Microstructural characteristics of the Cretaceous Qingshankou Formation shale, Songliao Basin

To research the characteristics and petroleum geological significance of micro pores, this paper uses Second Electron Microscope (SEM) and secondary SEM imaging capability in Field Emission SEM (FE-SEM) to characterize shale from the first member of the Cretaceous Qingshankou Formation, Songliao Basin. There are five major pore types in the shale, including matrix intercrystal, organic, dissolution, interparticle, and intracrystalline pores. In addition, there are a mass of micro-fractures of micron-submicron (nano-) scale, including dissolution, filled and interlayer fractures. The existence of complex fracture-pore systems provides an effective pathway for primary migration and it also provides ample storage space for the residual petroleum in shale, which is important for the primary migration and storage for shale oil and gas resources.