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以沁水盆地南部某区块煤样为实验对象,利用非稳态法测定气驱水和水驱气情况下气和水的相对渗透率。结果表明:水驱气实验中,经过不同驱替压力、不同气体的水驱气相对渗透率实验后,煤样的束缚水饱和度在每次实验后均发生不同程度的变化。气的相对渗透率均小于水的相对渗透率。分析为煤样在高压吸附气体作用下变得更加具有亲水性,如甲烷、二氧化碳。但对于非吸附气体氦气,高压反而阻止了水渗流至小空隙,导致束缚水饱和度的下降。气驱水实验中:测定并计算得到的数据相对分散,不具有一定的规律,气和水相对渗透率曲线波动大。研究认为煤层中气和水的相对渗透率取决于煤层中气体的性质、煤层内压力以及各相流体与煤层的相互作用。
Taking the coal samples of a block in the southern part of Qinshui Basin as the experimental object, the relative permeability of gas and water under gas flooding and water purging was measured by the unsteady method. The results show that the irreducible water saturation of coal samples varies with different degrees after water displacement experiments with different displacing pressures and relative gas permeability of different gases. The relative permeability of gas is less than the relative permeability of water. Analysis of coal samples become more hydrophilic under the action of high pressure adsorbed gas, such as methane, carbon dioxide. However, for non-adsorbed gas helium, the high pressure instead prevents water seepage to small voids, resulting in a decrease in irreducible water saturation. In the gas-flooding experiment, the measured and calculated data are relatively scattered and do not have certain rules, and the relative permeability and gas-water permeability curves fluctuate greatly. The study suggests that the relative permeability of gas and water in a coal seam depends on the nature of the gas in the coal seam, the pressure in the coal seam, and the interaction of the fluids in each phase with the coal seam.