During the production of gas condensate reservoirs which have underlying aquifers present, large areas of the reservoir can be invaded by water during pressure reduction, resulting in the entrapment of large quantities of hydrocarbons. In order to simulate this process in the laboratory, experiments were conducted using gas and condensate saturated cores which were initially flooded with water to simulate the entrapment of hydrocarbons. Pressure reduction of the cores was then initiated in order to allow the hydrocarbons to expand and reach a critical hydrocarbon saturation at which hydrocarbons remobilised.

It was found that the average critical hydrocarbon saturation required for remobilisation of hydrocarbons was approximately 0.56, which was about 0.12 higher than the initial hydrocarbon saturation. Pressure reduction was initiated at different stages in the phase behaviour of the gas condensate fluid in the cores. This appeared to have only a minor effect on the hydrocarbon expansion required for remobilisation when the initial hydrocarbon saturations were similar. The results highlighted significant differences between the hydrocarbon expansion required for remobilisation, the fluid production profiles after remobilisation, and the effect of pressure reduction rate on remobilisation, for the gas condensate compared to a single phase gas.

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