西南石油大学学报(自然科学版) ›› 2020, Vol. 42 ›› Issue (2): 110-117.DOI: 10.11885/j.issn.1674-5086.2019.03.29.02

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A New Method for Rapid Evaluation of Shale Gas Content

LIANG Hongbin1, ZHANG Liehui1, CHEN Man2, ZHAO Yulong1, XIANG Zuping3   

  1. 1. State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China;
    2. Sichuan Changning Natural Gas Development Co. Ltd., Chengdu, Sichuan 610500, China;
    3. School of Petroleum Engineering, Chongqing University of Science & Technology, Shapingba, Chongqing 401331, China
  • Received:2019-03-29 Online:2020-04-10 Published:2020-04-10
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Abstract: It is important to make clear the variation rule of shale gas content for make reasonable development plan of gas reservoir. However, it is difficult to obtain the characteristics of shale gas content as adsorbed gas flow with free gas after desorption during the development. Due to the influence of environment, equipment and human factors, the interpretation results based on the two common methods of logging interpretation and field desorption have great errors, which brings trouble to research on the development theory of shale gas reservoirs. Therefore, the physical model for shale gas isothermal adsorption experiment based on volume method is established by using Horsfield filling theory, and the method to determine the proportion of adsorbed gas and free gas is proposed. This method is verified to be feasible based on the measured data. Compared with well logging interpretation method and field desorption method, this method is more concise and accurate, and easier to calculate. Furthermore, the variation characteristics of adsorption gas and free gas can be quantitatively described by this method during the reservoirs development. The results show that when the reservoir pressure decreases significantly and the main gas source in the pore changes from free gas to adsorbed gas, the corresponding pressure of transition point is negatively linearly correlated with the porosity.

 

Key words: shale gas, gas content, adsorbed gas, free gas, desorbed gas

CLC Number: