Abstract:
Demand of natural gas is always higher than the supply in Bangladesh. Correct estimation of
reserve is important for the development of the gas fields, design of production facilities and
preparation of the gas contracts. Narshingdi is one of the gas fields of Bangladesh Gas Field
Company Limited (BGFCL). This field was discovered by Petrobangla in 1990. The
objective of this study was to estimate the Gas Initially In Place (GIIP), remaining reserve,
reservoir boundary, and various petrophysical data of Narshingdi gas field.
There are two gas sands, Upper Gas Sand (UGS) and Lower Gas Sand (LGS) in this field.
Gas production started in 1996 and presently the two producing wells (NAR-1 and NAR-2)
are producing gas from LGS at a rate of 17 and 11 MMSCFD respectively. Seventeen years
of production data (1996 to 2013) have been analyzed to perform material balance and
advanced decline curve analysis. Monte Carlo simulation approach was also performed to
estimate proved, probable and possible reserve. Reservoir simulation using ECLIPSE 100
black oil simulator was performed for the purpose of history matching and production
forecast. Different forecast scenarios were designed to investigate the effect of additional
vertical well and gas compression on recovery.
The regular pressure survey of the field was not conducted and therefore Flowing Gas
Material Balance an alternative to conventional material balance was performed. In the
absence of pressure transient test (e.g., buildup, drawdown) data, advanced decline curve
analysis was performed to calculate the reservoir potentiality (permeability, skin), reservoir
area, GIIP and the ultimate recovery of the field.
This study shows that the reservoir is depletion type and the pressure decline is significant.
Adding more well in the lower gas sand will not be beneficial.
