Probable mechanism of organic pores evolution in shale: Case study in Dalong Formation, Lower Yangtze area, China

Organic pores structures and their probable evolution mechanisms were analyzed by an Ar-ion milling (SEM) after a thermal simulation experiment. Several kinds of organic pores including girdle pores, circular pores, and spongy pores appeared during the thermal simulation process. The result shows that there are different possible mechanisms in organic pores evolution. Girdle pore is a typical pore structure in a particular period of hydrocarbons generation, and the girdle structure is an organic matter-mineral complex where the hydrocarbons generate. This phenomenon made it possible to observe the organic matter-mineral complex for the first time.