Reservoir Evaluation and Development ›› 2020, Vol. 10 ›› Issue (5): 1-11.doi: 10.13809/j.cnki.cn32-1825/te.2020.05.001

• Specialist Forum •     Next Articles

Evolution and implications of shale pore structure characteristics under different preservation conditions

LIU Shugen1,2(),YE Yuehao1,RAN Bo1,JIANG Lei3,LI Zhiwu1,LI Jinxi1,SONG Jinmin1,JIAO Kun1,LI Zeqi1,LI Yuwei4   

  1. 1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, CDUT, Chengdu, Sichuan 610059, China
    2. Xihua University, Chengdu, Sichuan 610039, China
    3. Guangdong University of Petrochemical Technology, Maoming, Guangdong 525000, China
    4. Sinohydro Bureau 7CO., LTD, Chengdu, Sichuan 611730, China
  • Received:2020-06-10 Online:2020-10-26 Published:2020-09-24


Because of the importance of preservation conditions and shale pore evolution to shale gas exploration and development, it is of great scientific significance and academic value to study the relation between them. The pore structure characteristics and evolution of black shale with different preservation conditions have been studied by means such as argon ion polishing, scanning electron microscope and nitrogen adsorption, and it is found that the pore structure of black shale under different preservation conditions are significantly different. This difference is caused by the difference of preservation conditions in the late uplift process, which is manifested in the following aspects. First, inorganic pores in black shale with good or bad preservation conditions are both less developed, and most of the original intergranular pores are filled with generated hydrocarbons. The inorganic pore characteristics between them are basically similar. Second, the organic pores in black shale are of great difference under different preservation conditions. The diameter of shale organic pores is larger in good preservation conditions, which are in round or bubble shape. While the organic pores are relatively smaller in diameter or totally absent in poor preservation condition, which are in flat or irregular shape with the certain characteristics of flattening and deformation. Third, the pore volume and specific surface area of the black shale under good preservation conditions are better than that under poor conditions. Fourth, the porosity evolution of black shale is affected by preservation conditions. The original pore morphology and distribution are controlled by facies and diagenesis process, and so are the organic matter(oil) distribution form. Thermal evolution of organic matter(oil cracking) influences the existence of organic pores. Whereas, in the late uplifting process, the pore structures(shape, size, pore volume) are affected by the quality of the preservation condition. Therefore, the size, morphology and porosity of the shale organic pores reflect the preservation conditions of shale gas in some extent.

Key words: Longmaxi Formation shale gas, preservation conditions, pore structure, pore evolution

CLC Number: 

  • TE311