Formation damage through asphaltene precipitation resulting from CO2 gas injection in Iranian carbonate reservoirs

Although carbon dioxide (CO2) injection is one of the most common enhanced-oil recovery methods that is widely used in many reservoirs, it may change the reservoir-fluid properties and cause problems such as asphaltene precipitation that will result in reduction of injectivity and productivity of oil wells and plugging of wellbores and production facilities. This paper describes the effect of a miscible CO2 flood on asphaltene precipitation in the Bangestan reservoir of the Kupal field in southwest Iran. The amount of asphaltene precipitation in the mixture of oil and CO2 gas was measured by means of a PVT (pressure/volume/temperature) test, and the mechanism of precipitation under reservoir conditions was obtained by a high-pressure coreflood test. Then, the experimental results were compared with those obtained from available asphaltene-precipitation models.