A method for controlling fracturing by segmental and direction-controlled rockburst on hard roof

Abstract

The invention discloses a method for controlling rock burst of a hard roof by segmented direction-controlled fracturing, comprising the following steps: S10, acquiring ground stress parameters of a hard roof; S20, designing the layout of directional long boreholes and the parameters of the direction-controlled fracturing technology ; S30, construction of directional long borehole; S40, installation of segmental control fracturing device in directional long borehole; S50, segmental control fracturing construction; S51, formation of artificially prefabricated control jet fracture; Fracture and fracture network; S53, stop the pump, drain water, packer shrinks, and drag to the next fracturing position; S54, repeat the steps of S51-S53 to complete the entire directional long drilling fracturing construction; the hard The segmented and controlled fracturing treatment method of roof impact rock pressure accurately controls the level of the hard roof, and performs fracturing segment by segment to form a three-dimensional fracture communication network, which effectively weakens the hard roof and promotes the hard roof to collapse in a timely manner.

Description

technical field [0001] The invention belongs to the technical field of underground safety in coal mines, in particular to the technical field of rock burst disaster treatment caused by hard roofs of coal seams, and specifically relates to a method for treating rock bursts of hard roofs by segmented and controlled fracturing. Background technique [0002] According to statistics, nearly 1 / 3 of the coal seams in China have hard roofs and are widely distributed. The hard roof above the coal seam is mainly a rock formation with stable thickness, high strength, good integrity, and hard to collapse. Its stable mechanical properties and support structure of the working face lead to a large area of ​​roof overhang. With the continuous advancement of the working face, when the roof is difficult to support, the suspended roof suddenly collapses, causing a large area of ​​pressure in the stope, and under the action of the large caving step of the thick and hard rock formation, the pres...

AI Technical Summary

Problems solved by technology

However, in the treatment of hard roofs by existing hydraulic fracturing technology, artificial prefabrication is difficult to control the direction of injection fractures, the scale of fracture development is limited, and the weakening effect is difficult to guarantee

Moreover, during the conventional drilling construction process, the drilling precision is low, and it is easy to deviate from the treatment target layer, resulting in poor fracturing weakening effect, and it is difficult to eliminate or reduce the strong mine pressure problem caused by the hard roof; when the drilling precision is low and the fracturing Weakening the roof strata in non-target layers can easily cause roof caving or leaking, which restricts mine safety production

Conventional fracturing treatment of hard roof technology has a large overall construction volume, small effective pressure relief area, blind spots and blind sections, it is difficult to form a three-dimensional effective fracture network system, and cannot fully release hard rock formations and recovery dynamic pressure energy to achieve full pressure relief put the top

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