CN108301807A - Hole wall fixing device for gas extraction drill hole of soft coal seam and construction method - Google Patents

Abstract

The invention belongs to the technical field of coal mine safety, and relates to a hole wall fixing device and a construction method for gas drainage drilling in soft coal seams, including a hollow drill rod for inserting into the coal seam, a drill bit installed at the front end of the drill rod, and the drill rod. A hole sealer is set in the middle and rear part, the hole sealer is connected with a hole sealer grouting pipe, the rear end of the drill pipe is equipped with a high-pressure rotating water tail connected with the drill pipe, and a high-pressure rubber hose is connected to the high-pressure rotating water tail. A reinforcement liquid is placed in it, and when the reinforcement liquid penetrates into the cracks smaller than 0.1mm and narrower in the coal seam, it will solidify immediately. The base additive is 0.9-1.1%, and the sodium silicate is 9-11%, which solves the problem of serious hole collapse in the drilling process of soft coal seam gas drainage in the prior art.

Description

Hole wall fixing device and construction method for gas drainage drilling in soft coal seam

technical field

The invention belongs to the technical field of coal mine safety, and relates to a hole wall fixing device and a construction method for gas drainage boreholes in soft coal seams.

Background technique

More than 95% of high-gas and outburst mines in my country belong to low-permeability coal seams, with soft coal and high gas content. Various types of long-distance horizontal drilling underground for gas drainage play an important role in mine disaster prevention, gas resource development and utilization, and environmental protection. Reasonable and efficient gas drainage can greatly solve the problem of mine safety production and alleviate the tense situation of energy supply and demand . Affected by poor drilling stability factors, it is difficult to control gas in soft and high-gas coal seams. Therefore, it is particularly important to study methods for controlling drilling instability in soft coal seams. Currently, there are two types of methods: hole wall stabilization technology during drilling and hole formation technology. The latest hole wall stabilization technology. The hole wall stabilization technology after hole formation can also take into account the hole wall stability during drilling. The current development status and brief schemes of hole wall stabilization technology after hole formation are mainly as follows:

Insert the screen pipe protection hole into the borehole that has been formed. The earliest domestic test is the Shenyang Coal Industry Xima Coal Mine imitating the heart bypass surgery method in the medical field, that is, after the hole is formed, the screen pipe is manually sent into the hole. In the stage of sending the pipe into the hole, there are big problems, mainly because most of the hole wall is incomplete, and the pipe is easy to get stuck. Generally, it cannot be sent in after 20m, and the effect is not ideal (Xu Qingwu, Wang Guojun, Dong Li, etc. Gas pumping Discussion on Hole Protection Technology. Coal Mine Safety, 2007 (1) 39-40). The disadvantage of this method is that the pipe is often stuck in the process of feeding into the borehole, and the maximum feeding is 20m. Even if the guide wheel is added to the front end of the pipe, the maximum feeding is only 50m. Moreover, the construction is difficult and the cost is high, and it cannot be reached after sealing the hole. expected result.

The Xi'an Research Institute of the General Academy of Coal Science Research has developed a wind pressure air drilling technology and supporting equipment in soft and outburst coal seams. That is to say, when the drill bit is drilled from the opening to the final hole, it will not start drilling first, and will be sent into the hole protection screen through the inner hole of the drill pipe, and then the drill will be pulled out. The hole protection screen is left in the hole through the core openable drill bit. Field tests of this technology have been carried out in mining areas such as Huaibei and Huainan (Yin Xinsheng, Fan Dong, Yao Ke, etc. Wind pressure air drilling technology and supporting equipment in soft and outburst coal seams. Coal Science and Technology. 2009 (09) 72-74). Although this method can send the screen pipe to the bottom of the hole, because the pipe is lowered from the inside of the drill pipe, the number of screen holes with a smaller pipe diameter is limited, and the drainage effect is not ideal.

The Hunan Coal Science Research Institute has developed a drag-type casing running method and device, that is, the casing follows the hole-forming method in the severe injection hole area. After the drill pipe is drilled due to serious blowout holes and cannot continue drilling, the drill pipe is returned, changed to the variable diameter drill bit and casing at the hole opening, and the drill pipe and casing are directly fed into the borehole manually to the hole Bottom stop. Re-introduce the drilling rig, continue to drill at a slow speed and evenly, the casing is dragged inward by the drill bit through the upper ratchet of the casing of the drill pipe, and the casing is dragged and installed on the spray hole to protect the hole. After drilling the casing to protect the hole, the drill pipe is retracted, the ratchet is reset, and the casing is left. Theoretically, the drill bit can continue to drill deeper. After the wall protection of the injection hole section with severe drilling is completed, the special variable-diameter drill bit is narrowed and then passed through the casing and the drill pipe to exit the drilling hole, and the casing remains in the hole to continue to protect the wall (Zhou Songyuan, Zhao Jun, Liu Xuefu, etc. Serious Research on Hole Forming Technology and Equipment of Nozzle in Soft Coal Seam. Journal of Hunan University of Science and Technology (Natural Science Edition) 2011(04)11-16). This method has complex on-site process and cumbersome operation, and does not have practical promotion value.

Lu Yiyu et al. disclose a drill bit, a hole cleaning device and a hole cleaning method for underground gas drainage holes in coal mines. In this method, water jets are used to crush the accumulated coal body into particles in the collapsed hole section, and then the particles are taken away by jet high-pressure water flow, and then the gas drainage screen is synchronously lowered in the collapsed hole section (Lu Yiyu, Tang Jiren, Zhang Xinwei, etc. A drill bit, a hole cleaning device and a hole cleaning method for underground gas drainage holes in coal mines, 2014). This method is hydraulic punching, which is likely to cause additional accidents such as large-area collapse and blockage, and does not have the value of promotion.

Lin Boquan, Yao Xiangrong, Jiang Chenglin, and Zhai Cheng successively tested the technology of grouting the borehole wall to strengthen the borehole wall. A certain pressure of grout or curing agent is injected into the borehole, and its own pressure penetrates into the cracks around the borehole. Improve the mechanical strength of the drilling surrounding rock (Yao Xiangrong, Shi Biming, Wang Yongbao, etc. Gas drainage drilling and grouting hole forming technology in deep weak structure coal rock, Coal Science and Technology, 2010 (06) 67-70). The grouting pressure of this method is small, the grout penetration depth is not enough, it is not easy to form a stable hole wall, and it needs to be successfully grouted once after the hole is formed, and the hole collapse phenomenon in the drilling process cannot be well controlled. There are few studies on soft and high gassy coal seams in foreign countries, and the method of inserting screen pipes into boreholes is mainly used to control hole collapse.

The invention can solve the technical problem of the stability of the hole wall after the drainage borehole is formed. If the hole collapses seriously during the drilling process, the measures of segmental reinforcement can be taken. For the drainage borehole and gas content measurement by adopting hydraulic anti-permeability measures Drilling, gas pressure measurement drilling, etc., which are difficult to form holes, can be effectively solved.

Contents of the invention

In view of this, the present invention provides a hole wall fixing device and construction method for gas drainage drilling in soft coal seams in order to solve the problem of serious hole collapse in the drilling process of gas drainage in soft coal seams in the prior art.

In order to achieve the above object, the present invention provides a hole wall fixing device for gas drainage drilling in underground soft coal seams in coal mines. There is a hole sealer on the lower sleeve, and the hole sealer is connected with the grouting pipe of the hole sealer. The rear end of the drill pipe is equipped with a high-pressure rotary water tail connected to the drill pipe. A high-pressure rubber hose is connected to the high-pressure rotary water tail. There is a reinforcement liquid, which solidifies immediately when it penetrates into the cracks smaller than 0.1mm and narrower in the coal seam. The reinforcement liquid is a mixture of ash and water in a ratio of 1:1, and the ash is composed of 85-90% of cement and aluminum-based additives. 0.9-1.1%, sodium silicate 9-11%.

Further, a booster pump is installed on the grouting pipe of the hole sealer and the high-pressure rotary water tail.

Further, the aluminum-based additive acts as an expansion agent and is any one of three substances: calcium oxide, calcium sulfoaluminate and calcium oxide-calcium sulfoaluminate.

Further, the front end of the drill bit is uniformly provided with a number of spray holes.

A construction method for a hole wall fixing device for gas drainage boreholes in soft coal seams, comprising the following steps:

A. For the coal seam that needs to be drilled, use a larger diameter drill bit to drill into the coal seam for 10m, then withdraw the drill bit of this diameter, and replace it with a drill bit that meets the designed drilling diameter for drilling. The 10m large diameter drilling section at the hole is used Install the hole sealer, and install the hole sealer immediately at the middle and rear of the drill pipe when the hole is drilled to the design depth;

B. Turn on the booster pump on the grouting pipe of the hole sealer, and inject 6-8MPa water into the hole sealer through the hole sealer grouting pipe connected to the hole sealer to seal the hole;

C. After all the orifices are closed, turn on the booster pump on the high-pressure rotary water tail, and inject reinforcement liquid into the hole through the high-pressure rotary water tail and high-pressure rubber hose at the end of the drill pipe. The injection pressure of the reinforcement liquid is 3 to 5 MPa. After the injection flow tends to zero and stabilizes for 5 to 10 minutes, remove the pressure from the hole sealer;

D. After the hole sealer is removed, clean water is injected into the hole to flush the reinforcement liquid in the drill pipe and the reinforcement liquid in the drill hole;

E. After the drilling reinforcement is completed, follow-up operations such as hydraulic permeability enhancement measures or pressure measurement and content measurement can be carried out.

Further, the hole sealer and the drill pipe are of split structure, and the hole sealer does not affect the construction of the drill bit on the drill pipe.

Further, the same boosting pump is used for pressurizing the water in the hole sealing device and the reinforcing liquid in the high-pressure rubber hose.

Further, this construction method is suitable for multi-stage reinforcement in the process of coal seam gas drilling, that is, after the completion of step D, the reinforcement of the first stage of drilling is completed, and after the completion of the first stage of drilling reinforcement, repeat steps A to step D Until the drilling reaches the design depth, follow-up operations such as hydraulic permeability enhancement measures or pressure measurement and content measurement can be carried out.

The beneficial effects of the present invention are:

1. In the hole wall fixing device for gas drainage drilling in soft coal seams disclosed by the present invention, the drill bit and the drill pipe are threadedly connected, and the 8-10m part of the hole is reamed with a reaming drill so that the hole sealer can enter , the hole sealer is set on the drill pipe; when the drilling is completed, the hole sealer is set on the drill pipe at the hole part, and the water of 8MPa pressure is injected into the hole sealer through the hole sealer grouting pipe to seal the drill The orifice of the hole is sealed, and then the reinforcement liquid is injected into the hole through the high-pressure rubber hose and the high-pressure rotating water tail. The pressure of the reinforcement liquid is 5Mpa, and the drill hole is fixed by the reinforcement liquid. The reinforcement liquid is a liquid that does not solidify in containers of non-coal materials such as steel or rubber, but solidifies instantaneously in cracks of 0.1 mm or smaller in coal seams. The reinforcement liquid can be injected into the drill hole to form a hole After drilling, the wall of the hole is stable to prevent the phenomenon of hole collapse after drilling, and the deployment method of the reinforcement liquid is simple, has strong applicability, and is suitable for widespread promotion.

2. The construction method of the hole wall fixing device for gas drainage boreholes in soft coal seams disclosed by the present invention can solve the technical problem of the stability of the hole walls after the drainage boreholes are formed. If the hole collapses seriously during the drilling process, it can be Take step-by-step reinforcement measures. It makes it possible to effectively solve the situation that it is difficult to form holes, such as hydraulic anti-permeability measures, such as drainage boreholes, gas content measurement boreholes, and gas pressure measurement boreholes.

3. The construction method of the hole wall fixing device for gas drainage drilling in soft coal seams disclosed by the present invention effectively solves the existing problems in the prior art, such as construction difficulties, complicated process, failure to achieve expected results, additional accidents, The hole wall stabilization effect is poor and it cannot be segmented and consolidated at any time.

Description of drawings

In order to make the purpose, technical scheme and beneficial effect of the present invention clearer, the present invention provides the following drawings for illustration:

Fig. 1 is a schematic structural view of the hole wall fixing device of the present invention used for gas drainage boreholes in soft coal seams in underground coal mines.

Detailed ways

The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The reference signs in the accompanying drawings of the specification include:

Coal seam 1, drill bit 2, drill pipe 3, hole sealer 4, hole sealer grouting pipe 5, high-pressure rotary water tail 6, high-pressure rubber hose 7.

As shown in Figure 1, the hole wall fixing device for gas drainage drilling in soft coal seams under coal mines includes a hollow drill rod 3 for inserting into the coal seam 1 and a drill bit 2 installed at the front end of the drill rod 3, and the drill bit 2 and the drill rod 3. Thread connection is adopted, and the 8-10m part of the hole is reamed with the reaming drill bit 2, so that the hole sealer 4 at the middle and rear of the drill pipe 3 can enter the drill hole, and the pressure of 5MPa is enough to remove the residual reinforcement liquid in the hole of the drill bit 2. pressed into the coal body. The middle rear portion of the drill pipe 3 is covered with a hole sealer 4, the hole sealer 4 and the drill pipe 3 are of split structure, and the hole sealer 4 does not affect the construction of the drill bit 2 on the drill pipe 3. The hole sealer 4 is connected with the grouting pipe of the hole sealer 4 with a pressurized pump, and the rear end of the drill pipe 3 is equipped with a high-pressure rotary water tail 6 with a pressurized pump connected to the drill pipe 3, and the high-pressure rotary water tail 6 is connected There is a high-pressure rubber hose 7, and a reinforcement liquid is placed in the high-pressure rubber hose 7. The reinforcement liquid is a kind of container that does not solidify in steel or rubber and other non-coal materials, but occurs instantaneously in cracks of 0.1mm level or smaller in the coal seam 1. The solidified liquid and the reinforcing liquid are ash and water mixed in a ratio of 1:1, wherein the ash consists of 85-90% of cement, 0.9-1.1% of aluminum-based additives, and 9-11% of sodium water glass.

Example 1

One-time reinforcement after hole forming

A construction method for a hole wall fixing device for a gas drainage borehole in a soft coal seam, comprising the following steps:

A. Drill the coal seam 1 that needs to be drilled into the coal seam with a larger diameter drill bit 2 for 10m, then withdraw the drill bit 2 of this diameter, and replace it with a drill bit 2 that meets the designed drilling diameter for drilling. The large diameter of the hole section is 10m The drilling section is used to install the hole sealer 4, and when the drilling construction reaches the design depth, the hole sealer 4 is installed immediately at the middle and rear of the drill pipe 3;

B. Open the booster pump on the grouting pipe of the sealer 4, and inject 8 MPa water into the sealer 4 through the grouting pipe of the sealer 4 connected to the sealer 4 to seal the hole;

C. After all the orifices are closed, turn on the booster pump on the high-pressure rotary water tail 6, and inject reinforcement liquid into the hole through the high-pressure rotary water tail 6 and high-pressure rubber hose 7 at the end of the drill pipe 3. The injection pressure of the reinforcement liquid is 5 MPa. After the reinforcement liquid injection flow tends to zero and stabilizes for 5 to 10 minutes, the hole sealer 4 is depressurized and removed;

D. After the hole sealer 4 is removed, clean water is injected into the hole to flush the reinforcement liquid in the drill pipe 3 and the reinforcement liquid in the drill hole;

E. After the drilling reinforcement is completed, follow-up operations such as hydraulic permeability enhancement measures or pressure measurement and content measurement can be carried out.

Example 2

Multi-stage reinforcement in the process of hole formation

A construction method for a hole wall fixing device for a gas drainage borehole in a soft coal seam, comprising the following steps:

A. Drill the coal seam 1 that needs to be drilled into the coal seam with a larger diameter drill bit 2 for 10m, then withdraw the drill bit 2 of this diameter, and replace it with a drill bit 2 that meets the designed drilling diameter for drilling. The large diameter of the hole section is 10m The drilling section is used to install the hole sealer 4, and when the drilling construction reaches the design depth, the hole sealer 4 is installed immediately at the middle and rear of the drill pipe 3;

B. Open the booster pump on the grouting pipe of the sealer 4, and inject 8 MPa water into the sealer 4 through the grouting pipe of the sealer 4 connected to the sealer 4 to seal the hole;

C. After all the orifices are closed, turn on the booster pump on the high-pressure rotary water tail 6, and inject reinforcement liquid into the hole through the high-pressure rotary water tail 6 and high-pressure rubber hose 7 at the end of the drill pipe 3. The injection pressure of the reinforcement liquid is 5 MPa. After the reinforcement liquid injection flow tends to zero and stabilizes for 5 to 10 minutes, the hole sealer 4 is depressurized and removed;

D. After the hole sealer 4 is removed, clean water is injected into the hole to flush the reinforcement liquid in the drill pipe 3 and the reinforcement liquid in the drill hole;

E. After the first stage of drilling and reinforcement is completed, repeat steps A to D until the drilling reaches the design depth, and then follow-up operations such as hydraulic permeability enhancement measures or pressure measurement and content measurement can be carried out.

Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that it can be described in terms of form and Various changes may be made in the details without departing from the scope of the invention defined by the claims.

Claims (8)

1. The hole wall fixing device for gas drainage drilling in soft coal seams, which is characterized in that it includes a hollow drill rod for inserting into the coal seam and a drill bit installed at the front end of the drill rod, and the middle and rear parts of the drill rod are sleeved with sealing holes The hole sealer is connected with the hole sealer grouting pipe, and the rear end of the drill pipe is equipped with a high-pressure rotating tail connected to the drill pipe. The high-pressure rotating water tail is connected with a high-pressure rubber hose, and a reinforcement Liquid, when the reinforcement liquid penetrates into the cracks smaller than 0.1mm and narrower in the coal seam, it solidifies immediately. The reinforcement liquid is a mixture of ash and water in a ratio of 1:1, wherein the composition of ash is 85% to 90% of cement, aluminum Base additive 0.9-1.1%, sodium silicate 9-11%. 2. The hole wall fixing device for gas drainage drilling in soft coal seams according to claim 1, wherein a booster pump is installed on the grouting pipe of the hole sealer and the high-pressure rotating water tail. 3. The hole wall fixing device for gas drainage drilling in soft coal seams as claimed in claim 2, wherein the aluminum-based additive acts as an expansion agent and is calcium oxide, calcium sulfoaluminate and calcium oxide-sulfur Any one of the three substances of calcium aluminate. 4. The hole wall fixing device for gas drainage drilling in soft coal seams according to claim 3, characterized in that, the front end of the drill bit is evenly opened with a number of spray holes. 5. The construction method of the hole wall fixing device for gas drainage boreholes in soft coal seams based on any one of claims 1 to 4, characterized in that it comprises the following steps: A. For the coal seam that needs to be drilled, use a larger diameter drill bit to drill into the coal seam for 10m, then withdraw the drill bit of this diameter, and replace it with a drill bit that meets the designed drilling diameter for drilling. The 10m large diameter drilling section at the hole is used Install the hole sealer, and install the hole sealer immediately at the middle and rear of the drill pipe when the hole is drilled to the design depth; B. Turn on the booster pump on the grouting pipe of the hole sealer, and inject 6-8MPa water into the hole sealer through the hole sealer grouting pipe connected to the hole sealer to seal the hole; C. After all the orifices are closed, turn on the booster pump on the high-pressure rotary water tail, and inject reinforcement liquid into the hole through the high-pressure rotary water tail and high-pressure rubber hose at the end of the drill pipe. The injection pressure of the reinforcement liquid is 3 to 5 MPa. After the injection flow tends to zero and stabilizes for 5 to 10 minutes, remove the pressure from the hole sealer; D. After the hole sealer is removed, clean water is injected into the hole to flush the reinforcement liquid in the drill pipe and the reinforcement liquid in the drill hole; E. After the drilling reinforcement is completed, follow-up operations such as hydraulic permeability enhancement measures or pressure measurement and content measurement can be carried out. 6. The construction method of the hole wall fixing device for gas drainage drilling in soft coal seam as claimed in claim 5, characterized in that, the hole sealer and the drill pipe are split structures, and the hole sealer does not affect the drilling. Construction of drill bit on rod. 7. The construction method for the hole wall fixing device of the soft coal seam gas drainage borehole as claimed in claim 6, characterized in that, the water pressurization in the hole sealer and the reinforcement liquid pressurization in the high-pressure rubber hose adopt the same method. booster pump. 8. The construction method for the hole wall fixing device of the soft coal seam gas drainage borehole as claimed in claim 7, characterized in that, the construction method is suitable for segmenting multiple times in the drilling process of coal seam gas drainage drilling Reinforcement, that is, after the completion of step D, the reinforcement of the first stage of drilling is completed. After the first stage of drilling is reinforced, repeat steps A to D until the drilling reaches the design depth, then hydraulic anti-reflection measures or measurement can be carried out. Subsequent operations such as pressure measurement content.