The Impact of Fickian Flow on Condensate Blocking, and Treatments for Both Low and High Permeability Cases

The study of depletion performance of gas condensate reservoirs has gained wide interest in petroleum industry during the last few decades and poses a challenge for the reservoir modeller. Upon depletion, falling the reservoir pressure below the dew-point of hydrocarbon mixture results in liquid condensation at reservoir conditions. This liquid may be temporarily or permanently trapped in the reservoir causing severe reductions in gas production rates and the permanent loss of a large portion of the volatile and valuable condensates. This becomes highly noticeable for the case of tight reservoirs (less than 10 md). Hence, it is critical to answer this question whether this trapped hydrocarbon has been irreversibly lost or not. It is believed that the interplay of Darcian-type flow and Fickian type flow (multi-mechanistic flow) is the key to answering this question. Therefore as the first goal of this study, by utilizing a compositional simulator (ECLIPSE 300) and modelling a synthetic reservoir with the fluid of one of the Iranian gas-condensate reservoirs; we try to assess the role of multi-mechanistic flow on the condensate appearance for the permeable (50 md) and tight (5 md) reservoirs. On the other hand, since gas injection/cycling is a main recovery process for preventing loss of valuable condensates, the methodological plan of this study is to do a sensitivity analysis on various gas injection/cycling scenarios in the reservoir at pressures below the dew point (maximum condensate appearance).