Gas coal hydrofracture field time-space monitoring device and method

Abstract

The invention discloses a gas coal hydrofracture field time-space monitoring device and method. The device comprises a main cavity body, a crustal stress simulation module, a gas charging and discharging module, a hydrofracture module and a resistivity testing module which are arranged on the main cavity body, wherein the crustal stress simulation module is used for simulating the stress state of a coal body under a filed condition; the gas charging and discharging module is used for charging gas into a coal body; the hydrofracture module is used for providing pressure water for the coal body; the resistivity testing module is used for testing resistivity signals in a hydrofracture process of a coal sample. A coal sample obtained at the field is put into the main cavity body of the device, and gas is charged into the main cavity body, so that the coal sample adsorbs the gas fully, and external load is applied; high-pressure salt water is injected into preset drill holes in the coal sample and the preset drill holes are fractured; meanwhile the resistivity variation in the coal sample in the process is tested; the distribution in a three-dimensional space and the time-space evolution process of a fracture of the coal body are monitored continuously by the sensitive response to the salt water by resistivity. Additionally, the device also can determine the reasonable water injection pressure of the coal sample under different conditions.

Description

technical field [0001] The invention relates to a time-space monitoring device and method for gas coal hydraulic fracturing fissure field, which belongs to the field of coal mine gas disaster prevention and coal mine safety technology, and is especially suitable for measuring the effective action area of ​​hydraulic fracturing anti-permeability measures in gas-containing coal. and methods. Background technique [0002] my country is rich in coal resources, but the occurrence conditions of coal seams vary greatly. There are many gas-containing coal seams and large gas reserves. High gas and coal and gas outburst mines account for more than 50% of the total number of mines. But with the efficient intensification of coal production and the increase of mine mining depth, the amount of gas gushing out is increasing, and the threat of coal and gas outburst and gas explosion is becoming more and more serious. Gas disasters have become the most important factor restricting the safe...

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Problems solved by technology

[0004] However, the current evaluation of the effect of hydraulic fracturing only stays in very traditional means, such as examining the traditional indicators such as drilling cuttings and water content and examining the effect of gas drainage.

These parameters are all "point evaluation" of the potential impact area of ​​hydraulic fracturing, that is, by taking cores from fixed locations in the potential impact area of ​​hydraulic fracturing to test the relevant parameters and then evaluate whether hydraulic fracturing affects this point, it is impossible Achieving a comprehensive and continuous spatiotemporal evaluation of the evolution of the coal and rock mass structure in the area will inevitably lead to blindness in effect inspection and later gas drainage construction, which will not only affect the safe production of coal mines, but also lead to a substantial increase in construction costs

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