Perpustakaan Digital ITB

The Alpha Field is a mature gas field operating without compression in a two-branch production network supplying the Beta export line and the Gamma processing facility. As reservoir pressure declines, several producing wells approach critical flowing pressure conditions, reducing well deliverability and increasing the risk of liquid loading while making it more difficult to satisfy the required gas allocation to both outlet branches. Consequently, production optimization must consider not only reservoir performance but also the hydraulic interaction between the reservoir, wells, and surface production network. This study develops an integrated production model by coupling reservoir, well, and surface network models calibrated to historical production data. The validated model is used to evaluate the effect of reducing the Gamma incoming separator pressure through sensitivity analysis. Production forecasts are performed for multiple operating scenarios, and the results are assessed based on cumulative gas production, recovery factor, gas allocation stability, and revenue using three gas-price scenarios. The results show that lowering the Gamma incoming separator pressure increases reservoir drawdown, improves well deliverability, and raises cumulative gas production by up to 11.1% and projected revenue up to 11.5% compared with the base case. However, pressure reduction also redistributes gas flow between the Gamma and Beta branches, requiring coordinated adjustment of the Beta operating pressure to maintain the target gas supply to Gamma. Among the evaluated scenarios, reducing the Gamma incoming separator pressure from 325 psig to 225 psig provides the most stable gas allocation while maximizing production and economic performance. The study demonstrates that separator pressure optimization in a two-branch integrated production network should simultaneously consider hydraulic interactions, production constraints, and economic performance rather than evaluating separator pressure reduction solely from production improvement.