Supercritical carbon dioxide fracture-creepage-seepage test device for high-temperature high-pressure coal petrography

Abstract

The invention discloses a supercritical carbon dioxide fracture-creepage-seepage test device for high-temperature high-pressure coal petrography. The device comprises a triaxial cell, a supercriticalcarbon dioxide generator system, an axle load and confining pressure loading system, an acoustic emission monitoring system, a temperature rise control system, a deformation-pressure monitoring systemand a permeability measuring system. The device is capable of realizing the supercritical carbon dioxide fluid fracture test of coal petrography under high temperature and high pressure, monitoring and recording the temperature and pressure changes of supercritical carbon dioxide and characteristics of fracture cracking and extension in the supercritical carbon dioxide fracture process in real time, monitoring and recording the axial and radial deformations of coal petrography samples in real time, directly and effectively measuring the DH4 permeability of the coal petrography before and after the fracture without unloading the coal petrography sample stress, and measuring the CH4 permeability of the coal petrography after the fracture under the action of creepage. The measurement methodis high in precision, intuitional and high in automation degree, and the device is simple in structure.

Description

technical field [0001] The invention relates to a coal rock supercritical carbon dioxide fracturing-creep-seepage test device under high temperature and high pressure. The fracturing medium is supercritical carbon dioxide, which belongs to the field of rock mechanics and engineering technology. Specifically related to deep coalbed methane mining, using supercritical carbon dioxide as a fracturing medium to fracture coal rock samples, real-time monitoring and recording of supercritical carbon dioxide temperature, pressure changes and fracture initiation and expansion during supercritical carbon dioxide fracturing characteristics, and simultaneously monitor and record the axial and radial deformation of the coal sample in real time, and measure the gas permeability of the coal sample before and after fracturing under the condition of not unloading the stress of the coal sample, and obtain the pressure The change rule of the permeability of the cracked coal rock sample under the ...

AI Technical Summary

Problems solved by technology

The existing true triaxial fracturing simulation test devices and methods can simulate hydraulic fracturing and other gas fracturing tests under the conditions of temperature and stress in deep buried formations, but it is difficult for true triaxial fracturing devices to directly measure the post-fracture Gas Permeability of Square Specimen

And for the existing triaxial fracturing device (cylindrical sample), such as CN 105510142 A, it is difficult to directly measure the permeability of the sample before and after fracturing accurately under the stress condition of not unloading the sample, and it is difficult to realize Under the conditions of high temperature (300°C) and high pressure (70MPa), acoustic emission technology is used to accurately and reliably monitor the crack initiation and expansion characteristics of the sample during the fracturing process, and to observe, analyze and grasp the formation and expansion of cracks mechanism

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