SU1719660A1 - Method of rock hydraulic fracturing - Google Patents

Abstract

The invention relates to the mining industry and can be used in the management of underground mining, for the decompression of a mountain range, for example, the administration of a hard-to-collapse roof. The goal is to reduce the complexity of directional hydraulic fracturing of rocks. The fracture well is drilled in the zone of increased tensile stresses of the roof rocks, which contribute to the directional propagation of hydraulic fractures. The lamination gaps are used as embryonic in fracturing. They provide directional crack propagation for a long distance. 3 hp f-ly, 4 ill.

Description

The invention relates to the mining industry and can be used to soften rock strata, mainly in the conduct of underground mining.

There is a method that includes drilling in the roof of the hole or hole, installing a sealer in the hole, and injecting pressure into the mountain range.

The disadvantage of this method is the high complexity of setting the direction of the fracture by cutting the pioneer gap in the slot walls.

Closest to the present invention is a method that includes drilling a well into the roof from a hole or hole, installing a sealer and injecting pressurized fluid into a rock mass.

This method also provides for pre-cutting the annular gap in the well. This operation is laborious, time consuming and use of equipment that is not commercially available.

The purpose of the invention is to reduce the complexity of directional hydraulic fracturing of rocks.

To this end, according to a known method, which includes drilling into the roof from the well development, installing a sealer in it and injecting fluid into the rocks under pressure, determine the position of the maximum tensile stress zone in the roof of the mine, drill a well perpendicular to the layers of the roof rocks up to the plane of contact of displaced rock layers, form additional cracks of the roof delamination

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by increasing the area of its undermining, and the injection of fluid is carried out after the beginning of the separation of the roof rocks.

In addition, the zone of maximum tensile stresses is determined by the magnitude of the deflection of the roof of the excavation, and the well is placed along the axis of symmetry of the transverse section of the deflection of the roof of the excavation.

In addition, the control of the formation of fracture splits is carried out through the well.

In addition, the area of underworking the roof is increased by cutting gaps in the sides of the mine.

Figure 1 shows the stratum of rocks in the area of the proposed hydraulic fracturing, section; figure 2 - section aa in figure 1; on fig.Z - the same as on figure 1 (in the presence of layers of rocks in the roof); figure 4 - the location of the sealer in the hole.

The method is carried out as follows.

In the development of coal seam 1, for example, production 2 is produced. Above production 2 in the roof 3, an area of tensile stress 4 is formed (stress diagram is shown). With the horizontal occurrence of formation 1, the maximum of this zone coincides with the vertical axis of the area of the production section 2. Of the generation 2, a hole is drilled or a well 5, which is located in the zone of maximum tensile stresses. Then, a sealer 6 is inserted into the well 5 until it stops and water is pumped out. At the same time, taking into account the effect of tensile stresses that contribute to the formation of a crack perpendicular to the axis of the borehole 5 and that water is injected into the disc-shaped gap 7 formed between the bottom of the borehole 5 by the sealer 6, the fracture fracture propagates parallel to the reservoir 1. In complex mining - geological situations, the position of the maximum of zone 4 of tensile stresses can be powerfully determined using instrumental methods and - computational methods.

Under the conditions of development of sedimentary deposits and with a slight tectonic disturbance, it can be argued that the position of the maximum tensile stress coincides with the vertical axis 8 of the symmetry of the deflection of the roof 9 3. From this, the location and direction of the well 5 can be determined after measuring the values of the deflection 9 roof 3 across the development of 2.

In order to increase the tensile stresses in the roof 3 and the formation of 10 cracks due to this, stratification that appears mainly at the contact of the rock layers increases the area of the underworking of the roof 3, for example, by cutting 2 slots 12 in the production boards.

or by drilling out coal or expanding production 2.

During the formation of a local part-time zone by cutting slits 12 in the well, sensors are installed to control

Rocks of the roof rocks 3, and after registering the beginning of the delamination, the sensors are removed, equip the mouth of the sealer 5 with a bis sealer using the injected fluid to initiate the development of the slit 10 over a large area.

It is advisable to place the bottom of the borehole 5 on the contact of the layers of the roof rock, where the probability of occurrence of the slit 10 of the delamination is high.

Then, in generation 2, a mechanized complex (not shown) is mounted and processing of the extraction column begins. The presence of a fracture in the roof eliminates its freezing, which reduces the dynamic loads on the clearing lining.

 Drilling a hydraulic fracture well to the zone of maximum tensile stresses ensures its intersection with a fracture 10, which contributes to the directional development of a hydraulic fracture, considering that

the crack 10 is always formed at the contact of the roof layers, then the drilling of the fracture well is carried out with their intersection, which provides hooking of the embryonic cracks 10. Water injection and massif after the formation of embryonic cracks of the roof splitting reduces the required water pressure, since the fracture occurs the weakest contact of the layers in

of the roof, high accuracy of fracture formation is ensured, since the embryonic fracture of the bundle has pointed edges.

The proposed method can be used in the management of a hard-breaking roof and for other technological purposes.

To implement the method, Taurus brand sealers can be used.

high-pressure installation UNR-0.2, providing a pressure of 30 MPa.

Claims (4)

Claim 1. A method of hydraulic fracturing of rocks, including drilling from a well in the wellbore, installing a sealer in it, and injecting a working fluid under pressure into the well, characterized in that, in order to reduce the labor intensity of directional hydraulic fracturing rocks, determine the position of the maximum tensile stress zone in the roof of the mine, drill a well perpendicular to the layers of roof rocks to the plane of contact of adjacent layers of rocks, form additional cracks of the roof delamination by increasing the area of its underworking, and injecting fluid after the beginning of the stratification of the roof rocks ..... 2. The method according to claim 1, whether or not, so that the zone of maximum stretching is 0. The stresses are determined by the amount of deflection of the roof of the excavation, and the well is placed along the axis of symmetry of the transverse section of the deflection of the roof of the excavation. 3. A method according to claim 1, wherein the monitoring of the formation of fractures is carried out through the well. 4. The method according to claim 1. This is due to the fact that the area of underworking of the roof is increased by cutting slits in the sides of the working. W ////// ШШ /////////, 1I 2 12 FIG L Aa fug.2