Title: Investigation of the factors causing the coalbed methane production differences in Shizhuangnan Block, Southern Qinshui Basin, North China

Authors: Guoqiao Yang; Shuheng Tang; Songhang Zhang; Zhongcheng Li

Addresses: Wuxi Research Institute of Petroleum Geology, RIPEP, SINOPEC, Wuxi 214126, Jiangsu, China; State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Wuxi 214126, Jiangsu, China ' China University of Geosciences, Beijing 100083, China ' China University of Geosciences, Beijing 100083, China ' China United Coalbed Methane Corporation Ltd., Beijing 100011, China

Abstract: The geology and engineering characteristics are investigated in the Zaoyuan area of the Shizhuangnan Block, Southern Qinshui Basin to determine variations in the water/gas production not only amongst regions, but wells within the same region. Using geophysical logging, hydraulic fracturing and production data, it appears that a roof/floor with low shale content may be the cause of excessive water production when a coal reservoir predominantly develops horizontal fractures due to hydraulic fracturing. Maintaining a slowly bottom hole pressure decline rate before gas production and stable after producing gas is favourable for the extension of the pressure drop funnel. This is also more likely to help wells have high gas production over their lifetime. Whether or not a coal reservoir depressurises fully is crucial for gas production in both north and south regions. [Received: October 19, 2017; Accepted: July 5, 2018]

Keywords: coalbed methane; CBM; Qinshui Basin; coal seam roof/floor; hydraulic fracture; drainage system.

DOI: 10.1504/IJOGCT.2020.107024

International Journal of Oil, Gas and Coal Technology, 2020 Vol.24 No.2, pp.289 - 304

Received: 19 Oct 2017
Accepted: 05 Jul 2018
Published online: 01 May 2020 *

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