The pore characteristics and gas potential of the Jurassic continental shales in the middle-small basins, northwest China

Abstract Jurassic continental shales were extensively developed in the northwest of China. To characterize and analyze the pores and gas potential of these shales, geochemical, mineralogical, petrophysical, and methane adsorption capacity (MAC) experiments were performed on 10 samples. The results indicated that these shales have a high total organic carbon (TOC) content, low porosity and permeability. Interparticle pores between clay platelets are dominant. Organic matter (OM) pores cannot be observed using scanning electron microscope. The methane adsorption capacity is strong, and it is controlled by TOC content. Strong MAC indicated the shales have an excellent capacity of storing gas. In addition, type III organic matters can generate amount of gas at a lowly mature stage. Therefore, it is speculated that the studied shales have a good gas potential, which is supported by canister desorption results.