An adjustable pressure bladder-type hydraulic fracturing orifice sealer

Abstract

This invention discloses an adjustable pressure liquid-filled bladder type hydraulic fracturing borehole sealer, relating to the field of geological exploration technology. It includes a housing, inside which are two upper gaskets and two lower gaskets arranged opposite each other, with a high-pressure filling tube positioned between them. A liquid bladder is mounted on each of the lower gaskets, and the liquid bladder has a central channel inside, with the high-pressure filling tube disposed within the central channel. A liquid filling cavity is located inside the liquid bladder, and a liquid bladder storage cavity is located in the middle of the housing for filling with liquid and expanding. By injecting water and pressurizing the liquid bladder, the borehole is sealed and components can be disassembled through the expansion and contraction of the liquid bladder. When the liquid bladder expands, it seals the gap between the high-pressure filling tube and the central channel of the liquid bladder, as well as the gap between the liquid bladder and the housing. When the liquid bladder contracts, the high-pressure filling tube can be removed from the central channel of each component. This single liquid bladder provides two sealing effects, facilitating disassembly and improving work efficiency.

Description

Technical Field

[0001] This invention belongs to the field of geological exploration technology, specifically relating to an adjustable pressure liquid bladder type hydraulic fracturing orifice sealer. Background Technology

[0002] Hydraulic fracturing method for geostress testing is a core technology for obtaining absolute geostress in deep underground engineering and regional geological research. Its significance lies not only in accurately determining the magnitude, direction, and distribution characteristics of geostress, but also in providing the most basic force source data support for the design, construction, and safety management of geotechnical engineering throughout its entire life cycle. At the same time, it makes up for the shortcomings of other geostress testing methods in deep and complex geological conditions, and is adapted to the strategic needs of my country's current deep resource development and major underground engineering construction.

[0003] Patent document No. 201711265097.9, authorized on March 8, 2024, entitled "A High-Pressure In-Bore Drainage and Pressure Relief Hydraulic Grouting and Pressure Test Plug," belongs to the field of in-hole segmented isolation equipment in grouting and pressure testing. It features an eccentric variable-diameter connector threaded to a drainage and pressure relief mechanism, a high-pressure filling pipe threaded to the drainage and pressure relief mechanism, a plug capsule threaded to the drainage and pressure relief mechanism, an upper end of a core tube threaded to the drainage and pressure relief mechanism, and a lower end of the core tube slidably connected to the lower end of the plug capsule. A high-pressure grouting pipe is fixedly connected to the drainage and pressure relief mechanism and passes through the eccentric variable-diameter connector and the core tube. By utilizing the pressure difference balance principle, it reliably achieves repeated filling and thorough drainage and pressure relief of the plug capsule within the borehole. This has been fully verified in engineering practice, exhibiting strong geological adaptability and promising application prospects in grouting, pressure testing, fracturing tests, and mine gas drainage.

[0004] While the aforementioned patents have solved the problem of water pressure embolization, they only allow water to drain from the wellhead. The embolization capsule, under the pressure of the water column from the wellhead to the plug, struggles to contract, making complete drainage and pressure relief difficult. However, due to the equipment's unique nature, the embolization filling and water pressure fracturing pathways are independent. Therefore, the filling tube needs to pass through the drill pipe before the wellhead is sealed. The filling tube pressurizes the embolization to seal the test section, while the water pressure fracturing pathway needs to reach the test formation through the drill pipe. This requires the wellhead sealing device to both pressurize the embolization through the filling tube and pressurize the test formation with water. Because the water pressure fracturing formation pressure is high, with maximum pressures exceeding 30 MPa, conventional sealing methods are insufficient to guarantee a proper seal when sealing the filling tube, leading to inaccurate test results and irreparable damage to underground engineering projects.

[0005] Therefore, there is a need for an adjustable pressure bladder-type hydraulic fracturing orifice sealer. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned problems and provide an adjustable pressure bladder-type hydraulic fracturing orifice sealer.

[0007] To achieve the above-mentioned technical objectives and effects, the present invention is implemented through the following technical solution:

[0008] This invention provides an adjustable pressure liquid bladder type hydraulic fracturing orifice sealer, comprising a housing, inside which two upper gaskets and two lower gaskets are arranged opposite each other, and a high-pressure filling tube is disposed between the two upper gaskets and two lower gaskets. A liquid bladder is disposed on each of the lower gaskets, and the liquid bladder has a central channel inside, with the high-pressure filling tube disposed inside the central channel. The liquid bladder has a filling cavity inside, and the housing has a liquid bladder storage cavity in the middle, which is used to fill and expand with liquid. Under the action of expansion pressure, the liquid bladder abuts against the high-pressure filling tube and the expanding and filling liquid bladder storage cavity, thereby achieving a sealing effect.

[0009] The aforementioned adjustable pressure bladder type hydraulic fracturing orifice sealer has a drill rod connecting thread at the lower part of the housing for connecting with a drill rod, a central channel inside the housing for a high-pressure filling tube to pass through, and a liquid bladder storage cavity for providing assembly space for the liquid bladder.

[0010] The aforementioned adjustable pressure bladder-type hydraulic fracturing orifice sealer has a limiting plate on the upper part of the housing, which restricts the position of the upper gasket.

[0011] The aforementioned adjustable pressure bladder-type hydraulic fracturing orifice sealer has a high-pressure water channel on the lower side of the housing. The high-pressure water channel can inject high-pressure water into the hole through the central channel and drill rod for test operations. The side of the liquid bladder storage cavity of the housing has a through hole for passing through the liquid filling connector on the liquid bladder.

[0012] The aforementioned adjustable pressure bladder-type hydraulic fracturing orifice sealer has a pressure cap connected to an internal thread on the upper part of the housing, and the upper gasket is connected to the pressure cap. The pressure cap is connected to the pressure cap via a threaded connection.

[0013] In the aforementioned adjustable pressure bladder type hydraulic fracturing orifice sealer, the lower gasket and the upper gasket have the same structure, the only difference being their arrangement positions: one is located above the bladder, and the other is located below the bladder.

[0014] The aforementioned adjustable pressure bladder-type hydraulic fracturing orifice sealer has a lower gasket with a semi-circular structure and a central hole inside. Two lower gaskets are horizontally combined, forming a circular hole at their center to allow the passage of a high-pressure filling tube. The diameter of the circular hole is larger than the diameter of the high-pressure filling tube. The main function of the lower and upper gaskets is to restrict the expansion shape of the bladder and prevent the bladder from deforming and breaking due to excessive expansion caused by excessive pressure.

[0015] The aforementioned adjustable pressure bladder type hydraulic fracturing orifice sealer has a valve connected to the side of the bladder, a filling connector provided on the side of the bladder, a filling channel provided in the middle of the filling connector, and a connecting thread provided at the top for connecting the valve. The valve can control the bladder to expand under pressure or contract under pressure.

[0016] The aforementioned adjustable pressure bladder-type hydraulic fracturing orifice sealer has a central channel in the middle of the gland for passing through a high-pressure filling tube. The lower part of the gland has an external thread for engaging with the internal thread of the gland connection on the upper part of the housing. The lower part of the gland has a boss, which, under the engagement of the external thread and the internal thread of the gland connection, presses against the upper gasket, so that the upper gasket and the limiting piece are completely fitted together.

[0017] In the aforementioned adjustable pressure bladder-type hydraulic fracturing orifice sealer, the diameters of the central channels on the housing, the liquid bladder, and the pressure cap are larger than those of the high-pressure filling tube.

[0018] The beneficial effects of this invention are:

[0019] In this invention, water is injected into the liquid bladder to pressurize it. The expansion and contraction of the liquid bladder achieve the sealing of the borehole and the disassembly of the components. When the liquid bladder expands, it seals the gap between the high-pressure filling tube and the central channel of the liquid bladder, as well as the gap between the liquid bladder and the shell. When the liquid bladder contracts, the high-pressure filling tube can be removed from the central channel of each component. One liquid bladder provides two sealing effects, which facilitates disassembly and improves work efficiency. When different fracturing pressures are generated under different working conditions, different pressures can be applied to the liquid bladder to adapt to different working conditions, achieving real-time adjustable sealing under different pressures. The adjustable sealing effect can improve the engineering adaptability of the orifice sealer, improve engineering quality and efficiency.

[0020] Of course, any product implementing this invention does not necessarily need to achieve all of the above advantages at the same time. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a cross-sectional view of the overall structure of the liquid bladder of the present invention in its inflated state;

[0023] Figure 2 This is a cross-sectional structural diagram of the shell in this invention;

[0024] Figure 3This is a three-dimensional structural diagram of the lower gasket in this invention;

[0025] Figure 4 This is a cross-sectional structural diagram of the liquid bladder in this invention;

[0026] Figure 5 This is a three-dimensional structural diagram of the pressure cap in this invention;

[0027] Figure 6 This is a cross-sectional view of the overall structure of the liquid bladder in the contracted state in this invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figures 1-6 As shown, this embodiment provides an adjustable pressure liquid bladder type hydraulic fracturing orifice sealer, including a housing 1. Inside the housing 1, two upper gaskets 5 and two lower gaskets 2 are arranged opposite each other. A high-pressure filling tube 7 is disposed between the two upper gaskets 5 and the two lower gaskets 2. A liquid bladder 3 is disposed on each lower gasket 2. The liquid bladder 3 has a central channel 301 inside, and the high-pressure filling tube 7 is disposed inside the central channel 301. A liquid filling cavity 302 is disposed inside the liquid bladder 3. A liquid bladder storage cavity 103 is located in the middle of the housing 1. The liquid filling cavity 302 is used to fill and expand with liquid. Under the action of expansion pressure, it abuts against the high-pressure filling tube 7 and the expanding and filling liquid bladder storage cavity 103, thereby achieving a sealing effect.

[0030] Specifically, the lower gasket 2 and the upper gasket 5 are designed as semicircles, and the two gaskets are combined to form a complete ring, which facilitates equipment assembly. At the same time, the small-diameter central hole 201 (larger than the high-pressure filling tube, with a range of 0-3mm) can limit the expansion space of the liquid bladder 3, preventing the liquid bladder 3 from being damaged due to excessive local deformation during high-pressure expansion and deformation. The expansion and contraction of the liquid bladder 3 achieves the sealing of the borehole and the disassembly of components. When the liquid bladder 3 expands, it seals the gap between the high-pressure filling tube 7 and the central channel 301 of the liquid bladder, as well as the gap between the liquid bladder 3 and the shell 1. When the liquid bladder contracts, the high-pressure filling tube 7 can be removed from the central channel of each component. Then, the adjustable pressure liquid bladder type hydraulic fracturing borehole sealer is unscrewed as a whole, detached from the drill rod, and the drilling operation can be carried out. It should be noted that the dynamic sealing effect is achieved by utilizing the pressure difference between the expansion pressure of the liquid bladder 3 and the experimental pressure. The expansion of the liquid bladder 3 seals the gaps between the high-pressure filling pipe 7 and the central channel 301 of the liquid bladder, as well as the gap between the liquid bladder 3 and the shell 1. Dynamic sealing is achieved as long as the liquid pressure inside the liquid bladder 3 is greater than the experimental pressure. Furthermore, for different engineering test pressures, different pressures can be applied to the liquid inside the liquid bladder 3 to adapt to different working conditions, achieving real-time adjustable dynamic sealing under different pressures. The adjustable pressure sealing effect improves the engineering adaptability of the orifice sealer, enhancing engineering quality and efficiency. After pressurization, valve 4 is closed for testing. After the test, valve 4 is opened to depressurize, and then the entire adjustable pressure liquid bladder-type hydraulic fracturing orifice sealer is detached from the drill pipe for drilling operations. This process is repeated for testing different target formations, significantly improving the sealing effect and engineering efficiency.

[0031] In this invention, the lower part of the housing 1 has a drill rod connecting thread 101 for connecting with a drill rod. The housing 1 has a central channel 102 through which the high-pressure filling tube 7 passes. The liquid bladder storage cavity 103 provides assembly space for the liquid bladder 3. The upper part of the housing 1 has a limiting piece 104 that restricts the position of the upper gasket 5. The lower side of the housing 1 has a high-pressure water channel 105, through which high-pressure water can be injected into the hole via the central channel 102 and the drill rod for testing. The side of the liquid bladder storage cavity 103 has a through hole 106 for through which the filling connector 303 on the liquid bladder 3 passes.

[0032] In this embodiment, the upper part of the housing 1 has a pressure cap connecting internal thread 107, and the upper gasket 5 is connected to the pressure cap 6. The pressure cap connecting internal thread 107 is connected to the pressure cap 6 through the thread. The lower gasket 2 has the same structure as the upper gasket 5, the only difference being the arrangement position. One is located above the liquid bladder 3, and the other is located below the liquid bladder 3.

[0033] In this invention, the lower gasket 2 has a semi-circular structure with a central hole 201 inside. Two lower gaskets 2 are horizontally combined, forming a circular hole at their center for the high-pressure filling tube 7 to pass through. The diameter of the circular hole is larger than the diameter of the high-pressure filling tube 7. The main function of the lower gasket 2 and the upper gasket 5 is to restrict the expansion shape of the liquid bladder 3, preventing the liquid bladder 3 from deforming and breaking due to excessive expansion caused by excessive pressure. A valve 4 is connected to the side of the liquid bladder 3, and a filling connector 303 is provided on the side of the liquid bladder 3. A filling channel 304 is provided in the middle of the filling connector 303, and a connecting thread 305 is provided at its top for connecting the valve 4. The valve 4 can control the pressure expansion or pressure relief contraction of the liquid bladder 3.

[0034] It should be noted that the pressure expansion and pressure relief contraction of the liquid bladder 3 are controlled by valve 4. When valve 4 is opened, liquid (water) is injected into the liquid bladder 3 to pressurize it. The pressure value is set according to the working pressure (the set pressure value is greater than the target formation fracturing pressure). After the set pressure value is reached, valve 4 is closed, and the liquid bladder 3 will maintain pressure until the end of the test. After the test, valve 4 can be opened to depressurize and then disassembled. In addition, the equipment for pressurizing the liquid bladder 3 can use the same equipment as the hydraulic fracturing equipment. The pressure expansion and sealing of the hole and the hydraulic fracturing are independent of each other, which improves the utilization rate of the equipment.

[0035] It should be noted that the pressure cap 6 has a central channel 601 for the high-pressure filling tube 7 to pass through. The lower part of the pressure cap 6 has an external thread 602 for engaging with the internal thread 107 of the pressure cap connection on the upper part of the housing 1. The lower part of the pressure cap 6 has a boss 603, which, with the engagement of the external thread 602 and the internal thread 107, presses against the upper gasket 5, ensuring complete contact between the upper gasket 5 and the limiting piece 104. The diameters of the central channel 102 on the housing 1, the central channel 301 on the liquid bladder 3, and the central channel 601 on the pressure cap 6 are larger than that of the high-pressure filling tube 7. It should be noted that the diameters of the central channels 102 on the liquid bladder 3 and the pressure cap 6 are larger than that of the high-pressure filling tube 7 to avoid difficulty in passing the high-pressure filling tube 7 if the diameter is too small, and a reduced sealing effect of the liquid bladder if the diameter is too large.

[0036] The working principle of this invention is as follows:

[0037] Step 1: The drill pipe is lowered into the target test formation. Then, the high-pressure filling tube passes through the central channel 102 on the housing 1. Two lower gaskets 2 are placed on both sides of the high-pressure filling tube 7 and reach the bottom of the liquid storage chamber 103 of the housing 1. The high-pressure filling tube is then passed through the central channel 301 of the liquid bladder 3, and the filling connector 303 on the liquid bladder 3 is matched with the through hole 106 on the housing 1. Then, the upper gaskets 5 are placed on both sides of the high-pressure filling tube 7 and placed into the upper gasket limiter 10 on the housing 1. 4. Next, tighten the gland 6 onto the housing 1 using threads, and fix the position of the upper gasket 5. Then, fix the valve 4 onto the filling connector of the liquid bladder 3. Then, connect the entire adjustable pressure liquid bladder type hydraulic fracturing orifice sealer to the drill rod through the drill rod connecting thread 101 on the housing 1. (In this process, other components of the adjustable pressure liquid bladder type hydraulic fracturing orifice sealer can also be assembled before passing through the high-pressure filling tube 7. In this case, it is necessary to ensure that the diameters of the lower gasket 2 and the upper gasket 5 are larger than the diameter of the high-pressure filling tube.)

[0038] Step 2: After assembly, water is injected into the liquid bladder 3 to pressurize it. The expansion of the liquid bladder 3 seals the gaps between the high-pressure filling pipe 7 and the central channel 301 of the liquid bladder, as well as the gaps between the liquid bladder 3 and the shell 1. Different pressures can be applied to the liquid bladder 3 to adapt to different working conditions, achieving real-time adjustable sealing under different pressures. The adjustable pressure sealing effect improves the engineering adaptability of the orifice sealer, enhancing engineering quality and efficiency. After pressurization, valve 4 is closed for testing. After the test, valve 4 is opened to depressurize, and then the entire adjustable pressure liquid bladder-type hydraulic fracturing orifice sealer is detached from the drill pipe, followed by drilling operations. This process is repeated for testing different target formations.

[0039] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An adjustable pressure bladder water fracturing port closure comprising a housing (1) characterised in that, The housing (1) has two upper gaskets (5) and two lower gaskets (2) arranged opposite to each other inside. A high-pressure filling tube (7) is arranged between the two upper gaskets (5) and the two lower gaskets (2). A liquid bladder (3) is arranged on the lower gasket (2). The liquid bladder (3) has a central channel (301) inside. The high-pressure filling tube (7) is arranged inside the central channel (301). The liquid bladder (3) is provided with a liquid filling chamber (302) inside, and the housing (1) has a liquid bladder storage chamber (103) in the middle. The liquid filling chamber (302) is used to fill the liquid and expand. Under the action of expansion pressure, it abuts against the high pressure filling tube (7) and the expansion filling liquid bladder storage chamber (103) to achieve a sealing effect.

2. The adjustable pressure bladder type hydraulic fracturing orifice sealer according to claim 1, characterized in that, The lower part of the housing (1) has a drill rod connecting thread (101) for connecting with the drill rod. The housing (1) has a central channel (102) inside, through which the high-pressure filling tube (7) passes. The liquid bladder storage cavity (103) provides assembly space for the liquid bladder (3).

3. The adjustable pressure bladder type hydraulic fracturing orifice sealer according to claim 1, characterized in that, The upper part of the housing (1) has a limiting piece (104) that restricts the position of the upper gasket (5).

4. The adjustable pressure bladder type hydraulic fracturing orifice sealer according to claim 2, characterized in that, The lower side of the shell (1) has a high-pressure water channel (105). The high-pressure water channel (105) can inject high-pressure water into the hole through the central channel (102) and the drill rod for test operations. The side of the liquid bladder storage cavity (103) of the shell has a through hole (106). The through hole (106) is used to pass through the liquid filling connector (303) on the liquid bladder (3).

5. The adjustable pressure bladder type hydraulic fracturing orifice sealer according to claim 1, characterized in that, The upper part of the housing (1) has a pressure cap connecting internal thread (107), and the upper gasket (5) is connected to the pressure cap (6). The pressure cap connecting internal thread (107) is connected to the pressure cap (6) through the thread.

6. The adjustable pressure bladder type hydraulic fracturing orifice sealer according to claim 1, characterized in that, The lower pad (2) and the upper pad (5) have the same structure, the only difference being their arrangement positions. One is located above the liquid bladder (3), and the other is located below the liquid bladder (3).

7. The adjustable pressure bladder type hydraulic fracturing orifice sealer according to claim 1, characterized in that, The lower gasket (2) has a semi-circular structure with a central hole (201) inside. The two lower gaskets (2) are horizontally combined, and a circular hole is formed at the center position to allow the high-pressure filling tube (7) to pass through. The diameter of the circular hole is larger than the diameter of the high-pressure filling tube (7). The main function of the lower gasket (2) and the upper gasket (5) is to restrict the expansion shape of the liquid bladder (3) and prevent the liquid bladder (3) from deforming and breaking due to excessive expansion caused by excessive pressure.

8. The adjustable pressure bladder type hydraulic fracturing orifice sealer according to claim 1, characterized in that, The liquid bladder (3) is connected to a valve (4) on its side. The liquid bladder (3) is provided with a filling connector (303) on its side. The filling connector (303) is provided with a filling channel (304) in the middle and a connecting thread (305) at its top for connecting the valve (4). The valve (4) can control the liquid bladder (3) to expand under pressure or contract under pressure.

9. The adjustable pressure bladder type hydraulic fracturing orifice sealer according to claim 1, characterized in that, The pressure cap (6) has a central channel (601) in the middle for passing through the high-pressure filling tube (7). The pressure cap (6) has an external thread (602) at the bottom for engaging with the internal thread (107) of the pressure cap on the upper part of the housing (1). The pressure cap (6) has a boss (603) at the bottom. The boss (603) presses against the upper gasket (5) under the engagement of the external thread (602) and the internal thread (107) of the pressure cap, so that the upper gasket (5) and the limiting piece (104) are completely in contact.

10. The adjustable pressure bladder type hydraulic fracturing orifice sealer according to claim 9, characterized in that, The diameters of the central channel (102) on the housing (1), the central channel (301) on the liquid bladder (3), and the central channel (601) on the pressure cap (6) are larger than those of the high-pressure filling tube (7).

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