Reservoir Evaluation and Development ›› 2021, Vol. 11 ›› Issue (2): 184-189.doi: 10.13809/j.cnki.cn32-1825/te.2021.02.006

• Shale Gas Exploration • Previous Articles     Next Articles

Characteristics of supercritical adsorption and desorption of deep shale gas in South Sichuan

YANG Jian1(),ZHAN Guowei1,ZHAO Yong1,REN Chunyu2,QU Chongjiu2   

  1. 1. Research Institute of Petroleum Exploration and Development, Sinopec Southwest Oil and Gas Company, Chengdu, Sichuan 610041, China
    2. State Key Laboratory of Oil and Gas Resources and Prospecting, China University of Petroleum(Beijing), Beijing 102249, China
  • Received:2020-10-20 Online:2021-04-26 Published:2021-04-30

Abstract:

The adsorption capacity of shale gas is mainly influenced by the factors such as burial depth, mineral composition, temperature and pressure. The shale gas in South Sichuan has the characteristics of large buried depth, high temperature and high pressure. It has great significance to determine the adsorption and desorption characteristics of this kind of shale reservoir in supercritical state for the implementation of gas reservoir production. By the combination of indoor physical simulation experiments and molecular dynamics simulation, the composite characterization model of Illite and Kerogen is constructed and optimized, the multiple prediction model of whole area adsorption capacity of the deep shale gas in South Sichuan is developed, and the adsorption and desorption characteristics of the gas reservoir are clarified. The experimental results show that: with the increase of formation pressure, the adsorption capacity increases gradually, and when the pressure is higher than 15 MPa, the increase of adsorption capacity gradually slows down. Under the original conditions of gas reservoir, the adsorbed gas volume accounts for 20 % ~ 25 % of the total gas volume. When the formation pressure drops to 20 MPa, the recovery degree of free gas is about 70 % ~ 90 %, and the recovery degree of adsorbed gas is about 25 % ~ 40 %.

Key words: deep shale gas in South Sichuan, high temperature, high pressure, adsorption, desorption, prediction model, recovery degree

CLC Number: 

  • TE312