Title: Geological controls on coalbed methane accumulation and optimisation strategy for gas productivity: a case study in eastern Ordos Basin, China

Authors: Kui Zhu; Xinyi Song; Fan Lu; Bo Jiang; Changshen Wang; Guoyong Yang; Zhengjie Chen

Addresses: Key Laboratory of CBM Resources and Reservoir Formation Process, The Ministry of Education, Xuzhou 221116, China; School of Resources and Earth Science, China University of Mining and Technology, Xuzhou 221116, China ' School of Resources and Earth Science, China University of Mining and Technology, Xuzhou 221116, China; State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China ' Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, China ' Key Laboratory of CBM Resources and Reservoir Formation Process, The Ministry of Education, Xuzhou 221116, China; School of Resources and Earth Science, China University of Mining and Technology, Xuzhou 221116, China ' School of Resources and Earth Science, China University of Mining and Technology, Xuzhou 221116, China ' School of Resources and Earth Science, China University of Mining and Technology, Xuzhou 221116, China ' School of Resources and Earth Science, China University of Mining and Technology, Xuzhou 221116, China

Abstract: Drainage conditions can significantly affect the coalbed methane (CBM) production, which is accomplished by reducing the gas partial pressure in the coal seam. This can be achieved by pumping the formation water or gas injection. In this study, the Baode region is selected to study the drainage conditions and production characteristics on the early stage of CBM production. The temporal trends of water production, wellhead pressure and gas production have been analysed. Results show that the favourable burial depth for CBM accumulation between 500 and 700 m. Sandy mudstone and mudstone are beneficial to CBM preservation. The wellhead pressure should be maintained between 0.4 MPa and 1.0 MPa, and the optimal range of wellhead pressure lies between 0.5 and 0.8 MPa for stable production. The gas production increases with increased water production when the wellhead pressure has become progressively stable in the middle phase of early stage. [Received: September 9, 2018; Accepted: October 24, 2018]

Keywords: coalbed methane production; water production; wellhead pressure; gas production.

DOI: 10.1504/IJOGCT.2020.108050

International Journal of Oil, Gas and Coal Technology, 2020 Vol.24 No.4, pp.573 - 592

Accepted: 24 Oct 2018
Published online: 02 Jul 2020 *

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