Comparison of Pore Characteristics and Constraints of Marine-Terrestrial Mud Shale

Based on low temperature nitrogen adsorption experiment, the quantitative characterization of Marine mud shale from Qiongzhusi formation of the lower Cambrian and Longmaxi formation of the lower Silurian in the Upper Yangzi Massif and Terrestrial mud shale of chang 9 and chang7 oil layers in Ordos Basin is finished. The pore characteristics and influencing factors of shale reservoirs with different sedimentary environments and maturity are discussed systematically from the aspects of material composition and thermal evolution. The results show that the brittle mineral content is negatively correlated with the specific surface area and pore volume. The content of clay minerals is weakly positively correlated with specific surface area and pore volume. TOC content is weakly positively correlated with pore volume, strongly positively correlated with specific surface area, and not correlated with average pore diameter. With the increasing of Ro, the average pore diameter decreases, and the decreasing speed decreases with the increasing of Ro. When Ro is between 0.5% and 2.8%, the specific surface area increases with Ro. When Ro is between 2.8% and 5%, the specific surface area decreases with the increase of Ro. The pore volume was negatively correlated with Ro value due to the decrease of pore diameter.