Abstract

The purpose of this study was to investigate the effect of production rates on the ultimate recovery in a gas reservoir with a strong water drive mechanism. The investigation utilized a two-phase and two-dimensional mathematical model.

The hypothetical reservoir is a dipping system, 12, 380 ft long, 1320 ft wide, 120 ft thick having a porosity of 15%, 13% connate water saturation, and a permeability of 20 md.

This reservoir with an initial pressure of 7115 psia at the orgiginal gas-water contact at-10.100 ft contains 53.8 BSCF of nonassociated gas originally in place.

Results indicate that ultimate recovery and rate of gas recovery are increased by producing the field at high rates. With a variety of production rates between. 10 and 10 times gravity reference rate, the ultimate gas recovery ranges from 66.6% to 91.8% of the original gas in place (OGIP), with economic life the field of 444 and 23 years, respectively.

The rate sensitivity of this reservoir is also dependent on the equilibrium gas saturation shown by relative permeability and capillary pressure data. Consequently, reliable inhibition laboratory test data are required.

The effects of relative permeability, water and gas, and capillary pressure on the ultimate gas recovery were also investigated.