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

• Published in: 煤炭学报：英文版 2012, Vol.18 (4), p.362-367
• Main Author: GAO Li-jun TANG Da-zhen XU Hao MENG Shang-zhi ZHANG Wen-zhong MENG Yan-jun WANG Jun-jian
• Format: Article
• Language: English
• Subjects: CBM; 临界解吸压力; 地质参数; 控制因素; 气体生产; 煤层气井; 煤层甲烷; 生产力
• ISSN: 1006-9097

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 break- through for 100 days. Second, two parameters, which include potential of gas production and gas production capacity, were bet- ter than the single parameter, such as gas content, coal thickness, and penetration to analyze affecting factors of single well pro- duction. 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.