Coal rock hydraulic fracturing crack micro-seismic positioning and expansion mechanism monitoring method
A hydraulic fracturing and microseismic technology is used in the monitoring and evaluation of coal rock mass fracturing, the microseismic location of coal rock hydraulic fracturing cracks and the monitoring of the expansion mechanism. It can improve the integrity, avoid costs, and improve economic benefits.
Active Publication Date: 2021-06-29
CHINA UNIV OF MINING & TECH
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[0002] With the increase of the mining depth and intensity of coal resources, gas disasters, especially the dynamic disasters coupled with coal and gas, are becoming more and more serious; and although gas (coal bed methane) is a major source of danger underground, it is also a valuable clean energy ;Relief pressure and increase permeability of low-permeability coal seams, improve reservoir permeability and gas extraction rate are important ways to control deep gas disasters and efficiently develop and utilize gas resources; hydraulic fracturing is an important way for oil and shale gas resources The core technology developed has been widely used in the transformation of low-permeability reservoir permeability; in recent years, hydraulic fracturing technology has been relatively successful in coal mine underground coal seam pressure relief and permeability enhancement to prevent and control gas disasters and improve gas drainage efficiency. application; however, there has been no effective technical means for the monitoring of coal and rock hydraulic fracturing fractures in coal mines and the evaluation of fracturing effects, which seriously restricts the further development of coal and rock hydraulic fracturing theory, technology and applications; The elastic wave signal generated by rock mass rupture is used to monitor and evaluate the damage of coal and rock mass according to the source location results; at present, microseismic monitoring technology is mainly used for monitoring and early warning of mine rockburst, rockburst and other dynamic disasters; As a means of effective monitoring of coal and rock mass fracture, there are few studies and applications in the monitoring and evaluation of coal and rock mass hydraulic fracturing; while coal mine hydraulic fracturing of coal and rock mass is being performed, there are coal seam working faces near the fracturing area Mining, roadway excavation, blasting and other mining activities, hydraulic fracturing and the above-mentioned mining activities will cause damage and rupture of coal and rock mass, thereby inducing microseismic waveform signals; When the coal rock sample is damaged by the water pressure, its external load will also damage the coal rock sample and generate a microseismic waveform signal; if the monitored microseismic waveform signal is used directly without distinction, the hydraulic fracturing fracture shape and Monitoring the expansion process may cause a large deviation from the real hydraulic fracturing fractures; therefore, how to distinguish the microseismic signals induced by hydraulic fracturing and other activities such as mining, the microseismic positioning monitoring results of hydraulic fracturing fractures in coal and rock mass The authenticity and reliability are very important; in recent years, some scholars and field engineers have also begun to pay attention to the microseismic monitoring of coal and rock hydraulic fracturing, and proposed some hydraulic fracturing microseismic monitoring devices and methods, but the existing technology does not involve the above mentioned In fact, the location of sensors in the laboratory and field, accurate identification of effective microseismic events, high-precision arrival information and source location results will all affect the hydraulic pressure of coal and rock mass. The authenticity and reliability of cracks and microseisms; more importantly, the existing various fracturing monitoring methods mainly use the results of microseismic source location to monitor hydraulic fracturing, and rarely involve the simultaneous use of source location and focal mechanism inversion results to jointly characterize hydraulic fracturing. Spatiotemporal distribution and propagation mechanism of fracturing fractures
At present, these problems still exist and have not been well resolved
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[0056] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.
[0057] Such as Figure 1-6 As shown, this example provides a coal hydraulic fracturing fracture microseismic location and expansion mechanism monitoring method, which specifically includes the following steps:
[0058] (a) Determine the key areas to be monitored according to the operation site of coal and rock mass fracturing; according to the geometric shape of the underground roadway, the construction site environment and the nature of the rock mass, arrange...
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The invention discloses a coal rock hydraulic fracturing crack micro-seismic positioning and expansion mechanism monitoring method. The method comprises the following steps of firstly, arranging a micro-seismic sensor according to an actual situation, and acquiring an original waveform signal in a fracturing process; on this basis, providing an event screening window with an updatable length, scanning data of each channel by using a long and short time window method, and identifying effective micro-seismic events; screening out an effective micro-seismic event induced by hydraulic fracturing of coal and rock mass by defining a waveform sensitive value, then obtaining high-precision arrival time of the micro-seismic event by utilizing a local AIC method, calculating the position of a fracture source, and inverting a seismic source mechanism according to a P-wave amplitude and the initial movement information; and finally, combining micro-seismic positioning and seismic source mechanism information. The method is advantaged in that the spatial distribution form and the fracture mechanism of a hydraulic fracturing crack can be disclosed, the influence range of hydraulic fracturing of a coal seam is determined, and the method has instructive significance in real-time dynamic adjustment of parameters, determination of a fracturing radius and reservoir evaluation in the fracturing process.
Description
technical field [0001] The invention relates to a coal rock mass fracturing monitoring and evaluation method, in particular to a coal rock hydraulic fracturing fracture microseismic positioning and expansion mechanism monitoring method, which belongs to the technical field of rock mass fracturing and engineering geophysical monitoring. Background technique [0002] With the increase of the mining depth and intensity of coal resources, gas disasters, especially the dynamic disasters coupled with coal and gas, are becoming more and more serious; and although gas (coal bed methane) is a major source of danger underground, it is also a valuable clean energy ;Relief pressure and increase permeability of low-permeability coal seams, improve reservoir permeability and gas extraction rate are important ways to control deep gas disasters and efficiently develop and utilize gas resources; hydraulic fracturing is an important way for oil and shale gas resources The core technology deve...
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Login to View More IPC IPC(8): G01V1/28G01V1/30
CPCG01V1/288G01V1/306
Inventor李楠蔡超房柳林陈鹏秦艳丽王承淳温耀林刘鹏张园惠
OwnerCHINA UNIV OF MINING & TECH