A drilling blowout prevention and gas extraction integrated hole sealing device and method

Abstract

The application discloses a drilling blowout prevention and gas extraction integrated hole sealing device and method, which comprises a sleeve, a tee joint, a gas extraction pipe and a surge bag. The integrated hole sealing device is installed at a control hole, at which time gas extraction operation can be performed on each control hole, and then hydraulic fracturing operation is continuously performed in a burst pressure hole. After one of the control holes is connected with a crack generated by the burst pressure hole, part of the gas and water-coal mixture will be discharged into the surge bag from the control hole. The surge bag is rapidly expanded from a folded state, thereby playing a buffering role. The control hole can extract gas, discharge water and discharge residue, the danger of a large amount of gas and water-coal mixture being suddenly discharged from the control hole is avoided, and whether each control hole is connected with the burst pressure hole can be known by observing the change of the surge bag. The control hole is temporarily blocked, thereby facilitating the continuous fracturing operation on other control holes, and finally all the control holes can be efficiently and accurately connected during the hydraulic fracturing process of the burst pressure hole.

Description

Technical Field

[0001] This invention relates to a sealing device and method, specifically an integrated sealing device and method for borehole blowout prevention and gas extraction, belonging to the field of mine gas disaster prevention and control technology. Background Technology

[0002] Gas disasters are the most significant threat to coal mine safety. As coal seams are mined at greater depths, problems such as high ground stress, low porosity, and poor permeability often arise, necessitating the use of methods such as water injection fracturing to increase coal seam permeability. Conventional hydraulic fracturing suffers from drawbacks such as high drilling workload, uneven fracturing, and poor permeability enhancement. A recently proposed "integrated blasting and injection" technology involves constructing control holes around the blasting borehole, followed by sequential blasting and hydraulic fracturing at the blasting borehole, connecting it to all control holes. This technology significantly reduces drilling workload, achieves more uniform fracturing, and improves permeability enhancement. However, during hydraulic fracturing, the control holes need to be sealed. Currently, most sealing and extraction methods still have certain shortcomings, which can be summarized as follows: First, they lack blowout prevention capabilities, easily leading to dynamic disasters such as gas eruptions, resulting in excessive gas levels and significant safety hazards; second, they cannot monitor the connection between the blasting borehole and adjacent control holes, thus failing to achieve efficient and precise connection between the blasting borehole and each control hole; third, the equipment used cannot simultaneously meet the needs of gas extraction and slag removal / drainage; fourth, they cannot achieve repeated fracturing of the coal seam between the blasting borehole and control holes. Therefore, providing a new sealing device and method that can effectively solve the above-mentioned technical problems is one of the research directions in this industry. Summary of the Invention

[0003] To address the problems existing in the prior art, the present invention provides an integrated borehole sealing device and method for borehole blowout prevention and gas extraction. It can not only monitor whether the blowout hole and the control hole are connected, but also act as a blowout prevention hole when they are connected, and can realize the integrated functions of borehole sealing, gas extraction and slag discharge and drainage.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: an integrated sealing device for drilling blowout prevention and gas extraction, comprising a casing, a tee, a gas extraction pipe and a blowout prevention bag;

[0005] The three ports of the tee are the first connection port, the second connection port, and the third connection port. One end of the sleeve extends into the control hole, and the other end of the sleeve is outside the control hole and is connected to the first connection port through the first quick connector. One end of the gas extraction pipe is connected to the second connection port through the second quick connector, and the other end of the gas extraction pipe is connected to the gas extraction system. The inlet of the anti-impact bag is connected to the third connection port through the third quick connector.

[0006] Furthermore, the anti-surge bag is made of a flexible material and is folded when not in use. If gas or a mixture of water and coal is ejected from the orifice, the anti-surge bag can quickly expand to provide cushioning.

[0007] The working method of the above-mentioned integrated borehole blowout prevention and gas extraction sealing device includes the following specific steps:

[0008] A. Construct blasting holes from the top of the roadway upwards to the target coal seam, and construct multiple control holes around the blasting holes. After hydraulically flushing one of the control holes, insert one end of the casing into the control hole and inject cement grout into the annular gap between the casing and the hole wall. After solidification, a cylindrical sealing section is formed.

[0009] B. Then, the integrated sealing device for blowout prevention and gas extraction is assembled outside the control hole with the sleeve. At this time, the blowout prevention bag is folded. Repeat the process of hydraulic flushing the control hole and installing the integrated sealing device for blowout prevention and gas extraction, so that each control hole is equipped with the integrated sealing device for blowout prevention and gas extraction.

[0010] C. Integrate the gas extraction pipes of each control hole into the coal mine gas extraction system for gas extraction operations. Since the inside of the tee is under negative pressure during the gas extraction operation, the anti-impact bag remains folded.

[0011] D. During gas extraction, hydraulic fracturing operations are continuously performed in the blast hole. After the blast hole fracture expands to one of the control holes, the blast hole is connected to the control hole. Some of the water, coal, and gas mixture generated by fracturing will be discharged from the control hole. The discharged mixture is discharged into the anti-surge bag after passing through a tee. The anti-surge bag starts to expand rapidly from a folded state. By observing the changes in the anti-surge bag, it can be determined that the control hole and the blast hole are connected. After the discharge of the water-coal mixture decreases, or after the anti-surge bag is filled to more than 80%, the hydraulic fracturing operation in the blast hole is stopped, the casing of the control hole is separated from the tee, and the casing of the control hole is temporarily sealed.

[0012] E. Then, hydraulic fracturing is performed again in the burst pressure hole, so that the fracture in the burst pressure hole continues to expand to other control holes. Observe the condition of the anti-impact bag corresponding to each control hole. If any anti-impact bag changes, repeat D to process the control hole. Repeat this process until the connection between all control holes and burst pressure holes is completed.

[0013] F. After completing the connection between all control holes and blast holes, open each blocked casing and connect the gas extraction pipe corresponding to each control hole to the casing, so as to continue the gas extraction operation for each control hole.

[0014] Furthermore, during the gas drainage operation in step F, when the gas drainage concentration is low, the gas drainage work is stopped, and the process of steps D and E is repeated for each control hole and blast hole, thereby realizing repeated fracturing of the coal body between the blast hole and the control hole, cleaning the coal slime between the pores, further promoting the development and expansion of the fractures, and ultimately improving the gas drainage effect.

[0015] Compared with existing technologies, this invention uses a combination of casing, tee, gas extraction pipe, and anti-blowout bag. After the construction of the blowout prevention and control holes is completed, the integrated sealing device for drilling blowout prevention and gas extraction of this invention is installed in the control holes. At this time, gas extraction operations can be carried out in each control hole, while hydraulic fracturing operations continue in the blowout holes. When one of the control holes connects with the fracture generated by the blowout hole, some gas and coal-water mixture will be discharged from the control hole into the anti-blowout bag. The anti-blowout bag rapidly expands from a folded state, playing a buffering role. This achieves gas extraction, water drainage, and slag removal in the control holes, avoiding a large amount of gas and water being released at the moment the control holes are opened. The sudden blowout of the coal mixture poses a danger. By observing changes in the anti-blowout bag, it is possible to determine whether each control hole is connected to the blowout hole. The control hole can be temporarily blocked, facilitating continued fracturing of other control holes. Ultimately, this achieves efficient and precise connection of all control holes during the hydraulic fracturing process of the blowout hole, allowing gas drainage operations to continue. Furthermore, when the gas drainage concentration is low, the above hydraulic fracturing, blowout prevention, and drainage and slag removal processes are repeated for each control hole and the blowout hole. This achieves repeated fracturing of the coal body between the blowout hole and the control holes, cleans the coal slime in the pores, further promotes fracture development and expansion, and ultimately improves the gas drainage effect. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0017] In the diagram: 1-Control hole, 2-Sleeve, 3-Cylindrical plugging section, 4-Tee, 5.1-First quick connector, 5.2-Second quick connector, 5.3-Third quick connector, 6-Gas extraction pipe, 7-Anti-rush bag. Detailed Implementation

[0018] The present invention will be further described below.

[0019] like Figure 1 As shown, an integrated sealing device for borehole blowout prevention and gas extraction includes a casing 2, a tee 4, a gas extraction pipe 6, and a blowout prevention bag 7.

[0020] The three ports of the tee 4 are the first connection port, the second connection port, and the third connection port. One end of the sleeve 2 extends into the control hole 1, and the other end of the sleeve 2 is outside the control hole 1 and is connected to the first connection port through the first quick connector 5.1. One end of the gas extraction pipe 6 is connected to the second connection port through the second quick connector 5.2, and the other end of the gas extraction pipe 6 is connected to the gas extraction system. The inlet of the anti-surge bag 7 is connected to the third connection port through the third quick connector 5.3. The anti-surge bag 7 is made of flexible material and is folded when not in use. Once gas is ejected from the hole and a water-coal mixture is discharged, the anti-surge bag 7 can quickly expand to provide a buffer. The first quick connector 5.1, the second quick connector 5.2, and the third quick connector 5.3 are all the same size. This arrangement allows the quick connectors to be compatible with each other, facilitating installation and use.

[0021] The working method of the above-mentioned integrated borehole blowout prevention and gas extraction sealing device includes the following specific steps:

[0022] A. Construct blasting holes from the top of the roadway upwards to the target coal seam, and construct multiple control holes around the blasting holes. After hydraulically flushing one of the control holes 1, insert one end of the casing 2 into the control hole 1, and inject cement slurry into the annular gap between the casing 2 and the hole wall. After solidification, a cylindrical sealing section 3 is formed.

[0023] B. Then, the integrated sealing device for blowout prevention and gas extraction is assembled outside the control hole 1 with the sleeve 2. At this time, the anti-blowout bag 7 is in a folded state. Repeat the process of hydraulic flushing of the control hole 1 and installing the integrated sealing device for blowout prevention and gas extraction, so that each control hole 1 is equipped with the integrated sealing device for blowout prevention and gas extraction.

[0024] C. All gas extraction pipes 6 of each control hole 1 are connected to the coal mine gas extraction system for gas extraction operation. Since the inside of the tee 4 is under negative pressure during the gas extraction operation, the anti-impact bag 7 is kept in a folded state.

[0025] D. During gas extraction, hydraulic fracturing is continuously performed in the blast hole. After the blast hole fracture expands to one of the control holes 1, the blast hole is connected to the control hole 1. Some of the water, coal, and gas mixture generated by fracturing will be discharged from the control hole 1. The discharged mixture is discharged into the anti-surge bag 7 after passing through the tee 4. The anti-surge bag 7 starts to expand rapidly from a folded state. By observing the changes in the anti-surge bag 7, it can be determined that the control hole 1 and the blast hole are connected. After the discharge of the water-coal mixture decreases, or after the anti-surge bag 7 is filled to more than 80%, the hydraulic fracturing operation in the blast hole is stopped, the casing 2 of the control hole 1 is separated from the tee 4, and the casing 2 of the control hole is temporarily sealed.

[0026] E. Then, hydraulic fracturing is performed again in the burst pressure hole, so that the fracture in the burst pressure hole continues to expand to other control holes 1. The condition of the anti-impact bag 7 corresponding to each control hole 1 is observed. If any anti-impact bag 7 changes, D is repeated to process that control hole 1. This process is repeated until the connection between all control holes 1 and burst pressure holes is completed.

[0027] F. After completing the connection between all control holes 1 and the pressure hole, open each of the sealed casings 2 and connect the gas extraction pipes 6 corresponding to each control hole 1 to the casings 2, so as to continue the gas extraction operation for each control hole 1.

[0028] Furthermore, during the gas extraction operation in step F, when the gas extraction concentration is low, the gas extraction work is stopped, and the processes of steps D and E are repeated for each control hole 1 and the blast hole, thereby realizing repeated fracturing of the coal body between the blast hole and the control hole 1, cleaning the coal slime between the pores, further promoting the development and expansion of the fractures, and ultimately improving the gas extraction effect.

[0029] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for operating an integrated borehole sealing device for blowout prevention and gas extraction, characterized in that, The integrated borehole sealing device for blowout prevention and gas extraction includes a casing, a tee, a gas extraction pipe, and a blowout-proof bag. The tee has three ports: a first connection port, a second connection port, and a third connection port. One end of the casing extends into the control hole, and the other end is outside the control hole and connected to the first connection port via a first quick connector. One end of the gas extraction pipe is connected to the second connection port via a second quick connector, and the other end is connected to the gas extraction system. The inlet of the blowout-proof bag is connected to the third connection port via a third quick connector. The specific steps are as follows: A. Construct blasting holes from the top of the roadway upwards to the target coal seam, and construct multiple control holes around the blasting holes. After hydraulically flushing one of the control holes, insert one end of the casing into the control hole and inject cement grout into the annular gap between the casing and the hole wall. After solidification, a cylindrical sealing section is formed. B. Then, the integrated sealing device for blowout prevention and gas extraction is assembled outside the control hole with the sleeve. At this time, the blowout prevention bag is folded. Repeat the process of hydraulic flushing the control hole and installing the integrated sealing device for blowout prevention and gas extraction, so that each control hole is equipped with the integrated sealing device for blowout prevention and gas extraction. C. Integrate the gas extraction pipes of each control hole into the coal mine gas extraction system for gas extraction operations. Since the inside of the tee is under negative pressure during the gas extraction operation, the anti-impact bag remains folded. D. During gas extraction, hydraulic fracturing operations are continuously performed in the blast hole. After the fracture in the blast hole expands to one of the control holes, the blast hole is connected to the control hole. Some of the water, coal, and gas mixture generated by fracturing will be discharged from the control hole. The discharged mixture is discharged into the anti-surge bag after passing through a tee. The anti-surge bag starts to expand rapidly from a folded state. By observing the changes in the anti-surge bag, it can be determined that the control hole and the blast hole are connected. After the discharge of the water-coal mixture decreases, or after the anti-surge bag is filled to more than 80%, the hydraulic fracturing operation in the blast hole is stopped, the casing of the control hole is separated from the tee, and the casing of the control hole is temporarily sealed. E. Then, hydraulic fracturing is performed again in the burst pressure hole, so that the fracture in the burst pressure hole continues to expand to other control holes. Observe the condition of the anti-impact bag corresponding to each control hole. If any anti-impact bag changes, repeat D to process the control hole. Repeat this process until the connection between all control holes and burst pressure holes is completed. F. After completing the connection between all control holes and blast holes, open each blocked casing and connect the gas extraction pipe corresponding to each control hole to the casing, so as to continue the gas extraction operation for each control hole.

2. The working method according to claim 1, characterized in that, The shockproof bag is made of flexible material and is folded when not in use.

3. The working method according to claim 1, characterized in that, During the gas drainage operation in step F, when the gas drainage concentration is low, the gas drainage work is stopped, and the process of steps D and E is repeated for each control hole and blast hole. This achieves repeated fracturing of the coal body between the blast holes and control holes, cleans the coal slime between the pores, further promotes the development and expansion of the fractures, and ultimately improves the gas drainage effect.

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