The Research Status and Prospect of Guided Fracturing in the Field of Gas Prevention and Control

Yizheng He ； Wang Jian

《International Core Journal of Engineering》 8卷7期 (2022/07) Pp. 973-981

https://doi.org/10.6919/ICJE.202207_8(7).0129

摘要

In recent years, the country strongly promotes the management goal of ＂zero over-limit＂ of gas and ＂zero outburst＂ of coal seam. It is urgent to develop systematic, efficient and reliable pressure relief gas extraction technology to realize comprehensive utilization of gas energy and avoid the occurrence of gas disasters. With the mining of coal mines from shallow to deep, traditional gas extraction techniques based on the development of shallow coal seams are becoming more and more ＂unsuitable＂. Guided fracturing overcomes the disadvantages of conventional hydraulic fracturing technology of single fracture formed in the direction of maximum principal stress and ＂blank zone＂ of antireflection on both sides, and greatly improves the anti-reflection efficiency of coal seam. Currently, there are four main means to induce the expansion direction of hydraulic fractures, namely radial injection fracturing, control hole guiding, non-uniform pore pressure guiding and slotted compound hydraulic fracturing, can realize directional permeability enhancement of coal seam. Among them, the slotted compound hydraulic fracturing technology has the advantages of easy implementation and strong operability and controllability, and has a broad development prospect. Most of the current experimental studies on slotted compound hydraulic fracturing have focused on the direction of slit deviation angle, horizontal stress difference coefficient. In order to better develop and utilize this technology, we can start with the effective action range and applicable conditions of the slit length and spacing on the pressure crack in the soft seam with difficult seam formation and stable overburden roof; for improving the effective extension efficiency of fractured fractures in coal-rock complex formation, the formation mechanism of three-dimensional fracture network system of guided staged fracturing was studied and the evolution law of stress field in the process was explored, thus promote the wide application of hydraulic fracturing technology in coal mine disaster prevention.

關鍵字

Guided Fracturing ； Gas Prevention ； Coal Seam Permeability Enhancement ； Crack Extension

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