The Open Petroleum Engineering Journal

2016, 9 : 289-298
Published online 2016 December 26. DOI: 10.2174/1874834101609010289
Publisher ID: TOPEJ-9-289

RESEARCH ARTICLE
 Analysis on Production of Coal Bed Methane Considering the Change in Permeability of Coal Rock

Zhu Likai1,2 , Ji Youjun3,4, * , Yang Tianhong1 and Li Xiaoyu3

* Address correspondence to this author at the State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Southwest Petroleum University), Chengdu, 610500, China; Tel: +86 18380172978; E-mail: .jiyoujun0319@163.com

ABSTRACT

Based on the mechanism of migration of the coal bed methane (CBM), and taking into account the deformation of the coal rock during the process of CBM production was also taken into account, a coupled mathematical model considering the interaction of solid and fluid for methane extraction was built. The coal gas extraction of JINcheng coal mine was taken as an example, some typical coal sample was chosen to test the permeability under different confining pressure. The curve for permeability of coal rock versus effective stress under different confining pressure was obtained, a numerical model considering the variation of permeability for methane extraction was set up. The influence of deformation of coal rock on the gas production was simulated and analyzed. The simulation results indicate that the productivity curve considering deformation of rock is closer to the actual production data, at the initial stage of production, the gas rate is less than the case without considering deformation of rock, but the time of stable yield will last longer, and this matches the actual methane extraction, therefore, we recommend that the deformation of coal seam should be considered during the prediction of methane production for JINcheng coal mine.

Keywords:

Deformation, Methane, Numerical Simulation, Prediction for production of CBM.