Parametric Study of Condensate Buildup in a Naturally Fractured Gas Condensate Reservoir

Abstract

Abstract The main difficulty usually encountered in gas-condensate reservoirs is the loss of valuable condensed liquid in the reservoir due to capillary forces, a phenomenon called condensate blockage. The presence of condensates when coupled with the complexity of fluid flow in fractured reservoirs can increasingly obscure the expected performance of such reservoirs. A thorough understanding of the factors leading to condensate buildup in fractured reservoirs is crucial for deciding a proper strategy to exploit such reservoirs. In this paper, a compositional model is used to predict and physically justify the single-well performance of a naturally fractured gas-condensate reservoir having different reservoir properties and production schemes. The current study reveals the important role of capillary pressure in trapping condensates, especially in highly fractured reservoirs where the effect of gravity drainage is minimized. Higher matrix block sizes can reduce the amount of trapped liquid. However, high critical condensate saturation can dampen the effect to some extent. Pore size uniformity is another important factor that causes less condensate buildup due to less capillary pressure. Higher production rates result in earlier condensate dropout peak. The peak is lower for higher rates, a phenomenon attributed to velocity stripping. Furthermore, the effect of gas and liquid diffusion is the most crucial in tighter matrices and can significantly reduce the trapped condensates.