Quantitative feeding tool and method for methane in-situ combustion explosion fracturing combustion improver

Abstract

The invention discloses a quantitative throwing tool and method for a methane in-situ burning explosion fracturing combustion improver. The throwing tool comprises an inner barrel, a piston B and an outer barrel, the center of the upper end of the inner cylinder is fixedly connected with an air inlet pipeline B, and the bottom is provided with an inner cylinder bottom plate; a spraying hole is formed in the center area of the inner cylinder bottom plate, and a constant pressure plug is installed in the spraying hole. The piston B is assembled in the inner barrel; a plurality of perforations B are formed in the barrel body of the outer barrel, and an outer barrel bottom plate is arranged at the bottom of the outer barrel; the outer cylinder coaxially sleeves the inner cylinder, and the upper end of the outer cylinder is fixedly connected with the upper end of the inner cylinder. The method comprises the steps of installing the bridge plug in the shaft; the putting tool is put down to the position where the reservoir is located through a shaft by using a coiled tubing; a sealed putting section is formed at the position where the putting tool is located through the packer and the bridge plug; and the piston moves downwards until the combustion improver is completely filled into the sealed feeding section. According to the tool and the method, the pre-stored combustion improver can be conveniently and quantitatively put in a specific position.

Description

Technical Field

[0001] The present invention belongs to the technical field of transformation and exploitation of unconventional natural gas reservoirs, and in particular relates to a tool and method for quantitatively placing a methane in-situ explosion fracturing combustion aid. Background Art

[0002] my country has huge reserves of unconventional natural gas. As a clean energy, natural gas is expected to become an important energy source to replace coal in the future. However, due to the insufficient permeability of its reservoir, it is very difficult to mine and the mining efficiency is also very low. In order to ensure the mining efficiency, fracturing and permeability enhancement operations are usually required. At present, the main fracturing method is hydraulic fracturing, but hydraulic fracturing technology has many problems such as difficulty in drainage, waste of water resources, and severe environmental pollution.

[0003] In order to improve the fracturing effect of unconventional natural gas reservoirs and to avoid various problems existing in hydraulic fracturing, some scholars have proposed a fracturing technology using reservoir methane in situ explosion. This technology uses reservoir methane as fuel, and forms a methane-combustion-aid mixed gas at the bottom of the well or in the reservoir by artificially placing an oxidant. The methane-combustion-aid mixed gas is then detonated to produce instantaneous explosion high pressure, causing the reservoir to form impact cracks, thereby forming a complex three-dimensional fracture network, and ultimately achieving increased production and permeability of unconventional natural gas reservoirs. Compared with conventional hydraulic fracturing technology, methane in situ explosion fracturing technology can generate greater fracturing pressure, without wasting water resources, and can effectively solve problems such as environmental pollution, thus achieving the true meaning of "using local materials".

[0004] However, since the diameter of conventional fracturing wellbore is only about 120mm, the bottom space is relatively small. Under special working conditions, the depth of the methane reservoir can reach hundreds of meters or even thousands of meters. Therefore, it is difficult to implement quantitative, concentrated or uniform precise delivery of combustion aids in complex underground spaces. Achieving safe delivery of combustion aids in narrow deep underground spaces is a key technical problem that needs to be solved by this technology. At the same time, there are major safety hazards for the ultra-long-distance transportation of combustion aids along the way for continuous delivery of combustion aids. For this reason, it is urgently necessary to provide a tool and method for quantitative delivery of combustion aids for methane in-situ explosion fracturing, so as to solve the problems of difficulty, inaccuracy and uneven delivery of combustion aids caused by narrow deep underground spaces and great depths. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides a tool and method for quantitative delivery of combustion aids for methane in-situ explosion fracturing. The tool has a simple structure and high reliability. It can realize the pre-storage of quantitative combustion aids and can conveniently carry out quantitative delivery of the pre-stored combustion aids at a specific location by means of gas injection. The method has simple implementation steps and adopts a pre-charging delivery method, which can meet the needs of combustion aid delivery in different complex environments and can deliver the combustion aids in a targeted, quantitative and concentrated manner according to the size of the underground space and the delivery distance.

[0006] In order to achieve the above-mentioned invention object, the present invention provides a methane in-situ explosion fracturing combustion aid quantitative delivery tool, the delivery tool is a delivery body A, the delivery body A includes a gas storage cylinder, a piston A, a blocking slide, a telescopic sleeve rod and a limit block;

[0007] The upper end of the gas storage cylinder is open, and an air intake pipeline A is fixedly connected to the central area of ​​the upper end; the lower end of the gas storage cylinder is fixedly connected to a blocking block, and two perforations A are provided on opposite sides of the upper end of the blocking block; two arc-shaped grooves are provided on opposite sides of the upper part of the blocking block, and the outer edge surfaces of the two arc-shaped grooves are respectively in contact with the inner side walls of the opposite sides of the gas storage cylinder;

[0008] The outer diameter of the piston A is adapted to the inner diameter of the air storage cylinder, and the piston A is slidably and sealingly assembled inside the air storage cylinder, forming an air storage space A between the piston A and the barrier block;

[0009] The two blocking slides are respectively matched with the two arc-shaped grooves, and a pair of holes are opened opposite to each other; the two blocking slides are respectively slidably assembled in the two arc-shaped grooves in the vertical direction, and the outer arc surfaces of the two blocking slides are slidably sealed with the inner side walls of the opposite sides of the gas storage cylinder; when the two blocking slides are completely embedded in the two arc-shaped grooves, the upper ends of the two blocking slides are located above the two perforations A, and the two holes on the two blocking slides are respectively aligned with the two perforations A;

[0010] Two telescopic sleeve rods are vertically distributed above the two blocking slides, the lower ends of the telescopic sections are respectively fixedly connected to the centers of the upper ends of the two blocking slides, and the fixed sections are respectively fixedly inserted at the opposite sides of the lower part of the piston A;

[0011] The two limit blocks are relatively distributed above the two arc-shaped grooves and are fixedly connected to the opposite sides of the inner wall of the gas storage cylinder; the lower ends of the two limit blocks are respectively abutted against the upper ends of the two blocking slides, and when the upper ends of the two blocking slides are abutted against the lower ends of the two limit blocks, the lower ends of the two blocking slides are located below the two perforations A.

[0012] As a preferred embodiment, the lower end of the air intake pipe A is fixedly connected to the upper end of the air storage cylinder via an annular connecting plate A. The annular connecting plate A can also be used to limit the maximum upward travel of the piston A, thereby preventing the piston A from slipping off the air storage cylinder.

[0013] In the present invention, two arc-shaped grooves are provided on opposite sides of the upper part of the barrier block at the lower end of the gas storage cylinder, and two barrier slides are slidably mounted in the two arc-shaped grooves. At the same time, two perforations A are provided on the gas storage cylinder, and two holes are correspondingly provided on the two barrier slides. In this way, the two perforations A can be blocked or opened by changing the height of the two barrier slides in the two arc-shaped grooves. When the two perforations A are blocked, the air storage space A can be sealed, thereby enabling the pre-storage of the combustion aid. When the two perforations A are opened, the combustion aid pre-stored in the gas storage space A can be quickly discharged through the perforations A. The piston A which is slidably and sealingly assembled in the gas storage cylinder is connected to the upper ends of the two blocking slides through two telescopic rods. At the same time, the two blocking slides are limited to the maximum upward stroke by two limit blocks fixed on the inner wall of the gas storage cylinder, so that the movement process of the piston A can be connected with the blocking action and the opening action of the two blocking slides. In this way, during the process of filling the combustion-supporting agent, the piston A away from the blocking block can be used to drive the two telescopic sleeves to reach the extended state, and can drive the two blocking slides to reach the two limit blocks. In this way, the two holes and the two perforations A can be in a staggered state, and at the same time, the two blocking slides can be used to fit the inner wall of the gas storage cylinder to ensure the sealing state of the gas storage space A; at the same time, during the compression of the piston A, the two telescopic sleeves can be compressed by the piston A to reach a contracted state, and at the same time, the two blocking slides are pushed to be completely embedded in the two arc-shaped slides, so that the two holes and the two perforations A can be aligned and connected, and then the gas storage space A can be connected to the outside through the perforations A. The tool has a simple structure and high reliability. It can realize the pre-storage of quantitative combustion aids, and can conveniently use gas injection to quantitatively place the pre-stored combustion aids at a specific position.

[0014] The present invention also provides a quantitative porous delivery tool for methane in-situ explosion fracturing combustion aid, wherein the delivery tool is a delivery body B, and the delivery body B comprises an inner cylinder, a piston B and an outer cylinder;

[0015] The upper end of the inner cylinder is open, and an air intake pipe B is fixedly connected to the center of the upper end, and the bottom thereof has an inner cylinder bottom plate; a spray hole is opened in the central area of ​​the inner cylinder bottom plate, and a constant pressure plug is installed in the spray hole;

[0016] The outer diameter of the piston B matches the inner diameter of the inner cylinder, and the piston B is slidably and sealingly assembled inside the inner cylinder, forming an air storage space B between the piston B and the bottom plate of the inner cylinder;

[0017] The upper end of the outer cylinder is an open structure, with a plurality of perforations B provided on the cylinder, and an outer cylinder bottom plate provided at the bottom; the outer cylinder is coaxially sleeved on the outside of the inner cylinder, and the upper end thereof is fixedly connected to the upper end of the inner cylinder through an annular connecting plate B, and at the same time, an annular cavity is formed between the inner cylinder and the outer cylinder.

[0018] As a preferred embodiment, the cross section of the outer cylinder bottom plate is in the shape of an inverted frustum, which can play a role in rapid flow diversion, and is conducive to the combustion-supporting agent discharged from the spray hole to quickly reach the perforation B, which is conducive to the rapid completion of the delivery operation.

[0019] Furthermore, in order to effectively expand the delivery range of the combustion aid, the plurality of perforations B are evenly divided into four groups from top to bottom, and each group is composed of four perforations B evenly distributed circumferentially on the same plane.

[0020] In the present invention, the outer cylinder is coaxially sleeved on the outer side of the inner cylinder, and at the same time, the upper end of the outer cylinder is fixedly connected to the upper end of the inner cylinder through the annular connecting plate B, so that an annular cavity can be formed between the inner cylinder and the outer cylinder. The piston B is slidably and sealedly assembled in the inner cylinder, so that a closed gas storage space B can be formed between the piston B and the inner cylinder, which is conducive to the pre-storage operation of quantitative combustion-supporting agent. A spray hole is opened on the bottom plate of the inner cylinder, and a constant pressure plug is installed in the spray hole, so that the air tightness of the gas storage space B can be ensured under normal conditions. At the same time, after the pressure in the gas storage space B reaches the opening pressure of the constant pressure plug, the gas storage space B and the annular cavity can be quickly connected. A plurality of perforations B are opened on the barrel of the outer cylinder, which can effectively connect the annular cavity with the external space, and then after the gas storage space B is connected with the annular cavity, the combustion-supporting agent can be quickly ejected through the spray hole, the annular cavity and the perforations B, and reach the predetermined delivery position. The tool has a simple structure and high reliability, can realize the pre-storage of quantitative combustion aid, and can conveniently perform quantitative delivery of the pre-stored combustion aid at a specific location by means of gas injection.

[0021] The present invention also provides a method for quantitatively placing a methane in-situ explosion fracturing combustion aid, using a methane in-situ explosion fracturing combustion aid quantitative placement tool or a methane in-situ explosion fracturing combustion aid quantitative multi-porous placement tool, comprising the following steps:

[0022] Step 1: Fill the required amount of combustion aid into the delivery tool according to the amount of combustion aid required by the reservoir;

[0023] Step 2: On the ground, a fracturing vehicle is arranged on one side of the wellbore where the fracturing operation is to be performed. At the same time, a section of coiled tubing is prepared, and a packer is installed on the outside of the lower end of the coiled tubing;

[0024] Step 3: Install a bridge plug in the wellbore and set the bridge plug below the reservoir;

[0025] Step 4: Connect the lower end of the coiled tubing to the feed pipeline on the delivery tool, and use the coiled tubing to lower the delivery tool through the wellbore to the location of the reservoir, and then connect the upper end of the coiled tubing to the output pipeline of the fracturing truck;

[0026] Step 5: Pump nitrogen into the coiled tubing through the fracturing truck, use the high-pressure nitrogen to set the packer, and use the packer and the bridge plug to form a sealed delivery section at the location of the delivery tool;

[0027] Step 6: Continue to pump high-pressure nitrogen into the coiled tubing through the fracturing truck, and use the increasing pressure of nitrogen to act on the upper end surface of the piston in the delivery tool to move the piston downward until the combustion aid in the gas storage space is completely filled into the sealed delivery section through the perforations, thereby completing the quantitative delivery of the combustion aid.

[0028] As a preferred embodiment, in step one, when the delivery tool is delivery body A, the combustion aid is charged into the gas storage space A; when the delivery tool is delivery body B, the combustion aid is charged into the gas storage space B.

[0029] As a preferred embodiment, in step six, when the delivery tool is the delivery body A, under the action of the increasing pressure of nitrogen, the piston A moves downward and shrinks the length of the two telescopic sleeve rods. At the same time, the two blocking slides are pushed to slide toward the bottom of the two arc-shaped grooves by the two telescopic sleeve rods. When the two blocking slides are completely embedded in the two arc-shaped grooves, the two holes on the two blocking slides are respectively aligned with the two perforations A and connected, and the combustion-supporting agent in the gas storage space A is ejected at a high speed through the connected holes and perforations A, and is fully mixed with the in-situ methane in the reservoir space;

[0030] When the input tool is the input body B, under the action of the nitrogen with increasing pressure, the piston B moves downward, and the pressure in the gas storage space B is continuously increased by the compression effect of the downward moving piston B. When the pressure in the gas storage space B reaches the opening pressure of the constant pressure plug, the constant pressure plug is pressed out of the spray hole, and the combustion-supporting agent in the gas storage space B is ejected at high speed through the spray hole, the annular cavity and the perforation B in turn, and is fully mixed with the in-situ methane in the reservoir space.

[0031] In the present invention, the required amount of combustion aid is pre-stored in the delivery tool, which can avoid the transportation process of the combustion aid along the way, and the delivery operation of the combustion aid can be carried out after the delivery tool reaches the predetermined position. The air intake pipeline of the delivery tool is connected with the fracturing vehicle by a continuous oil pipe, which can facilitate the use of the continuous oil pipe to lower the delivery tool to the target reservoir position. A bridge plug is first installed at the position below the reservoir in the wellbore, and at the same time, a packer is installed on the outside of the continuous oil pipe. After the delivery tool is lowered to the predetermined position, the packer and the bridge plug can be used to form a sealed delivery section at the location of the delivery tool. The piston B is pushed downward by pumping in high-pressure nitrogen, thereby pressurizing the combustion aid in the gas storage space B. During the pressurization process, the constant pressure plug can be automatically pressed out of the spray hole, so that the spray hole and the annular cavity can be quickly connected. As a result, the pre-stored combustion aid can be quickly released into the sealed release section. In this way, it can be ensured that the combustion aid is released into the closed space at the bottom of the well, and the methane in the gas storage can be fully mixed with the combustion aid under closed conditions, ensuring that the methane explosion fracturing is carried out in the closed section of the wellbore.

[0032] The method has simple implementation steps and adopts a pre-charging and delivery method, which helps to achieve an efficient combination of conventional staged fracturing technology and pre-charging quantitative delivery technology, can meet the needs of combustion aid delivery in different complex environments, and can deliver combustion aids in a targeted, quantitative and concentrated manner according to the size of the underground space and the delivery distance. In addition, it can also meet the needs of uniform delivery of combustion aids in deep and narrow spaces, can make the combustion aid more fully mixed with the in-situ methane in the underground reservoir space, and can prevent the instantaneous high pressure generated by the explosion of the methane-combustion aid mixture from affecting ground equipment, thereby ensuring the safety of the delivery of methane in-situ explosion fracturing combustion aids. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a three-dimensional structural diagram of the first embodiment of the delivery tool of the present invention;

[0034] Figure 2 yes Figure 1 A longitudinal cross-sectional view of

[0035] Figure 3 is a three-dimensional structural diagram of a second embodiment of the delivery tool of the present invention;

[0036] Figure 4 yes Figure 3 A longitudinal cross-sectional view of

[0037] Figure 5 yes Figure 3 Half-section of

[0038] Figure 6 This is a schematic diagram of the state of the present invention using the delivery tool in the first embodiment to deliver the combustion aid;

[0039] Figure 7 It is a schematic diagram of the state of the present invention using the delivery tool in the second embodiment to deliver the combustion aid.

[0040] In the figure: 1. piston A, 2. inner cylinder, 3. air storage cylinder, 4. combustion aid, 5. air inlet pipeline A, 6. continuous oil pipe, 7. spray hole, 8. constant pressure plug, 9. annular connecting plate A, 10. barrier block, 11. annular cavity, 12. perforation A, 13. fracturing vehicle, 14. nitrogen, 15. wellbore, 16. reservoir, 17. telescopic sleeve, 18. limit block, 19. eyelet, 20. barrier slide plate, 21. arc groove, 22. delivery tool, 23. outer cylinder, 24. piston B, 25. air inlet pipeline B, 26. inner cylinder bottom plate, 27. perforation B, 28. outer cylinder bottom plate, 29. annular connecting plate B, 30. bridge plug, 31. packer. DETAILED DESCRIPTION

[0041] The present invention will be further described below in conjunction with the accompanying drawings.

[0042] like Figure 1 and Figure 2 As shown, the present invention provides a methane in-situ explosion fracturing combustion aid quantitative delivery tool, the delivery tool 22 is a delivery body A, the delivery body A includes a gas storage cylinder 3, a piston A1, a blocking slide 20, a telescopic sleeve rod 17 and a limit block 18;

[0043] The upper end of the gas storage cylinder 3 is open, and an air intake pipeline A5 is fixedly connected to the central area of ​​the upper end; the lower end of the gas storage cylinder 3 is fixedly connected to a blocking block 10, and two perforations A12 are provided on opposite sides of the upper end of the blocking block 10; two arc-shaped grooves 21 are provided on opposite sides of the upper part of the blocking block 10, and the outer edge surfaces of the two arc-shaped grooves 21 are respectively in contact with the inner side walls of the opposite sides of the gas storage cylinder 3;

[0044] The outer diameter of the piston A1 is matched with the inner diameter of the gas storage cylinder 3, and the piston A1 is slidably and sealingly assembled inside the gas storage cylinder 3, forming a gas storage space A between the piston A1 and the barrier block 10; the gas storage space A is used to store the combustion aid 4;

[0045] The two blocking slides 20 are respectively matched with the two arc-shaped grooves 21, and a pair of holes 19 are opened opposite to each other; the two blocking slides 20 are respectively slidably assembled in the two arc-shaped grooves 21 vertically, and the outer arc surfaces of the two blocking slides 20 are slidably sealed with the inner side walls of the opposite sides of the gas storage cylinder 3; when the two blocking slides 20 are completely embedded in the two arc-shaped grooves 21, the upper ends of the two blocking slides 20 are located above the two perforations A12, and the two holes 19 on the two blocking slides 20 are respectively aligned with the two perforations A12;

[0046] The two telescopic rods 17 are vertically distributed above the two blocking slides 20, and the lower ends of their telescopic sections are fixedly connected to the centers of the upper ends of the two blocking slides 20, and the fixed sections are fixedly inserted on the opposite sides of the lower part of the piston A1; as a preferred embodiment, the fixed section of the telescopic rod 17 is completely inserted into the interior of the piston A1, and at the same time, the telescopic section of the telescopic rod 17 can be completely retracted into the fixed section, so that the downward displacement of the piston A1 can be maximized, so that the combustion aid 4 in the gas storage space A can be discharged as completely as possible.

[0047] The two limit blocks 18 are relatively distributed above the two arc-shaped grooves 21 and are fixedly connected to the opposite sides of the inner wall of the gas storage cylinder 3; the lower ends of the two limit blocks 18 are respectively abutted against the upper ends of the two blocking slides 20, and when the upper ends of the two blocking slides 20 are abutted against the lower ends of the two limit blocks 18, the lower ends of the two blocking slides 20 are located below the two perforations A12.

[0048] As a preferred embodiment, the lower end of the air intake pipe A5 is fixedly connected to the upper end of the air storage cylinder 3 through an annular connecting plate A9. The annular connecting plate A can also be used to limit the maximum upward travel of the piston A, thereby preventing the piston A from slipping off the air storage cylinder. The annular connecting plate A9 is sealedly connected to the air intake pipe A5 and the upper end of the air storage cylinder 3 to maintain air tightness at the connection position.

[0049] As a preferred embodiment, the barrier block 10 is connected with a one-way air intake valve connected to the air storage space A, so that the combustion aid 4 can be conveniently filled into the air storage space A through the one-way air intake valve. During the process of filling the combustion aid 4, the piston A1 is pushed to the maximum upward displacement. At this time, the two limit blocks 18 abut against the upper ends of the two barrier sliders 20 to achieve the upward limit of the two barrier sliders 20. At the same time, the two retractable sleeve rods 17 reach the maximum extension state. In this state, the two holes 19 on the two barrier sliders 20 are staggered with the two perforations A12, and the air storage air A forms a closed space.

[0050] In the present invention, two arc-shaped grooves are provided on opposite sides of the upper part of the barrier block at the lower end of the gas storage cylinder, and two barrier slides are slidably mounted in the two arc-shaped grooves. At the same time, two perforations A are provided on the gas storage cylinder, and two holes are correspondingly provided on the two barrier slides. In this way, the two perforations A can be blocked or opened by changing the height of the two barrier slides in the two arc-shaped grooves. When the two perforations A are blocked, the air storage space A can be sealed, thereby enabling the pre-storage of the combustion aid. When the two perforations A are opened, the combustion aid pre-stored in the gas storage space A can be quickly discharged through the perforations A. The piston A which is slidably and sealingly assembled in the gas storage cylinder is connected to the upper ends of the two blocking slides through two telescopic rods. At the same time, the two blocking slides are limited to the maximum upward stroke by two limit blocks fixed on the inner wall of the gas storage cylinder, so that the movement process of the piston A can be connected with the blocking action and the opening action of the two blocking slides. In this way, during the process of filling the combustion-supporting agent, the piston A away from the blocking block can be used to drive the two telescopic sleeves to reach the extended state, and can drive the two blocking slides to reach the two limit blocks. In this way, the two holes and the two perforations A can be in a staggered state, and at the same time, the two blocking slides can be used to fit the inner wall of the gas storage cylinder to ensure the sealing state of the gas storage space A; at the same time, during the compression of the piston A, the two telescopic sleeves can be compressed by the piston A to reach a contracted state, and at the same time, the two blocking slides are pushed to be completely embedded in the two arc-shaped slides, so that the two holes and the two perforations A can be aligned and connected, and then the gas storage space A can be connected to the outside through the perforations A. The tool has a simple structure and high reliability. It can realize the pre-storage of quantitative combustion aids, and can conveniently use gas injection to quantitatively place the pre-stored combustion aids at a specific position.

[0051] like Figures 3 to 5 As shown, the present invention also provides a quantitative porous delivery tool for methane in-situ explosion fracturing combustion aid, wherein the delivery tool 22 is a delivery body B, and the delivery body B includes an inner cylinder 2, a piston B24 and an outer cylinder 23;

[0052] The upper end of the inner cylinder 2 is open, and an air intake pipe B25 is fixedly connected to the center of the upper end, and the bottom thereof is provided with an inner cylinder bottom plate 26; a spray hole 7 is provided in the central area of ​​the inner cylinder bottom plate 26, and a constant pressure plug 8 is installed in the spray hole 7; the constant pressure plug 8 automatically detaches from the spray hole 7 when the upper acting pressure reaches a set pressure value;

[0053] The outer diameter of the piston B24 matches the inner diameter of the inner cylinder 2, and the piston B24 is slidably and sealingly assembled inside the inner cylinder 2, forming an air storage space B between the piston B24 and the inner cylinder bottom plate 26; the air storage space B is used to store the combustion aid 4;

[0054] The upper end of the outer cylinder 23 is an open structure, with a plurality of perforations B27 formed on the cylinder, and an outer cylinder bottom plate 28 at the bottom; the outer cylinder 23 is coaxially sleeved on the outside of the inner cylinder 2, and its upper end is fixedly connected to the upper end of the inner cylinder 2 through an annular connecting plate B29, and at the same time, an annular cavity 11 is formed between the inner cylinder 2 and the outer cylinder 23. The annular connecting plate B29 is sealed to the outer surface of the inner cylinder 2 and the upper end of the outer cylinder 23 to ensure the airtightness of the annular cavity formed subsequently;

[0055] As a preferred embodiment, the cross section of the outer cylinder bottom plate 28 is in the shape of an inverted frustum. In this way, it can play a role in rapid flow diversion, which is conducive to the combustion-supporting agent discharged from the spray hole to quickly reach the perforation B, and is conducive to the rapid completion of the delivery operation.

[0056] In order to effectively expand the delivery range of the combustion aid, the plurality of perforations B27 are evenly divided into four groups from top to bottom, and each group is composed of four perforations B27 evenly distributed circumferentially on the same plane.

[0057] As a preferred embodiment, the inner cylinder bottom plate 26 is connected to an inflation pipeline connected to the air storage space B, and the air inlet end of the inflation pipeline passes through the outer cylinder bottom plate 28 to reach the lower side of the outer cylinder body 28. At the same time, a one-way valve is installed at the air inlet end of the inflation pipeline. In this way, the combustion aid 4 can be conveniently filled into the air storage space B through the one-way valve and the inflation pipeline. During the process of filling the combustion aid 4, the piston B24 is pushed to the maximum upward displacement. At this time, the annular connecting plate B29 abuts against the piston B24 to achieve the upper limit position of the piston B24.

[0058] In the present invention, the outer cylinder is coaxially sleeved on the outer side of the inner cylinder, and at the same time, the upper end of the outer cylinder is fixedly connected to the upper end of the inner cylinder through the annular connecting plate B, so that an annular cavity can be formed between the inner cylinder and the outer cylinder. The piston B is slidably and sealedly assembled in the inner cylinder, so that a closed gas storage space B can be formed between the piston B and the inner cylinder, which is conducive to the pre-storage operation of quantitative combustion-supporting agent. A spray hole is opened on the bottom plate of the inner cylinder, and a constant pressure plug is installed in the spray hole, so that the air tightness of the gas storage space B can be ensured under normal conditions. At the same time, after the pressure in the gas storage space B reaches the opening pressure of the constant pressure plug, the gas storage space B and the annular cavity can be quickly connected. A plurality of perforations B are opened on the barrel of the outer cylinder, which can effectively connect the annular cavity with the external space, and then after the gas storage space B is connected with the annular cavity, the combustion-supporting agent can be quickly ejected through the spray hole, the annular cavity and the perforations B, and reach the predetermined delivery position. The tool has a simple structure and high reliability, can realize the pre-storage of quantitative combustion aid, and can conveniently perform quantitative delivery of the pre-stored combustion aid at a specific location by means of gas injection.

[0059] The present invention can meet the combustion aid delivery requirements in different complex environments by providing two types of methane in-situ explosion fracturing combustion aid delivery tools, namely, delivery body A and delivery body B.

[0060] like Figure 6 and Figure 7 As shown, the present invention also provides a method for quantitatively placing a methane in-situ explosion fracturing combustion aid, using a methane in-situ explosion fracturing combustion aid quantitative placement tool or a methane in-situ explosion fracturing combustion aid quantitative placement tool, comprising the following steps:

[0061] Step 1: according to the combustion-aiding agent dosage required by the reservoir 16, the required amount of the combustion-aiding agent 4 is charged into the delivery tool 22;

[0062] Step 2: Arrange a fracturing vehicle 13 on the ground at one side of the wellbore 15 to be subjected to fracturing operation, prepare a section of coiled tubing 6, and install a packer 31 on the outside of the lower end of the coiled tubing 6;

[0063] Step 3: installing the bridge plug 30 in the wellbore 15 and setting the bridge plug 30 below the reservoir 16;

[0064] Step 4: Connect the lower end of the coiled tubing 6 to the feed pipeline on the delivery tool 22, and use the coiled tubing 6 to lower the delivery tool 22 through the wellbore 15 to the location of the reservoir 16, and then connect the upper end of the coiled tubing 6 to the output pipeline of the fracturing vehicle 13;

[0065] Step 5: nitrogen 14 is pumped into the coiled tubing 6 through the fracturing truck 13, the high-pressure nitrogen 14 is used to seal the packer 31, and the packer 31 and the bridge plug 30 are used to form a sealed delivery section at the location of the delivery tool 22;

[0066] Step six: Continue to pump high-pressure nitrogen 14 into the coiled tubing 6 through the fracturing truck 13, and use the nitrogen 14 with increasing pressure to act on the upper end surface of the piston in the delivery tool 22, so that the piston in the delivery tool 22 moves downward until the combustion aid 4 in the gas storage space is completely filled into the sealed delivery section through the perforations, thereby completing the quantitative delivery operation of the combustion aid 4.

[0067] As a preferred embodiment, in step one, when the delivery tool 22 is the delivery body A, the combustion aid 4 is charged into the gas storage space A; when the delivery tool 22 is the delivery body B, the combustion aid 4 is charged into the gas storage space B.

[0068] As a preferred embodiment, in step six, when the delivery tool 22 is the delivery body A, under the action of the nitrogen 14 with increasing pressure, the piston A1 moves downward and shrinks the length of the two telescopic sleeve rods 17. At the same time, the two blocking slides 20 are pushed to slide to the bottom of the two arc-shaped grooves 21 by the two telescopic sleeve rods 17. When the two blocking slides 20 are completely embedded in the two arc-shaped grooves 21, the two holes 19 on the two blocking slides 20 are respectively aligned with and connected to the two perforations A12, and the combustion-supporting agent 4 in the gas storage space A is ejected at a high speed through the connected holes 19 and perforations A12, and is fully mixed with the in-situ methane in the reservoir 16 space, thereby realizing the quantitative centralized delivery operation of the pre-charged combustion-supporting agent 4 in the delivery tool 22;

[0069] When the injection tool 22 is the injection body B, under the action of the nitrogen 14 with increasing pressure, the piston B24 moves downward, and the pressure in the gas storage space B is continuously increased by the compression effect of the downward piston B24. When the pressure in the gas storage space B reaches the opening pressure of the constant pressure plug 8, the constant pressure plug 8 is pressed out of the spray hole 7, and the combustion aid 4 in the gas storage space B is ejected at high speed through the spray hole 7, the annular cavity 11 and the perforation B27 in turn, and is fully mixed with the in-situ methane in the reservoir 16 space. In this way, the quantitative centralized injection operation of the pre-filled combustion aid 4 in the injection tool 22 is realized.

[0070] In the present invention, the required amount of combustion aid is pre-stored in the delivery tool, which can avoid the transportation process of the combustion aid along the way, and the delivery operation of the combustion aid can be carried out after the delivery tool reaches the predetermined position. The air intake pipeline of the delivery tool is connected with the fracturing vehicle by a continuous oil pipe, which can facilitate the use of the continuous oil pipe to lower the delivery tool to the target reservoir position. A bridge plug is first installed at the position below the reservoir in the wellbore, and at the same time, a packer is installed on the outside of the continuous oil pipe. After the delivery tool is lowered to the predetermined position, the packer and the bridge plug can be used to form a sealed delivery section at the location of the delivery tool. The piston B is pushed downward by pumping in high-pressure nitrogen, thereby pressurizing the combustion aid in the gas storage space B. During the pressurization process, the constant pressure plug can be automatically pressed out of the spray hole, so that the spray hole and the annular cavity can be quickly connected. As a result, the pre-stored combustion aid can be quickly released into the sealed release section. In this way, it can be ensured that the combustion aid is released into the closed space at the bottom of the well, and the methane in the gas storage can be fully mixed with the combustion aid under closed conditions, ensuring that the methane explosion fracturing is carried out in the closed section of the wellbore.

[0071] The method has simple implementation steps and adopts a pre-charging and delivery method, which helps to achieve an efficient combination of conventional staged fracturing technology and pre-charging quantitative delivery technology, can meet the needs of combustion aid delivery in different complex environments, and can deliver combustion aids in a targeted, quantitative and concentrated manner according to the size of the underground space and the delivery distance. In addition, it can also meet the needs of uniform delivery of combustion aids in deep and narrow spaces, can make the combustion aid more fully mixed with the in-situ methane in the underground reservoir space, and can prevent the instantaneous high pressure generated by the explosion of the methane-combustion aid mixture from affecting ground equipment, thereby ensuring the safety of the delivery of methane in-situ explosion fracturing combustion aids.

Claims

1. A quantitative delivery tool for methane in-situ explosive fracturing combustion aid, wherein the delivery tool (22) is a delivery body A, and the delivery body A includes a gas storage cylinder (3), characterized in that: It also includes a piston A (1), a blocking slide (20), a telescopic sleeve rod (17) and a limit block (18); The upper end of the gas storage cylinder (3) is open, and an air intake pipeline A (5) is fixedly connected to the central area of ​​the upper end; the lower end of the gas storage cylinder (3) is fixedly connected to a blocking block (10), and two perforations A (12) are provided on opposite sides of the upper end of the blocking block (10); two arc-shaped grooves (21) are provided on opposite sides of the upper part of the blocking block (10), and the outer edge surfaces of the two arc-shaped grooves (21) are respectively in contact with the inner side walls of the opposite sides of the gas storage cylinder (3); The outer diameter of the piston A (1) is matched with the inner diameter of the air storage cylinder (3), and the piston A (1) is slidably and sealingly mounted inside the air storage cylinder (3), forming an air storage space A between the piston A (1) and the barrier block (10); The two blocking slides (20) are respectively matched with the two arc-shaped grooves (21), and a pair of holes (19) are opened opposite to each other; the two blocking slides (20) are respectively slidably assembled in the two arc-shaped grooves (21) in the vertical direction, and the outer arc surfaces of the two blocking slides (20) are slidably sealed with the inner side walls of the gas storage cylinder (3) on the opposite sides; when the two blocking slides (20) are completely embedded in the two arc-shaped grooves (21), the upper ends of the two blocking slides (20) are located above the two perforations A (12), and the two holes (19) on the two blocking slides (20) are respectively aligned with the two perforations A (12); Two telescopic sleeve rods (17) are vertically distributed above the two blocking slides (20), the lower ends of the telescopic sections are respectively fixedly connected to the centers of the upper ends of the two blocking slides (20), and the fixed sections are respectively fixedly inserted at the opposite sides of the lower part of the piston A (1); The two limit blocks (18) are relatively distributed above the two arc-shaped grooves (21) and are respectively fixedly connected to the opposite sides of the inner wall of the gas storage cylinder (3); the lower ends of the two limit blocks (18) are respectively abutted against the upper ends of the two blocking slides (20), and when the upper ends of the two blocking slides (20) are abutted against the lower ends of the two limit blocks (18), the lower ends of the two blocking slides (20) are located below the two perforations A (12).

2. A methane in-situ explosion fracturing combustion aid quantitative delivery tool according to claim 1, characterized in that: The lower end of the air intake pipeline A (5) is fixedly connected to the upper end of the air storage cylinder (3) via an annular connecting plate A (9).

3. A quantitative porous delivery tool for methane in-situ explosive fracturing combustion aid, wherein the delivery tool (22) is a delivery body B, and the delivery body B comprises an inner cylinder (2), characterized in that: It also includes a piston B (24) and an outer cylinder (23); The upper end of the inner cylinder (2) is open, and an air intake pipeline B (25) is fixedly connected to the center of the upper end, and the bottom thereof is provided with an inner cylinder bottom plate (26); a spray hole (7) is opened in the central area of ​​the inner cylinder bottom plate (26), and a constant pressure plug (8) is installed in the spray hole (7); The outer diameter of the piston B (24) is matched with the inner diameter of the inner cylinder (2), and the piston B (24) is slidably and sealingly assembled inside the inner cylinder (2), forming an air storage space B between the piston B (24) and the inner cylinder bottom plate (26); The upper end of the outer cylinder (23) is an open structure, and a plurality of perforations B (27) are formed on the cylinder, and the bottom of the outer cylinder (23) has an outer cylinder bottom plate (28); the outer cylinder (23) is coaxially sleeved on the outside of the inner cylinder (2), and the upper end of the outer cylinder (2) is fixedly connected to the upper end of the inner cylinder (2) through an annular connecting plate B (29), and at the same time, an annular cavity (11) is formed between the inner cylinder (2) and the outer cylinder (23).

4. A quantitative multi-porous delivery tool for methane in-situ explosion fracturing combustion aid according to claim 3, characterized in that: The cross section of the outer cylinder bottom plate (28) is in the shape of an inverted frustum.

5. A quantitative multi-porous delivery tool for methane in-situ explosion fracturing combustion aid according to claim 3, characterized in that: The plurality of perforations B (27) are evenly divided into four groups from top to bottom, and each group consists of four perforations B (27) evenly distributed circumferentially on the same plane.

6. A method for quantitatively placing a methane in-situ explosion fracturing combustion aid, using a methane in-situ explosion fracturing combustion aid quantitative placement tool as claimed in claim 1 or a methane in-situ explosion fracturing combustion aid quantitative porous placement tool as claimed in claim 3, characterized in that: The following steps are involved: Step 1: according to the amount of combustion aid required by the reservoir (16), the required amount of combustion aid (4) is charged into the delivery tool (22); Step 2: On the ground, a fracturing vehicle (13) is arranged at one side of the wellbore (15) to be subjected to fracturing operation. At the same time, a section of coiled tubing (6) is prepared, and a packer (31) is installed outside the lower end of the coiled tubing (6); Step 3: installing a bridge plug (30) in the wellbore (15), and setting the bridge plug (30) below the reservoir (16); Step 4: Connect the lower end of the coiled tubing (6) to the feed pipeline on the delivery tool (22), and use the coiled tubing (6) to lower the delivery tool (22) through the wellbore (15) to the location of the reservoir (16), and then connect the upper end of the coiled tubing (6) to the output pipeline of the fracturing vehicle (13); Step 5: nitrogen (14) is pumped into the coiled tubing (6) through the fracturing vehicle (13), the high-pressure nitrogen (14) is used to seal the packer (31), and the packer (31) and the bridge plug (30) are used to form a sealed delivery section at the location of the delivery tool (22); Step 6: Continue to pump high-pressure nitrogen (14) into the coiled tubing (6) through the fracturing vehicle (13), and use the nitrogen (14) with increasing pressure to act on the upper end surface of the piston in the delivery tool (22), so that the piston in the delivery tool (22) moves downward until the combustion aid (4) in the gas storage space is completely filled into the sealed delivery section through the perforations, thereby completing the quantitative delivery operation of the combustion aid (4).

7. A method for quantitatively placing a methane in-situ explosion fracturing combustion aid according to claim 6, characterized in that: In step one, when the delivery tool (22) is delivery body A, the combustion aid (4) is charged into the gas storage space A; when the delivery tool (22) is delivery body B, the combustion aid (4) is charged into the gas storage space B.

8. The method for quantitatively placing a methane in-situ explosion fracturing combustion aid according to claim 6, characterized in that: In step six, when the delivery tool (22) is the delivery body A, under the action of the nitrogen (14) with increasing pressure, the piston A (1) moves downward and shrinks the length of the two telescopic sleeve rods (17). At the same time, the two telescopic sleeve rods (17) push the two blocking slides (20) to slide toward the bottom of the two arc-shaped grooves (21). When the two blocking slides (20) are completely embedded in the two arc-shaped grooves (21), the two holes (19) on the two blocking slides (20) are respectively aligned with and connected to the two perforations A (12). The combustion aid (4) in the gas storage space A is ejected at a high speed through the connected holes (19) and perforations A (12) and is fully mixed with the in-situ methane in the reservoir (16) space. When the input tool (22) is the input body B, the piston B (24) moves downward under the action of the nitrogen (14) with increasing pressure, and the pressure in the gas storage space B is continuously increased by the compression effect of the downwardly moving piston B (24). When the pressure in the gas storage space B reaches the opening pressure of the constant pressure plug (8), the constant pressure plug (8) is pressed out of the spray hole (7), and the combustion-supporting agent (4) in the gas storage space B is ejected at a high speed through the spray hole (7), the annular cavity (11) and the perforation B (27) in sequence, and is fully mixed with the in-situ methane in the reservoir (16) space.

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