Geologically controlling factors on coal bed methane (CBM) productivity in Liulin

• Published in: Journal of coal science & engineering, China Vol. 18; no. 4; pp. 362 - 367
• Main Authors: Gao, Li-jun, Tang, Da-zhen, Xu, Hao, Meng, Shang-zhi, Zhang, Wen-zhong, Meng, Yan-jun, Wang, Jun-jian
• Format: Journal Article
• Language: English
• Published: Heidelberg China Coal Society 01.09.2012
• Subjects: Earth and Environmental Science; Earth Sciences; Geochemistry; Geology; Geophysics/Geodesy; Geotechnical Engineering & Applied Earth Sciences; Mechanical Engineering; ratio of critical desorption pressure to reservoir pressure; gas deliverability; geological factors; production capacity; Liulin; potential of gas production; CBM
• ISSN: 1006-9097; 1866-6566
• DOI: 10.1007/s12404-012-0405-4

It is of great significance to forecast high yield of CBM wells and analyze dynamic production by having an overall study on the characteristics of the produced CBM and determining the main factors influencing the productivity of CBM. With the test report and the related geological parameters of a single well, methods of combining the productivity data and typical production curves were used to analyze different geological factors and how to influence the capacity of a single layer. Then, the paper proposed a new understanding about capacity characteristics of the study area and geological control factors: First, the Shanxi formation production capacity characteristics was divided into two-stages, showing signs of gas and gas breakthrough for 100 days. Second, two parameters, which include potential of gas production and gas production capacity, were better than the single parameter, such as gas content, coal thickness, and penetration to analyze affecting factors of single well production. Finally, comprehensive analysis concluded that the ratio of critical desorption pressure to reservoir pressure has greater influence on the production of vertical CBM wells. Besides, the potential of gas production capacity has greater impact at stage of showing gas signs; the coal reservoir pressure and gas production capacity have greater impact at stage of gas breakthrough for 100 days. Thus, to seek the coal bed methane with high ratio of critical desorption pressure to reservoir pressure and high yield of gas will be important guarantee to the success of the coal bed methane exploration and development.