Investigation of waterflooding and gas cycling for developing a gas-condensate reservoir

This paper presents the results of a full field compositional reservoir simulation study that compares the application of waterflooding and gas injection to a rich gas-condensate reservoir. Fluid (water or gas) injection is used to maintain the reservoir pressure above the dew point pressure and prevent condensate dropout in the reservoir. The simulation study shows that water injection is a viable option in producing gas-condensate reservoirs. The study shows that both water injection and gas injection result in higher recovery factors than normal depletion. Although gas injection showed higher condensate recovery factors, it may not be economical due to the required large initial investment, higher operating costs, and delay of gas sales. For the water injection to be effective, the reservoir should not be flooded completely with water. Rather, the reservoir should be blown-down before water invades the producing wells. Factors that affect the recovery of gas condensate reservoirs under water injection are highlighted. These factors include time to blow-down and imbibition relative permeability curves. Sensitivity analysis results are presented for these factors. Water injection has a major advantage over gas injection. In water injection produced gas can be immediately sold and compression cost is saved.

Investigation of waterflooding and gas cycling for developing a gas-condensate reservoir Conference Paper