Calculation of gas content in coal seam influenced by in-situ stress grads and ground temperature

On the basis of the analysis of coal bed gas pressure in deep mine, and the coal bed permeability ( k ) and the characteristic of adsorption parameter ( b ) changing with temperature, the author puts forward a new calculating method of gas content in coal seam influenced by in situ stress grads and ground temperature. At the same time, the contrast of the measuring results of coal bed gas pressure with the computing results of coal bed gas pressure and gas content in coal seam in theory indicate that the computing method can well reflect the authenticity of gas content in coal seam,and will further perfect the computing method of gas content in coal seam in theory,and have important value in theory on analyzing gas content in coal seam and forecasting distribution law of gas content in coal seam in deep mine.

Research into selection evaluation system on co-mining of“the three gas”in coal series stratum

Along with the continuously go deep into of the research on coal series stratum,unconventional coalderived gas gets more attention,including coalbed methane,shale gas and tight sandstone gas.However,selection evaluation as the basis and prerequisite for the exploration and development of unconventional coal-derived gas has great significance.The purpose of this paper is to set up a selection evaluation system,and this system is called selection evaluation on co-mining of“the three gas”in coal series stratum.If a basin exists these three gases at the same time,then we can use this evaluation system to evaluate this type of basin and choose dessert area,finally,for co-mining of“the three gas”in coal series stratum provide guidance.By choosing the main control factors of coalbed methane,shale gas and tight sandstone gas,and based on fuzzy mathematics,analytic hierarchy process theory and multilevel fuzzy comprehensive evaluation theory to research selection evaluation system on co-mining of“the three gas”in coal series stratum.Finally,26 main control factors are selected,and then the index system is set up;in addition,by calculating the weight and establishing the membership function and evaluation set,and then selection evaluation system on co-mining of“the three gas”in coal series stratum with a four layer index is established.This paper can provide a theoretical basis and engineering guidance for unconventional gas exploration and development.