectiveness of field-wide network optimization in redistributing ESP operating conditions across all wells within the integrated production system. Quadrant mapping further confirmed and quantified this improvement, demonstrating its capability to systematically evaluate well performance, identify wells requiring further attention, and capture the shift in operating conditions before and after optimization, with wells in the least favorable performance category reduced from six to two. These results demonstrate that the combination of quadrant mapping as a well performance evaluation tool and field-wide network optimization through integrated production system simulation constitutes an effective and operationally practical framework for production enhancement in mature offshore fields operating under power and water handling constraints.