Extraction of Hydrocarbons from Soil and Rocks Using High Pressure Carbon Dioxide

Carbon dioxide at elevated pressure and temperature is a powerful solvent capable of extracting hydrocarbons from rocks, soil and mud slurries, which are by-products of large numbers of oil industries. The objective of this study was to investigate the effects of water content and grain size and type on the extraction capacity of CO2 (at 300 bar and 120 oC) and on the composition of extracted hydrocarbons.<br>The results of this study indicate that CO2 at 300 bar and 120 oC is an effective solvent, which leads to high oil recoveries, except for reservoirs with high water contents (≥20%). The results also show that the extraction efficiency of CO2 from soil is higher than that from limestone particles of the same size and distribution, indicating that Bu Hasa oil holds more strongly to the limestone particles than to the soil particles. Moreover, the compositional analysis show that CO2 at 300 bar and 120 oC is capable of extracting hydrocarbons up to C31 including gasoline and diesel range hydrocarbons. <br>