Rock cores provide essential data for the exploration, evaluation, and production of oil and gas reservoirs. Through measurement and analysis of porosity, permeability and fluid saturation from core samples, operators are better able to characterize pore systems in the rock and accurately model reservoir behavior to optimize production. In addition to rock matrix, core samples contain formation fluids. These formation fluids will typically contain a mixture of hydrocarbons and brine which must be completely removed from the pore spaces of the rock for analysis. Soxhlet is the standard method used for rock core cleaning. Alternatively, the rock cores can also be cleaned using Pressurized Solvent Extraction.
For this Application Note a rock core sample was extracted using the UniversalExtractor E-800 with a Soxhlet warm method with sequential extractions using toluene, methanol and again toluene to extract all petroleum components while leaving the core intact. The remaining intact core can then be analyzed for characteristics such as porosity and permeability, while the extracted petroleum is not of interest.