Abstract

Gas utilization is one aspect of Indonesia's energy diversification policy to mitigate the anticipated decline in crude oil production. Pertamina as an oil and gas producer has made many efforts to improve the security of gas supply through a gas management approach. Reservoir management is a continous effort to improve and to provide added value to the reservoir by maximizing recovery, optimizing the production, minimizing the capital and operating cost, and making an integrated work program to develop the reservoir from discovery to abandonment.

The remaining reserves of Pertamina UEP Sumbagut Gas Reservoir are around 493.1 BSCF. Currently, the committed gas demand of PLN and PGN is 42.8 MMSCFD. In compliance with population and industrial growth, the forecasted gas demand is up to 200.6 MMSCFD in the beginning of Fiscal Year 1995/1996.

This paper explains the gas reservoir management concept to meet the demand of 200.6 MMSCFD. The analysis is based on gas deliverability and material balance calculations, to provide Absolute Open Flow Potential (AOFP), Production Forecast of Gas Deliverability, and Future Pressure Prediction.

The plan of Development for gas structure in Pertamina UEP Sumbagut consists of 26 new wells, 213 workovers, and 68 well reopenings, compressor reallocation for SP-I and SP-IX, purchasing of compressors (1 of 10 MMSCFD capacity, and 42 of 1.5 MMSCFD capacity), installing 216 km flowline, and 1 Block Station. Existing transmission facilities, and a capacity-increasing project, which is in progress, will be sufficient to meet the demand. Further work is needed to develop the potential reserves and discover exploration gas resources to get additional reserves.

According to the existing gas proven reserves and the demand, Pertamina UEP Sumbagut is able to comply with the gas demand for 5 years. The implementation of this plan will need an investment of U$.104,395,446 and the gas production cost will be US$.1.63/MSCF. The economic analysis indicates the Payout Time is 4.29 years, IRR 21.80% and PI 2.14.