EFFECTS OF GEO-STRESSES TO PERMEABILITY RATE OF LOW PERMEABLE ROCK AT DIFFERENT DEPTHS

In recent years, groundwater contamination can be caused by deep geological disposal of nuclear waste, CO2 deep geological disposal, landfills, hydroelectric reservoir leakage, oil pipeline leakage, which is attracted much attentions. The safety and reliability of these projects are closely related with the low-permeability rock. For this problem, the low permeability of shale is studied with hydraulic fracturing method to measure stress and water pressure test method for measuring rock permeability. The results show that: (1)Stress value of the study area shows an increasing trend with the depth of the hole, in line with the general distribution of stress; (2)Rock permeability decreases with depth. From 0 to 100m deep, water permeability changes greatly. From 100 to 400m deep, water permeability changes little. From 400 to 600m deep, the rock permeability rate remains at a relatively stable order of magnitude. According to regression analysis, the rock permeability rate and depth of the hole have a good negative exponential relationship. (3)Rock permeability and geo-stress have a negative exponential relationship. The impact of geo-stress on the rock permeability is a certain difference at different regions. This is consistent with the findings of other scholars. It forms the foundation for future research on seepage of low-permeability rock.