Asphaltene Precipitation Study during Natural Depletion at Reservoir Conditions

This study concerns with experimental investigations of asphaltene precipitation at reservoir conditions of a crude sample from an Iranian oilreservoir during pressure depletion. High pressure high temperature setup and filtration method was used to quantify amount of precipitated asphaltene at different pressures. In addition the effect of temperature on asphaltene precipitation during pressure depletion has also been examined. The experimental results have been used to develop the asphaltene precipitation model with the application of commercial software as well. The results of this study confirm that asphaltene precipitation increases when temperature decreases. After the pressure onset, asphaltene precipitation increases with reduction of pressure and reaches to a maximum near the bubblepoint. Furthermore reduction in pressure leads to asphaltene redissolusion due to light gas liberation. Also it is revealed that denser asphaltene components have tendency to precipitate initially.