A method for pre-cracking and weakening of hard overlying rock under aquifer to control the height of water-conducting fracture zone

Abstract

The embodiment of the present application discloses a method for pre-cracking and weakening the hard overlying rock under the aquifer to control the height of the water-conducting fracture zone, which relates to the technical field of coal mining and is invented for the convenience of improving the recovery rate of coal resources. The method includes: obtaining the structural characteristics of the overlying rock between the main coal mining seam and the aquifer of the working face; determining the type of the overlying rock and the distribution position of the key layer for crack control according to the structural characteristics of the overlying rock; Predict the failure height of the overlying rock of the main coal mining seam before pre-splitting; based on the predicted failure height of the overlying rock, combined with the spatial relationship between the main mining coal seam and the aquifer, determine the control height of the water-conducting fracture zone after the pre-splitting of the roof is weakened; Within the control height range of the water-conducting fracture zone, determine the pre-cracking weakening target layer and the pre-cracking weakening range; adopt the hydraulic fracturing method, within the determined pre-cracking weakening range, pre-crack the determined pre-cracking weakening target layer Fracture weakening operation. The embodiment of the present application is applicable to the pre-splitting and weakening operation of the pre-splitting and weakening target layer.

Description

technical field [0001] The application relates to the technical field of coal mining, in particular to a method for controlling the height of a water-conducting fracture zone by pre-cracking and weakening the hard overlying rock under an aquifer. Background technique [0002] Coal accounts for more than 60% of my country's primary energy production and consumption structure for a long time. The geological mining conditions and hydrogeological conditions of my country's coal mines are varied and complex. According to incomplete statistics, my country's coal reserves threatened by water damage account for about 27% of the proven reserves. The problem of water damage prevention and control is becoming more and more prominent, and the development of overlying rock damage is highly dependent on the safety of water bodies. The key parameters of borehole design, water conservation coal mining scheme design, and water prevention and control measures are an important basis for solving...

AI Technical Summary

Problems solved by technology

[0003] At present, the control of overlying rock damage is mainly from the aspects of mining method, mining thickness, and working face design. Methods such as thickness-limited mining, strip mining, filling mining, and shortening the length of the working face are adopted to control the impact of mining, so as to reduce the overlying rock damage height. , but these overburden failure control methods sacrifice the recovery rate and mining efficiency, resulting in a low recovery rate of coal resources

Images