Underground coal seam hydrofracture crack oriented developing method

Abstract

The invention discloses an underground coal seam hydrofracture crack oriented developing method which comprises the following steps: (1) drilling into a hydrofracture drill hole and oriented drill holes, wherein the number of the hydrofracture drill hole is one, the oriented drill holes are arranged around the circumference circle at intervals, and respectively conducting water jet cutting to the hydrofracture drill hole and all oriented drill holes, wherein water jet cutting is achieved through a high-pressure water jet cutting device; (2) respectively conducting hole sealing to the hydrofracture drill hole and all oriented drill holes; and (3) conducting hydraulic fracturing to the hydrofracture drill hole. According to the underground coal seam hydrofracture crack oriented developing method, secondary disasters of a coal seam top base plate caused by disordered developing of cracks can be avoided, meanwhile, effective stress in the hydrofracture area can be reduced, closing of the cracks is retarded, flow conductivity of the cracks is strengthened, and therefore the purposes of effectively managing gas and efficiently pumping and exploiting the gas can be achieved.

Description

technical field [0001] The invention relates to a coal mine safety control method, in particular to a high-efficiency hydraulic fracturing method for strengthening gas drainage underground in a coal mine. Background technique [0002] "Hydraulization" as a high-efficiency gas drainage and gas disaster control technology has been widely promoted and applied in recent years, especially for the complex occurrence conditions of high ground stress, high gas pressure, and high gas content, "hydraulicization" technology has a wide range of applications prospect. Hydraulic fracturing has the advantages of a wide range of pressure relief and simple process operation, which greatly reduces the amount of drilling feet and improves efficiency. However, with the continuous increase of coal seam burial depth, the distribution of in-situ stress becomes more complicated, resulting in the continuous increase of crack initiation pressure and disorderly expansion of cracks, which will lead to...

AI Technical Summary

Problems solved by technology

For example, the patent publication number is: CN101581231, and the patent titled "Method for Gas Drainage of Loose Coal Body by Cracking Drilling Hydraulic Fracturing" uses drilling to loosen the coal body so that the cracks will always expand in the loose coal body. Due to the limitation of the diameter, it can only loosen the coal body in a small area nearby, so if the method is to be implemented smoothly, a large amount of drilling work is still required

The patent publication number is: CN102071921A, and the patent titled "Drilling Downhole Drilling Pressure Integrated Segmented Fracturing Device and Gas Drainage Process" only focuses on the hydraulic fracturing process, without considering the expansion and closure of fractures

The patent publication number is: CN202023547U, the patent for the patent "pulsating hydraulic fracturing equipment for underground coal mines". The pulsating pressure generated by the pulsating water injection pump is used for fracturing, and the expansion and closure of cracks are also not considered.

Images