Characteristics of in situ stress and its influence on coal seam permeability in the Liupanshui Coalfield, Western Guizhou

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