Pore Accessibility and Competition for Pore Space between Light Alkanes in Petroliferous Shales at the Wet-gas Thermal Maturity

Understanding petroleum in shale reservoirs is broadly relevant given the current emphasis on these resources in the U.S. and developing interest worldwide. Petroleum in shale reservoirs is stored in organic matter and mineral pore space. However, the pore size distribution of methane vs. higher alkanes in shales is unclear. We propose to examine pore accessibility and competition for open pore space between methane and ethane in a shale sample at the wet-gas stage of thermal maturity. Competition for available pore space in the sample will be assessed by monitoring adsorption of a methane/ethane mixture and comparing the results to the adsorption of methane only. We hypothesize that methane will prefer smaller pores fractionating ethane within larger pores. If true, this suggests that when assessing shale reservoirs for C2+ alkanes an understanding of fine porosity may be unimportant.