Coal Reservoir Parameters And Its Control To Productivity Of Coalbed Methane Wells In The Southern Qinshui Basin

Based on coalbed methane exploitation in the Southern Qinshui Basin, used multidisciplinary theories and approaches in the fields of coal geology, oil & gas geology and hydrologic geology, researched systematically on coal reservoir parameters, such as coal reservoir thickness, gas content, permeability, desorption characteristics, geological structures, in-situ stress conditions and hydrology conditions, the correlativity and model have been established between coalbed methane wells' productivity and those parameters in this dissertation. The isothermal adsorption and desorption experiment revealed that coal seam has desorption hysteresis in the process of desorption. In the pressure swing adsorption curve, the desorption curve is up from the adsorption one. Initial phase of desorption, desorption curve slope is less than adsorption's, therefore, the real coalbed methane wells' productivity is below the one expected from adsorption curve. The quantification relationship between coal reservoir parameters and in-situ stress following the burial depth has also been discussed in this dissertation. The law which coal reservoir permeability decreases exponentially with the increase of burial depth is summarized. In the dissertation, coalbed methane wells' productivity is affected by hydrogeology parameters like water reserve of coal seam, original water pressure or mine roof and base lithology. The research result has important directive significance to coalbed methane exploitation.