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Geological Journal of China Universities ›› 2023, Vol. 29 ›› Issue (4): 644-656.DOI: 10.16108/j.issn1006-7493.2021118

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Research on the Control of CBM Well Reservoir Geological Engineering Characteristics on Productivity

LI Quanzhong1,2,3,SHEN Jian3,4,HU Haiyang5*,JI Xiaofeng6   

  1. 1. Mining Engineering Department, Shanxi Institute of Technology, Yangquan 045000, China;
    2. The Cultivation Base of Shanxi Key Laboratory of Mining Area Ecological Restoration and Solid Wastes Utilization, Shanxi Institute of Technology, Yangquan 045000, China;
    3. School of Resources and Geosciences, China University of Mining and Technology, Xuzhou 221116, China;
    4. Key Laboratory of Coalbed Methane Resource & Reservoir Formation Process, Ministry of Education, China University of Mining &Technology, Xuzhou 221008, China;
    5. Guizhou Research Center of Shale Gas and CBM Engineering Technology, Guiyang 550081, China;
    6. Taiyuan University of Science and Technology, School of Energy and Materials Engineering, Taiyuan 030024, China
  • Online:2023-08-15 Published:2023-08-15

Abstract: In order to improve the single well gas production of CBM well,the influencing factors of CBM well gas production are studied from the geological static parameters and engineering dynamic parameters of CBM development. Based on a block of Shanxi Qinshui Basin 12 reservoir parameters and geological characteristics of typical CBM Wells and development data, starting from the geological control factors, engineering control, detailed analysis of seven aspects of 24 kinds of factors, including coal bed methane resource characteristics,coal reservoir seepage characteristics,structures,energy,drilling,fracturing,drainage,we study the degree to which these factors control the CBM gas production. The results show that the gas production of CBM Wells in the same block is different, which is affected by both geological factors and engineering factors; Also, coalbed methane resources and coalbed methane reservoir seepage, structures and energy characteristics clearly influence coalbed methane production, and when the permeability of coalbed methane reservoir is more than 0.7 mD,it is favorable for coalbed methane well to yield increased gas production. In addition, faults affect the gas content of coal reservoir and fluid migration in the process of drainage and production. In the development of CBM, faults should be avoided and a safe distance of 400 m should be maintained. Furthermore, the higher the casing pressure and gas release pressure of CBM well,the more conducive to expanding the desorption radius of coal reservoir, which results in high and stable production of a CBM well. The scale of fracturing operation in coal reservoir also has great influence on gas production, and the scale of fluid injection is more significant than that of sand injection in the study area. The pressure drop rate and gas production rising rate should be reasonably controlled in each stage of CBM well, and the pressure drop rate should be controlled within 10 kPa/d in the pressure control and production raising stage. These will allow to enlarge the pressure drop funnel radius of Coal Reservoir. The analysis of the geological and engineering
factors of CBM Wells in the study area provides a theoretical basis for the geological selection and geological selection of CBM. It
may also serve as technical guidance for the development of other CBM projects. 

Key words: CBM wells, geological engineering, coal structure, fracturing scale, production of aquatic gas, drop rate

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