APPLICATION OF COLE PLOT TO BETTER ESTIMATE RESERVES IN A COMPLEX, MULTI LAYERED, WATER DRIVE GAS RESERVOIR (SISINUBI, INDONESIA)

摘要

Sisi Nubi is a gas field within the Mahakam PSC operated by Total E&P Indonesie. The field is compartmentalized by a number of faults, which subdivide the field into seven main panels. Reservoirs in Western panel are generally supported by a very active aquifer, while the Central panel generally has depletion drive mechanism. Properly quantifying aquifer strength is one of the main challenges to accurately determine reserves. A gas reservoir with transient aquifer support can plot as a near straight line on a P/Z plot, masking the existence of an active aquifer, and causing significant overestimation in gas reserves. Cole Plot is useful to distinguish aquifer support effect in CGIP estimation by including water entry effect in the material balance.