Characteristics and origin of coal reservoir pressure in the west C-uizhou area

Abstract：In order to identify the controlling factors in differential development of the coal res- ervoirs pressure in the west Guizhou area, the distribution character of the coal reservoir pressure was discussed in two levels, the whole region and tectonic unit. The effects of storage conditions, gas generating conditions, permeability and stress characteristic on the reservoir pressure were analyzed. The results show that the pressure systems of the coal reservoir in the study area are mainly normal （pressure coefficient 0.9--1.1） and high pressure（pressure coef- ficient p〉 1.1）. The pressure coefficient has a great difference in the same coal seam of differ ent tectonic unit and the different coal seam of the same tectonic unit. The reservoir permeabil ity and stress development characteristics, which affect the differential connectivity of the various sets of the coal reservoir and determine the level of reservoir pressure, are main reasons of regional differences in reservoir pressure. In the Panguan syncline, due co the good pressure preservation conditions, the differential development of the coal reservoir pressure is subject tothe impacts on gas-generating conditions, which also keep to the control law of permeability under the stress-led of the region.