ABSTRACT
Background: The case study reservoir with a Static pressure of 3200 Psig, Temperature of 210 F a water cut of zero for initial study since it is a volumetric reservoir has a permeability of 50md and a drainage area of 500 acres, crude produced from the case study reservoir has a Solution GOR of 820 scf/STB, Oil gravity 34 API and a specific gas gravity of 0.833. As a volumetric reservoir pressure is expected to decline as production continues. To reduce the effect of pressure drawdown gas lift installations is considered in optimizing production from this reservoir.
Method: Gas lift would be designed for a single well producing from this field for both current reservoir conditions and future conditions Gas lift parameters that would be determined are Number of Valves, Gas lift Injection depth, injection pressure and Injection Rate and in doing so sensitivity analysis would be carried on the gas injection rate as pressure declines to see the best Injection rate that would optimize the well. Also Surface facility designs were not considered in this study.
Results: It was observed that three chokes at depths of 2832.58, 4738.27 and 6013.89 ft, Gas Injection pressure of 1400psig and an Injection rate of 1.112 MMscf/ day are required to obtain a production rate of 7000 STB/day at current reservoir conditions. But as reservoir conditions changed due to decline in reservoir pressure the gas injection rate that would optimize the field was 2.7MMscf/day given all other injection parameters are constant.
Conclusion: From the results gotten it was observed that when designing a gas lift system the future reservoir conditions should also be put into consideration and such needed adjustments put in place as there might be need for more gas injected, more injection pressure in the future such should be considered in designing the surface gas injection facility.
