Characteristics of micro-scale pore structures of marine-continental transitional shale from the mid-eastern area,Qinshui Basin

In order to study the pore characteristics of the Permo-Carboniferous shale, some experiments including scanning electron microscope,nitrogen sorption-desorption experiments and mercury intrusion method were conducted to analyze the characteristics of the pore types,pore morphology,and pore size distribution. The results show that the nano-scaled pores in marine-continental transitional shale developed widely. Organic pores were the main pore type, and many intergranular pores with some intragranular pores were also found in the shale. The pores were mainly slit- shaped and parallel-plate. The meso-pores with the 2 -50 nm pore size distribution were the main body of the nano- scaled pores,and they made a major contribution to pore specific surface area and pore volume in a common content of over 60% . The micro-pores also provided a considerable value of the surface area. Organic pores were primarily the micro-pores,and the TOC content was an important controlling factor of BET surface area and BJH pore volume. The content of clay minerals with a large quantity of meso-pores also had an effect on the value of surface area and pore volume.