PRODUCTION OPTIMIZATION IN SUBANG GAS FIELD USING RESERVOIR SIMULATION

摘要

Subang field is a dry gas reservoir with combination of drive mechanism, depletion and water drive. Initial gas in place is 970.3 BSCF with CO_2 content of 21.53 %. Until 30 April 2004, cumulative gas production is 35.0 BSCF or ± 3.6 % from initial gas in place with flow rate 114 MMSCFD from 13 wells those started producing in February 2002. In order to fulfill gas requirement of 140 MMSCFD in 8 - 10 years from Subang field, production optimization through reservoir simulation study is done by using Petroleum Workbench simulator. The Subang field simulation modeling is using regular grid corner point, type with 70 x 70 x 6 dimension with 118 m x 119 m size for each cell. History matching process is done using saturation matching method by adjusting the gas and water relative permeability curve (krg and krw) parameters. There are nine scenarios run until 31 December 2024, with variation of wells stimulation, additional of perforation interval and additional of new wells with production flow rate controlled at 150, 100, and 80 MMSCFD. All those scenarios . were run with minimum bottom hole pressure at 345 psi, and minimum field flow rate at 15 MMSCFD. From those simulation result and economic analysis show that the most effective scenario is third scenario which has the biggest recovery factor of 87.25 %, able to produce up to 150 MMSCFD for 7 years 4 months, and has the most profitable economic indicators with for each gas price of US $ 1.5, 2, 2.5 / MMBTU, this scenario has NPV US $ 10,8 MM, US $ 63,4 MM, US $ 113,4 M, ROR 14 %, 22 %, 28 %, PIR 1.9, 3.4, 4.9, and POT for 6.2 years, 4.5 years, 3.8 years respectively.