摘要
文中对临汾区块33口煤层气探井主力煤层水力压裂获得的地应力数据进行了分析，认为该煤层储层压力、破裂压力和闭合压力均与煤层埋藏深度呈线性正相关关系。1 070 m以上，煤层地应力状态以垂直应力（σv ）大于水平最大主应力（σH）大于水平最小主应力（σh）为主，最小主应力小于15 MPa，煤层处于伸张状态；1 070～1 200 m，煤层地应力状态转化为水平最大主应力，约等于垂直应力，约等于水平最小主应力，最小主应力15～20 MPa，煤层由伸张状态向挤压状态过渡；1 200～1 500 m，煤层地应力状态转化为水平最大主应力，约等于垂直应力大于水平最小主应力，最小主应力大于20 MPa，煤层处于挤压状态。随着煤层最小地应力的不断增大，煤层的渗透性不断下降，裂缝逐渐减小，趋于闭合；煤层最大水平主应力方向主要为NEE方向。
Abstract
The in-situ stress data of upper main coal seam for 33 coalbed methane exploration wells in Linfen Block were analyzed. It is considered that the reservoir pressure, fracturing pressure and closure pressure of this coal seam have a linear positive correlation with the depth of coal seam. When the coal seam is 1,070 m, in-situ stress state mainly shows as σv > σH > σh, the minimum horizontal principal stress is below 15 MPa and coal seam is in a tension state; when the coal seam is 1,070-1,200 m, in-situ stress transforms into σH≈σv≈σh, the minimum horizontal principal stress is 15-20 MPa, coal seam transforms from tension zone into compression zone; when the coal seam is 1,200-1,500 m, in-situ stress state is σH≈σv >σh, the minimum horizontal principal stress is over 20 MPa, in-situ stress state becomes compression zone. As the minimum in-situ stress of coal seam continually increases, the permeability drops rapidly, fractures reduce and tend to closed gradually. The direction of maximum horizontal principal stress is mainly NEE.
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