Adopted samples from the high-rank coal reservoirs in Southeast margin of Ordos Basin,through the stress sensitivity experiment of coal samples,stress sensitivity of coal reservoirs and the effects of effective confining pressure,fractures inside the coal and water condition on stress sensitivity were analyzed.The results show that,the permeability decreases according to negative exponential function with the increase of effective stress.When effective stress changes from 2.5 MPa to 10 MPa,dimensionless permeability of the coal samples is 0.10～0.28,and the average value is less than 0.15;the damage rates of permeability are 71.92%～90.14%,and the average value is 84.59%.When effective stress is less than 5 MPa,the coal reservoir permeability decreases rapidly with the increase of the effective stress,the stress sensitivity is the highest;when effective stress is between 5 MPa and 10 MPa,the stress sensitivity is medium;when effective stress bigger than 10 MPa,the decline of the permeability slow down,and the stress sensitivity is weak.The initial permeability of coal samples with fractures inside is higher,and the stress sensitivity is relatively small;the irreversible plastic deformation generated larger in the lifting-pressure process results in relatively high irreversible damage rates after the pressure decreas.The permeability of wet coal samples reduces rapidly with the increase of effective pressure,with the increase of moisture content,the stress sensitivity is more obvious.%采用鄂尔多斯盆地东南缘高煤级煤储层样品,通过煤样的应力敏感性试验,分析了煤储层应力敏感性及有效围压、煤中裂隙和含水情况等对煤储层应力敏感性的影响。研究结果表明：煤储层渗透率随有效应力的增加按负指数函数规律降低,当有效应力从2.5 MPa增加到10 MPa时,煤样无因次渗透率为0.10～0.28,平均低于0.15,渗透率损害率为71.92%～90.14%,平均为84.59%。在有效应力小于5 MPa时,煤储层渗透率随有效应力增加快速下降,应力敏感性最强;有效应力在5～10 MPa时,渗透率随有效应力增加而较快下降,应力敏感性较强;而当有效应力大于10 MPa后,渗透率随有效应力的增加下降速度减缓,应力敏感性减弱。含裂隙煤样初始渗透率较高,且应力敏感性相对较小;但在升压过程中产生不可恢复的塑性变形大,导致降压后不可逆损害率相对较高。同样,含水煤样的渗透率随有效应力的增加而快速下降,含水条件下的应力敏感性也更明显。
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