CN114687676A - Reverse embedding device for drilling hole in surrounding rock - Google Patents

Abstract

A reverse embedded device for drilling a surrounding rock, and high-pressure water fracturing of a rock stratum are indispensable technical means for exploiting underground fluid energy. The key technique for fracturing a formation is lock-fracturing. The invention relates to a physical mechanical device, which comprises a connector, a base and a support column body, wherein the support column body comprises a column base, a foot tip and the like in a geometric shape. During operation, the hole is positively inserted, and the surrounding rock is reversely embedded behind the hole. High-pressure water injection is used as a power source, and the high-pressure water injection is reversely embedded into a rock mass according to the conversion rule of plumpness pressure difference. If necessary, a locking seal ring can be added at the lower end part of the device.

Description

Reverse embedding device for drilling hole in surrounding rock

Technical Field

The invention discloses a reverse embedding device for drilling surrounding rocks, relates to an underground coal mine high-pressure water fracturing rock stratum for efficiently extracting coal bed gas, preventing rock burst, coal and gas outburst and other accidents, and relates to the exploitation of underground new energy resources such as high-heat rocks and the support of underground engineering such as tunnels.

Background

The conventional gas drainage is called as gas drainage for extracting coal bed gas under a coal mine. The problem to be solved is mainly to prevent gas accidents, especially malignant accidents such as coal and gas outbursts. The invention solves the problem that the gas accident is prevented and the development and utilization of the coal bed gas are also great things from the perspective of clean energy coal bed gas. It must be recognized that for most mines, the use of gas (coal bed gas) is still at a low stage. The 'gas drainage' is to be discharged by extraction and directly discharged into the atmosphere. Not only wastes resources, but also has the greenhouse effect which is 21 times that of carbon dioxide, and the damage to the ecological environment is strong. From the perspective of clean energy, the calorific value of 1 cubic meter of pure coal bed gas is equivalent to 1.13 kg of gasoline and 1.21 kg of standard coal, and no waste gas is generated by combustion of the coal bed gas. The heat value is 3-4 times higher than that of general coal. From the perspective of coal mine safety, the extraction rate is improved by 20%, and the gas accident rate can be reduced by 70% -85%.

China is the largest coal producing and consuming country in the world and has the largest number of underground coal mines in the world. The gas (coal bed gas) extraction from the underground coal mine is good, particularly for a high gas mine, the occurrence of serious accidents such as coal and gas outburst can be avoided, the utilization rate of clean energy can be improved, the pollution to the environment is reduced, and the carbon peak reaching and carbon neutralization are contributed.

The gas content in the coal bed is not equal to the extraction concentration. The gas is mainly adsorbed on the surface of the coal matrix particles. By adopting the high-pressure water fracturing technology, the air permeability of the coal body can be obviously improved, and the extraction concentration is obviously improved.

The technical means of fracturing the rock coal bed by high-pressure water is an indispensable technical means for exploiting coal bed gas on the ground. In this respect, the technical level of China is far from the advanced level of China. The conventional means for solving the problem of permeability of coal mine underground coal strata is the means of gunpowder explosion, which is not preferable because of safety risk. Fracturing a poorly permeable rock mass with high pressure water is an effective means to be taken.

The lock-pressure technology is the core technology of high-pressure water fracturing rock stratum. The technology for solving the problem of breakthrough in the underground mine for many years has not been available. Different from the construction by the ground and the machinery, the underground coal mine is required to be drilled, blocked and locked manually. The diameter of the holes, whether bedding holes (coal holes) or through-layer holes (rock holes), is generally 75mm-133mm, and the depth of the holes is 50-100M, but not the depths of kilometers and more than the ground. Moreover, geological damage and water pollution caused by surface mining are well known. The single-hole fracturing mode adopted in the underground coal mine cannot cause the natural environment to exceed the original influence range of the mine, and the negative influence of the hydraulic fracturing technology can be ignored.

The key to fracturing the rock formation with high pressure water is lock pressure. The key defects of the prior art are that the support of a physical mechanical technical means is lacking, for example, a mining hole packer has the defects that the requirement on the hole forming condition of a drilling hole is extremely high, rubber in the hole packer cannot enter cracks of the surrounding drilling hole wall after expanding, the ventilation of a circumferential seam is caused, the pressure of high-pressure water cannot be borne only by the friction force generated by the expansion force of the rubber and the drilling hole wall, the cost is high, other mechanical equipment is required for assistance, and the hole packer cannot be recycled. To lock up hydrostatic pressures of 20 mpa and above, whatever the material used for plugging, even those materials with comparable swelling and adhesion properties are far from adequate solutions. The invention overcomes the defects in the prior art, and adopts components with strong pressure resistance and stable structure, thereby thoroughly solving the problems.

Disclosure of Invention

The method for solving the technical problem of poor air permeability of the coal rock mass of the high-gas coal mine by adopting high-pressure water fracturing fails to achieve a satisfactory effect for a long time. The main industry of coal mines is coal mining, and the underground environment is not suitable for transplanting the fracturing mode of the above-ground mining fluid energy into the underground coal mine. The explosive cracking method has a great potential safety hazard. The key to fracturing is lock fracturing. The limited expandability of the seal or/and the limited adhesion is far from sufficient to resist the hydrostatic pressure of 20-30 mpa. In consideration of coal mine safety, clean energy utilization and environmental protection, the inventor develops the reverse insert for the drilling of the surrounding rock according to the principle of physical mechanics and years of practical experience.

The reverse embedded device for the wall rock drilling is characterized in that: one end of the special pipe connector is a pipe hoop head, the other end of the special pipe connector is a pipe connecting seat, and the special pipe connector and the pipe hoop head are integrated. The transverse dimension of the pipe connecting seat is larger than that of the pipe hoop head. The pipe hoop head is only used for connecting a water injection pipe. The water injection pipe and the extraction pipe are used for two purposes. After the water injection fracturing is completed, the water injection pipe is converted into a drainage pipe in the drainage stage. The pure gas drainage pipe usually uses a plastic pipe, and the water injection pipe needs to use a steel pipe.

The mechanism of the present invention is primarily focused on the nozzle block. At least three support columns are elastically connected at the bottom of the connecting pipe seat and the arc-shaped edge, and when the insert is inserted into the hole, the support columns are inwards folded due to the constraint of the drilling hole. After the hole is drilled, the pedestal touches the wall of the drilled hole. The pipe connecting seats at the upper ends of the supporting columns are respectively provided with a groove so as to control the reasonable angle of the supporting columns. Typically, the mast elevation does not exceed 45 °. On the one hand, the angle of the support column is limited not to exceed the reasonable application range, and on the other hand, the support column is suitable for different hole diameters in a certain range. The hole diameter is usually determined by the size of the drill bit, and the drill bits of the same size can produce different drill holes due to different properties of the surrounding rock. The lower end of the column body is a column foot. The end of the column foot is a foot front. The foot front has a relatively sharp geometric feature. After the hole is drilled, even under the static condition, the shallow layer surface can be embedded into the surrounding rock under the action of micro elasticity, and at least a specific limit of the surrounding rock drilling hole can be stabilized.

Due to the need for the access hole, the diameter of the insert nozzle must be smaller than the diameter of the drilled hole, and therefore a wider or narrower circumferential seam must be present between the two. Due to the reasons of poor hole forming quality and the like, when the annular seam is too wide, water can run out towards the direction of the drilling hole through the annular seam in the water injection process. Not only water is consumed, the water injection time is prolonged, but also the effect of fracturing the rock stratum can not be achieved. In view of this, the invention designs a rubber lock pressing ring. The lock pressing ring is horn-shaped and is sleeved on the water injection pipe section below the bottom of the embedder adapter, and the upper end of the lock pressing ring is fixed by a tightening device.

Along with the gradual increase of water pressure, the water pressure acts on the embedding device, and the rubber lock pressing ring is unfolded outwards from bottom to top while the support is embedded into the wall of the drilled hole, so that the circular seam between the wall of the drilled hole and the connecting pipe seat of the embedding device is covered. Of course, there are other technical means for solving the problem of the circular seam, which are described in the section of the detailed description.

Description on 'reverse embedding'. The inlet hole direction is forward direction, and the outlet hole direction is reverse direction or reverse direction. The reverse embedding device for the wall rock drilling hole disclosed by the invention is used for positively entering the hole, which is undoubtedly not surprising. The key is how to 'embed it backwards'. High-pressure water injection is used as a power source, according to the Newton's third law and following the change rule of flow (flow) saturation pressure difference, the stress surface of the invention is combined with column base and foot peak in geometric shape to cause stress concentration, and the embedding device can be reversely embedded into the rock mass.

When high pressure water enters the borehole through the water injection pipe, the water still flows in the borehole. During the transition to the saturated state, the pressure will gradually increase. The invention utilizes the law of flow pressure maintaining difference to gradually increase the pressure acting on the reverse embedder interface.

The insert is not completely closed at this point because its crimped rubber seal is not fully deployed. An annular seam is also present between the sealing ring and the bore hole wall. Along with the increase of water pressure again, the embedding device is pressed, the locking sealing ring is gradually unfolded, and the annular seam is sealed by the locking sealing ring.

For coal holes (bedding holes), the fracture occurs when the hydrostatic pressure reaches 20 mpa, and for rock holes (through-bedding holes), the hydrostatic pressure is required to be above 20 mpa. And judging whether the rock mass is fractured or not, wherein one is to see whether the pumping pressure is suddenly reduced or not, and the other is to see whether water is discharged from the upper part of the drilling hole or not. However, this condition is often seen as an artifact, which can cause false positives. Finally, the judgment is carried out according to the gas extraction concentration. This artifact is due to insufficient plug depth and not true lock-up to the solid coal formation. Thus, the plugs are installed as deep as possible down hole (coal hole), for example ten meters, fifteen meters, or more. The cross-bore (rock bore) is encountered across the rock formation. Moreover, the structure of the embedding device is beneficial to deep plugging and pressure locking. According to the properties and conditions of the surrounding rock, the product can resist the hydrostatic pressure of 30 MPa by using one hole drilling reverse embedding device.

Besides using high-pressure water injection as a power source to reversely embed the inserter into the drilling surrounding rock, other technical means can be used to reversely embed the inserter into the drilling surrounding rock. Similarly, the reverse insert must be inserted into the hole in a forward direction, and after reaching the specified section of the borehole, the self-elasticity of the insert post and its foot, and the geometry of its foot tip, cause stress concentrations. The extraction pipe is pulled outwards by adopting physical and mechanical tension at the drilling hole, and the reverse embedment device is naturally embedded into the surrounding rock of the drilling hole in a reverse way as the reverse embedment device is firmly combined with bearing media such as a steel pipe or an anchor cable.

The multifunctional characteristics and beneficial effects of the product.

The product has the following multifunctional characteristics. 1) The whole system of the drilling surrounding rock is firmly combined into a whole by the embedded device, the water injection pipe (the drainage pipe) and the drilling surrounding rock, the stability is favorable for multiple times of drainage, and the drainage standard of 'drainage when drainage is performed' is embodied. 2) The embedding device is also a stopper, and the sealing effect of the embedding device exceeds that of different types of sealing bodies in the prior art. 3) In the drilling, can play the effect of taking out and putting a tub centralizer, make and take out and put the pipe and be in drilling central part, be favorable to this product and other seals the cooperation application of body. 4) The product is suitable for surrounding rock drilling bare holes and is also suitable for sleeves in the surrounding rock drilling.

The present invention achieves the following advantageous effects. The reverse embedded device for the wall rock drill hole is applied to high-pressure water fracturing rock formations of coal mine underground gas drill holes, and 1) the gas extraction concentration can be improved by 20-30%; 2) the gas accident rate can be correspondingly reduced by 85 percent; 3) the utilization rate of the gas as the coal bed gas is undoubtedly obviously improved, so that the gas emission is greatly reduced, and the pollution to the environment is reduced. 4) By adopting the fracturing method, the punching number can be reduced by one third due to the expansion of the punching interval; 5) except for pumping, no energy is consumed; 6) compared with the existing non-fracturing drainage mode, the cost is not increased or decreased, and the cost can be saved by more than 50% only by one material cost.

Drawings

FIG. 1: and a longitudinal state reverse embedder. Pipe hoop head, pipe hoop seat, prop stand, prop foot, foot tip and groove

FIG. 2: the reverse insert traverses into the hole. Drilling hole eight water injection pipe (drawing pipe)

FIG. 3: and the reverse embedder column base is embedded into the surrounding rock.

Detailed Description

In short, the water injection pipe (extraction pipe) is connected to the two ends of the inserter, and the inserter is conveyed into the drill hole to a set depth as shown in fig. 2 (eight), so that the water injection can be carried out. In addition, the implementation method is adjusted according to specific conditions, including conditions of the field, rock mass conditions, drilling conditions, engineering requirements, water injection pump pressure and the like. For example, the present embedder may be used singly, or may be used in combination of one or more than one. When more than one is used, the spacing and the fixed-point surrounding rock conditions are reasonably arranged. May be used in conjunction with other plugging materials or products. For example, other plugging materials or products may engage the bottom of the insert or may be interposed between two inserts. This may replace the function of the rubber seal described in the summary of the invention section. In short, creative labor is not needed, and on the basis of the invention, certain flexible implementation room can be provided according to actual conditions and actual problems needing to be solved.

Claims (2)

1. A reverse embedding device for drilling hole in surrounding rock is characterized by that it is a special-shaped pipe connector, one end of which is a pipe hoop head, and the other end is a pipe connecting seat, and they are integrated into one body. At least three elastic pillars are axially connected to the bottom of the connecting tube seat, the bottom of the pillar body is a pillar base, and the end part of the pillar base is a geometrical foot front.

2. The reverse wall rock borehole embedment of claim 1, wherein the socket seats at the upper ends of the support posts each have a recess for controlling the proper angle of the support posts.

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