Reservoir Evaluation and Development ›› 2021, Vol. 11 ›› Issue (2): 154-163.doi: 10.13809/j.cnki.cn32-1825/te.2021.02.003

• Shale Gas Exploration • Previous Articles     Next Articles

Micro pore structure characterization and classification evaluation of reservoirs in Weirong Deep Shale Gas Field

XIONG Liang1(),PANG Heqing1(),ZHAO Yong1,WEI Limin1,ZHOU Hua1,CAO Qian2   

  1. 1. Research Institute of Exploration and Development, Sinopec Southwest China Oil and Gas Company, Chengdu, Sichuan 610041, China
    2. Keyuan Engineering Technology Testing Center of Sichuan Province, Chengdu, Sichuan 610091, China
  • Received:2020-10-20 Online:2021-04-26 Published:2021-04-30
  • Contact: PANG Heqing;


In order to study the evaluation standard of deep shale reservoirs, their micro pore characteristics have been studied. Based on the ideas of micro pore structure research with “high precision and cross scale”, and by using nitrogen adsorption, high pressure mercury injection, scanning electron microscope and mineral analysis electron microscope experiments, a series of quantitative characterization techniques of reservoir micro pore structure with full pore size range are formed, and the evaluation standard of deep shale gas reservoir is established. The research results show that: ①The pore types include organic pore, intergranular pore, intragranular pore and microfracture, which are of great difference with each other. The organic pores are dominant with the surface porosity more than 50 %, the pore morphology is complex with the distribution of elliptic, irregular or flat, the shape coefficient is 0.50~0.90, and the fractal dimension(D) is 2.72~2.92. ②Based on the full pore size characterization technology and fractal theory, the pore structure can be divided into four types. The organic pores of type Ⅰ pore structure are developed (organic pore ratio Is greater than or equal to 50 %), well sorted (sorting coefficient Is greater than or equal to 0.7), large coefficient of variation (variation coefficient Is greater than or equal to 1.1), and multi-modal distribution of pore size. ③According to the classification of pore structure and reservoir parameters, shale reservoirs are divided into four types. The key parameters make up the structure of type Ⅰ are TOC≥4 %, total gas content Is greater than or equal to 6 m3/t, porosity Is greater than or equal to 6 %, brittle mineral content Is greater than or equal to 50 %, Young’s modulus Is greater than or equal to 36 GPa, Poisson’s ratio Is less than or equal to 0.225, and type Ⅰ pore structure. This kind of reservoir is mainly distributed in 2—31 layers, which is the optimal target window position.

Key words: Weirong Deep Shale Gas Field, Wufeng-Longmaxi Formation, micro pore structure characterization, fractal theory, evaluation criterion

CLC Number: 

  • TE122