The current in situ stress regime is of great significance to the exploration and development of coalbed methane (CBM). In this study, the vertical stress (), maximum horizontal principal stress (), and minimum horizontal principal stress () in the Liupanshui Coalfield were studied. Variations of the maximum and minimum envelopes and trend lines of the lateral pressure coefficient () with depth were obtained, and the non-monotonic decrease of permeability with burial depth was determined. On this basis, the effect of in situ stress on the coal reservoir permeability was evaluated. The results show that the average vertical stress gradient of the main coal seam in the Liupanshui Coalfield is 0.024 MPa/m. Generally, there are two stress regimes of  >  >  (44.23%) and  >  >  (46.15%);  >  >  accounts for a smaller proportion (9.62%), and only occurs in relatively shallow coal seams (<622.85 m). In the range of the tested burial depths, for <600 m,  >  >  is dominant;  >  >  is dominant between 600 and 800 m; and between 800 and 980 m, the coal reservoir is affected by both  >  >  and  >  > , representing a transition zone between the two stress states. With the increase of burial depth, the permeability of the coal reservoir shows a complex non-monotonic decline, and the variation of the permeability of the coal reservoir differs under the influence of different stress regimes. Further analysis shows that under the background of stress regime transformation, permeability is mainly affected by the stress value, horizontal principal stress difference, stress regime, and coal cleat, indicating that in situ stress is the main controlling factor of coal reservoir permeability in the Liupanshui Coalfield.

中文翻译：

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黔西六盘水煤田地应力特征及其对煤层渗透率的影响

当前地应力状态对煤层气勘探开发具有重要意义。本研究对六盘水煤田的竖向应力（）、最大水平主应力（）和最小水平主应力（）进行了研究。得到了侧压系数( )的最大、最小包络线和趋势线随深度的变化，确定了渗透率随埋藏深度的非单调递减规律。在此基础上，评价了地应力对煤储层渗透率的影响。结果表明，六盘水煤田主煤层平均垂直应力梯度为0.024 MPa/m。一般来说，有两种应力状态 >   > (44.23%) 和 >   >  (46.15%)； >   > 占的比例较小（9.62％），并且仅在相对浅的煤层（<622.85米）发生。在测试埋深范围内，<600 m， >   > 占优势； >   > 是在600和800m主导; 800~980 m 之间，煤层受 >   > 和 >   > ，代表两个应力状态之间的过渡区。随着埋藏深度的增加，煤储层渗透率呈现复杂的非单调下降趋势，煤储层渗透率的变化在不同应力状态的影响下存在差异。进一步分析表明，在应力状态转换背景下，渗透率主要受应力值、水平主应力差、应力状态和煤割理的影响，表明地应力是六盘水煤储层渗透率的主要控制因素。煤田。