Reservoir simulation study of Fenchuganj gas field

Abstract

BAPEX operated Fenchuganj Gas Field, 40 kilometer south of Sylhet in Bangladesh, lies in the south central part of Surma basin. A second well FG-2 was spud on January 1985 after the first exploratory well drilled in 1960 was abandoned as dry hole. Three gas sands (Upper, Middle & Lower) were tested and completed the well at upper gas sand in 1988. Gas production from the well started on May 2004. Next a development well, FG-3 was drilled by BAPEX in 2004 and gas production started from January 2005. Gas production from upper gas sand of FG-2 was suspended after extracting 24 BSCF gas due to excessive sand and water production. Later the well was re-completed at lower zone and due to the same reason production rate was lowered. Therefore, future field development plans as well as diagnosis the reason of water break through of the well needs to be investigated.

Despite of volumetric analysis, under the project RMP-2 of Petrobangla in 2009, RPS Energy prepared dynamic reservoir simulation model of Fenchuganj Gas Field. In this current study, the geological model was revised by correlating with seismic and log data and imporated in a commercial 3D black oil reservoir simulator ECLIPSETM 100 to construct a dynamic reservoir simulation model. Later the dynamic simulation model was validated by using historical pressure and production rate data in history matching phase. Finally, the history match model was run for five different forecast cases to find out a better field development plan.

Forecast Case 5 of the current study yield 81.75% gas recovery out of 386.05 BSCF estimated GIIP after 25 years of prediction period by drilling additional three wells as well as workover of the existing wells. Aquifer support is identified in the upper gas sand during history matching as well as water break through in FG-2 has been investigated.