Abstract During the coalbed methane (CBM) exploration and development, in-situ stress and permeability are two vital reservoir evaluation parameters. In this work, with the injection/falloff well test and in-situ stress data of 11 CBM wells in the Hancheng area, eastern margin of the Ordos Basin, China, the distribution of in-situ stress and its influence on the coal reservoir permeability were investigated. Results show that the maximum (SH, 10.80–53.84 MPa) and minimum horizontal (Sh, 9.96–31.88 MPa), and vertical principal stresses (Sv, 14.37–36.46 MPa) increase with the increasing burial depth. However, the coal reservoir permeability (0.01–0.54 mD) shows a decreasing tendency accompanied by increasing stresses. Three stress fields (I, II, and III) between 532.28 and 1350.55 m could be divided: I is in a compression zone (〈700 m, SH〉Sh ≈ Sv, reverse or strike-slip stress regimes); II is in a tension zone (700–850 m, Sv > SH > Sh, normal stress regime); III is in a compression zone again (>850 m, SH > Sv > Sh, strike-slip stress regime). The top-down in-situ stress regimes result in a “decreasing - increasing - decreasing” permeability variation. Meanwhile, the lateral stress coefficient, stress ratios decreased slowly while the reservoir pressures and temperatures show a positive correlation with increasing burial depth.

中文翻译：

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鄂尔多斯盆地东缘韩城地区地应力分布及其对煤储层渗透率的影响

摘要 在煤层气勘探开发过程中，地应力和渗透率是两个重要的储层评价参数。本文利用鄂尔多斯盆地东缘韩城地区11口煤层气井的注入/衰减井试验和地应力数据，分析地应力分布及其对煤储层渗透率的影响被调查。结果表明，最大（SH，10.80-53.84 MPa）和最小水平（Sh，9.96-31.88 MPa）和垂直主应力（Sv，14.37-36.46 MPa）随着埋藏深度的增加而增加。然而，煤储层渗透率（0.01-0.54 mD）随着应力的增加呈下降趋势。532.28 到 1350.55 m 之间的三个应力场（I、II 和 III）可以划分：I 处于压缩区（<700 m，SH>Sh ≈ Sv，反向或走滑应力状态）；II 处于张力带（700-850 m，Sv > SH > Sh，正应力状态）；III 再次处于压缩带（>850 m，SH > Sv > Sh，走滑应力状态）。自上而下的原位应力状态导致渗透率变化“递减 - 递增 - 递减”。同时，侧向应力系数、应力比缓慢下降，而储层压力和温度与埋深增加呈正相关。