The current study and development of organic matter pores in organic-rich shale

The organic matter pores (OM pores) were one important type of pores in organic-rich shale. In recent years, the researches about the formation mechanisms, development model and influencing factors on OM pores as well as their contribution to the storing of shale gas had been made great achievements by previous scholars. These studies showed that OM pores were nanoscale pore-throat systems mainly developed in the organic matters and they also were one of the main components to the total pores in shales. Based on the different standard of classification, they could be divided into (1) primary or in situ pores and secondary or migrated pores (formation mechanism), (2) within, between or at interfaces of OM particles (location), (3) in kerogen or bitumen (matrix), and (4) open or closed pores (opening degree). In general, the formation and development of OM pores may be the combination of thermal maturity, total organic carbon, maceral types, inorganic minerals, and burial-diagenesis that worked together and also were the important reservoir space to shale gas. But the thermal maturity and TOC should be the most important affecting factors to the formation and development of OM pores. Therefore, by summarizing the current study and development of OM pores in organic-rich shale, we could find that there were also some unclear and unresolved problems still existed. Thus, we should pay more attention on the research of OM pores in organic-rich shale, such as the following (1) uniform the standards of definition and classification on OM pores; (2) the optimal geological conditions for the formation of OM pores should be determined; (3) strengthen the research of OM pores under simulation experiments and actual geological situations together; (4) develop the quantitative analysis on OM pores on the basis of qualitative evaluation; and (5) the development mechanism, preservation, and connectivity of organic pores need to be further refined synthetically. These questions should be solved in the further research.