Potential to increase condensate oil production by huff-n-puff gas injection in a shale condensate reservoir

•Provides a methodology to design and optimize huff-n-puff gas injection in shale gas condensate reservoirs.•Reveals a long huff-n-puff time for a typical shale gas condensate reservoir.•Reveals complex effects of injected gas composition on enhancing shale gas condensate production.

This paper presents a huff-n-puff gas injection method to increase condensate production in an Eagle Ford gas condensate reservoir using a simulation approach. The simulation study suggests that the huff time and puff time should be the same. Because of higher compressibility of a gas condensate fluid, either huff or puff time required will be longer than that for a shale oil reservoir. For the studied reservoir, an optimum huff or puff time is about 600 days. However, a shorter time of 300 days is preferable for recouping the cost for facilities. To improve the overall liquid condensate recovery performance, during the last half of the development period, the huff-n-puff may be changed to pressure depletion so that the energy injected earlier can be fully utilized. Other effects such as those of initial water saturation, injection pressure, and gas composition, are also investigated in this paper. The methodology presented in this paper is applicable to other gas condensate reservoirs, and some of results or conclusions may be typical of gas condensate reservoirs.