An improved high-temperature hot fluid injection pipe insulation coupling

Abstract

This utility model relates to the field of oil drilling and production technology, and in particular to an improved high-temperature hot fluid injection pipe insulation coupling. It includes a coupling body with an internal thread, which connects the coupling body to the oil pipe. It also includes a nano-insulating strip wound around the outer surface of the coupling body, and a protective outer tube fitted over the outer side of the coupling body. The protective outer tube is connected to the coupling body by a weld. In this utility model, by setting up a three-layer composite insulation structure consisting of the coupling body, the nano-insulating strip, and the protective outer tube, high-efficiency heat insulation is achieved under normal operating conditions. The nano-insulating strip, wound around the outer surface of the coupling body, has an extremely low thermal conductivity that effectively blocks heat conduction from the inside of the pipe to the outside, significantly reducing the temperature gradient at the coupling connection point. This avoids corrosive gas condensation and electrochemical corrosion caused by localized temperature drops, thus improving steam injection quality and thermal recovery efficiency.

Description

Technical Field

[0001] This utility model relates to the field of oil drilling and production technology, and in particular to an improved high-temperature hot fluid injection pipe insulation coupling. Background Technology

[0002] In heavy oil thermal recovery and geothermal development operations, high-temperature hot fluid injection pipes are core equipment. Production companies often pay more attention to the research on the thermal insulation performance of transmission pipelines. As a key component for connecting geothermal pipes and oil pipes, couplings are also widely used in heavy oil thermal recovery and geothermal development operations.

[0003] However, in the steam injection stage of heavy oil extraction, high-temperature, high-pressure wet saturated steam needs to be rapidly injected into the oil layer. The injection volume is large and the duration is long, which places high demands on the durability of the steam injection tubing and its couplings. Taking Northeast China as an example, the average temperature of the steam injected in heavy oil thermal recovery is about 320℃, and in some well areas it exceeds 350℃, with pressures reaching 12~17. At high temperatures and pressures, significant heat conduction and radiation are easily generated at the coupling joints during steam injection, leading to substantial heat loss. Simultaneously, heavy components in heavy oil undergo thermal cracking under high temperature and pressure, generating corrosive gases such as CO2 and H2S. During steam transportation, the temperature at the coupling drops, causing corrosion, thinning, slippage, and perforation, which may lead to leaks or even explosions, seriously threatening the integrity and safety of the equipment. Therefore, this application aims to address the high requirements for couplings during the steam injection stage of heavy oil thermal recovery, as well as the problems caused by heat conduction, radiation, and corrosive gases at high temperatures, leading to temperature drops, corrosion, thinning, slippage, and perforation, which may cause leaks or explosions and threaten the integrity and safety of the equipment. An improved high-temperature hot fluid injection pipe insulation coupling is proposed. Utility Model Content

[0004] To overcome the challenges of injecting large volumes of high-temperature, high-pressure, wet saturated steam into the oil reservoir during the heavy oil extraction stage, which places high demands on the durability of tubing and couplings, taking Northeast China as an example, the steam injection temperature is approximately 320~350℃ and the pressure is 12~17 MPa. Under high temperature, significant heat conduction and radiation occur at the couplings. At the same time, the thermal cracking of heavy components generates corrosive gases such as CO2 and H2S, causing a temperature drop at the couplings, leading to corrosion thinning, stripping, perforation, and other damage, which may cause leakage or explosion, seriously threatening the integrity and safety of the equipment.

[0005] The technical solution of this utility model is as follows: an improved high-temperature hot fluid injection pipe insulation coupling, including a coupling body, an internal thread inside the coupling body, the coupling body being connected to the oil pipe through the internal thread, and a nano heat insulation strip wound on the outer surface of the coupling body. A protective outer tube is fitted on the outer side of the coupling body, and the protective outer tube is connected to the coupling body through a weld.

[0006] Preferably, the coupling body has a piston cavity, a piston ring is slidably connected in the piston cavity, and one end of the piston ring is connected to a plurality of connecting rods arranged in a circular shape, and a compression wedge is connected to the connecting rod.

[0007] Preferably, both ends of the coupling body are provided with a plurality of second winding grooves, and both ends of the protective outer tube are provided with a plurality of first winding grooves, with the first winding grooves corresponding to the second winding grooves one by one.

[0008] Preferably, the piston cavity has several fixed through holes arranged in a circular shape, the piston cavity is connected to the inner cavity of the coupling body through the fixed through holes, and both ends of the coupling body have flow grooves, the second winding groove is connected to the piston cavity through the flow grooves.

[0009] Preferably, a number of self-locking blocks arranged in a circular pattern are connected to one end face of the piston ring. The self-locking blocks and the compression wedges are arranged in an alternating manner. A self-locking groove is opened on the inner surface of the protective outer tube. When the piston ring moves to the fixed through hole, the self-locking blocks are locked in the self-locking groove.

[0010] Preferably, the piston cavity has a pre-cut groove in the middle section, a cutting ring is sleeved inside the pre-cut groove, and a plurality of piercing blades arranged in a circular shape are fixed on the inner ring of the cutting ring.

[0011] Preferably, both ends of the protective outer tube are provided with welded A slope, and both ends of the coupling body are provided with welded B slope.

[0012] The beneficial effects of this utility model are: 1. This utility model achieves high-efficiency heat insulation under normal operating conditions by setting a three-layer composite insulation structure consisting of a coupling body, a nano-insulation strip, and a protective outer tube. The nano-insulation strip is wrapped around the outer surface of the coupling body. Its extremely low thermal conductivity can effectively block the heat conducted from the inside of the tube to the outside, significantly reducing the temperature gradient at the coupling connection. This avoids corrosive gas condensation and electrochemical corrosion caused by local temperature drop, improving the quality of steam injection and thermal recovery efficiency. At the same time, the protective outer tube is connected to the coupling body by a weld, which not only provides mechanical protection for the nano-insulation strip, preventing it from being scratched and damaged during well running and operation, but also ensures the structural integrity of the entire device in the high-pressure environment downhole. This gives the coupling both excellent heat insulation performance and long-term service reliability, reducing energy waste and carbon emissions caused by heat dissipation from the source. 2. This utility model introduces high-pressure fluid from inside the coupling body into the upper chamber of the piston chamber through a fixed through hole. The flow groove transmits the annular pressure inside the nano-insulation strip to the lower chamber of the piston chamber through the second winding groove. During normal operation, the pressure in the two chambers is balanced and the piston ring remains stationary. Once the coupling body is corroded and perforated, high-pressure steam or corrosive gas will rush into the nano-insulation strip instantly, causing the pressure in the lower chamber to rise sharply. The thrust drives the piston ring to move, and then the axial thrust is converted into radial inward extrusion force through the connecting rod and the extrusion wedge, forcing the cut-off ring to cut into the coupling along the pre-cut groove, cutting off the fluid passage, so as to prevent serious accidents such as blowouts, explosions and toxic media leaks caused by coupling perforation. 3. This utility model, through the cooperation of the self-locking block and the self-locking groove, ensures that the emergency cut-off mechanism is locked in the sealing position after being triggered. The self-locking block is integrally connected to the side end face of the piston ring and is arranged alternately with the extrusion wedge along the circumferential edge. When the piston ring moves to the cut-off completion position under the drive of fluid pressure difference, the self-locking block is precisely engaged in the self-locking groove preset on the inner surface of the protective outer tube, forming a multi-tooth ratchet mechanical lock. The engagement is achieved by utilizing the elastic deformation of the structure. Once in the groove, the piston ring cannot be moved back, and the cut-off ring and piercing blade are embedded inside the coupling and bite the end of the tubing, forming an irreversible metal sealing barrier. This allows maintenance personnel to intuitively determine which coupling has been cut off by observing the pop-out state of the self-locking block, greatly shortening the fault location investigation time and improving well workover efficiency. Attached Figure Description

[0013] Figure 1 The diagram shown is a three-dimensional structural schematic of the thermal insulation coupling of this utility model. Figure 2 The diagram shown is a three-dimensional structural schematic of the main body of the thermal insulation coupling of this utility model. Figure 3 The diagram shown is a cross-sectional view of the protective outer tube of the thermal insulation coupling of this utility model. Figure 4 The diagram shown is a three-dimensional structural schematic of the piston ring of the thermal insulation coupling of this utility model. Figure 5 The diagram shown is a cross-sectional view of the cut-off ring of the thermal insulation coupling of this utility model. Figure 6 The diagram shown illustrates the use of the thermal insulation coupling of this utility model.

[0014] Explanation of reference numerals in the attached drawings: 1. Protective outer tube; 2. Weld seam; 4. Nano heat insulation strip; 301. Coupling body; 302. Internal thread; 501. Welding slope A; 502. First winding groove; 503. Welding slope B; 504. Second winding groove; 601. Piston chamber; 602. Flow groove; 603. Fixed through hole; 604. Piston ring; 605. Connecting rod; 606. Extrusion wedge; 607. Self-locking block; 608. Self-locking groove; 701. Pre-cut groove; 702. Cut-off ring; 703. Piercing blade. Detailed Implementation

[0015] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0016] Example 1: refer to Figures 1-2 The structure shown is an improved high-temperature hot fluid injection pipe insulation coupling, including a coupling body 301, with an internal thread 302 inside the coupling body 301. The coupling body 301 is connected to the oil pipe through the internal thread 302. It also includes a nano heat insulation strip 4 wound on the outer surface of the coupling body 301. A protective outer tube 1 is sleeved on the outside of the coupling body 301. The protective outer tube 1 is connected to the coupling body 301 through a weld 2.

[0017] The wound nano-insulation strip 4 covers the outer cylindrical surface of the coupling body 301 through multi-layer winding, thereby establishing a high thermal resistance barrier between the coupling body 301 and the protective outer tube 1. The ultra-low thermal conductivity of the nanomaterial effectively locks the heat of the fluid inside the coupling within the tube, so that the coupling connection can maintain a high wall temperature under long-term high-temperature steam injection conditions. This inhibits the condensation of corrosive gases such as CO2 and H2S and electrochemical corrosion induced by a sharp drop in temperature, fundamentally reducing the risk of corrosion thinning and perforation. The protective outer tube 1 is sleeved on the outside of the nano-insulation strip 4 to resist downhole high pressure, corrosive fluids and mechanical scraping during the running of the tubing, protecting the internal insulation material from damage during well entry, setting and long-term production. At the same time, it is connected to the coupling body 301 through the weld 2 to form an integral load-bearing component, enhancing the coupling area's resistance to bending, tension and vibration.

[0018] according to Figures 3-4 As shown, both ends of the protective outer tube 1 are provided with welding slope A 501, and both ends of the coupling body 301 are provided with welding slope B 503.

[0019] Among them, welding slope A 501 and welding slope B 503 are respectively processed on the joint surfaces of the protective outer pipe 1 and the coupling body 301 at both ends. The two cooperate with each other to form a complete welding interface, providing sufficient space for deposited metal and reasonable bevel angle for weld 2, ensuring full cross-section penetration during welding, avoiding welding defects such as incomplete penetration or slag inclusion, so that weld 2 still has strength comparable to the base material under extreme high temperature and high pressure environment, and can withstand internal pressure of more than 17 MPa and axial load of the tubing string. At the same time, it prevents annular leakage caused by weld defects, completely isolates the working space of nano heat insulation strip 4 from the external downhole fluid, and ensures the long-term sealing and long-term service reliability of the insulation structure.

[0020] Example 2: Based on the above embodiment 1, in order to solve the problem that if the coupling body 301 is corroded and perforated, causing high-temperature and high-pressure fluid to be ejected through the annulus of the insulation layer, which may lead to major accidents such as well blowouts and leaks of toxic and harmful gases, reference is made to... Figure 4 The structure shown; Unlike Embodiment 1, the coupling body 301 has a piston cavity 601, a piston ring 604 is slidably connected in the piston cavity 601, and a number of connecting rods 605 arranged in a circular shape are connected to one end of the piston ring 604. A compression wedge 606 is connected to the connecting rod 605.

[0021] The piston chamber 601 is machined between the outer wall of the coupling body 301 and the protective outer tube 1 to form an annular cylindrical chamber. The piston ring 604 moves axially with low friction inside the chamber, thereby dividing the piston chamber 601 into two independent pressure chambers, upper and lower, which respectively sense the fluid pressure inside the coupling and the annular pressure inside the nano-insulation strip 4. The connecting rod 605 rigidly connects the piston ring 604 and the extrusion wedge 606, so that the axial displacement of the piston ring 604 is converted into the same direction movement of the extrusion wedge 606 without delay. The multiple circumferentially distributed connecting rods 605 ensure uniform force transmission and avoid the problem of off-center load jamming.

[0022] according to Figures 3-4 As shown, both ends of the coupling body 301 are provided with several second winding grooves 504, and both ends of the protective outer tube 1 are provided with several first winding grooves 502. The first winding grooves 502 correspond one-to-one with the second winding grooves 504.

[0023] Among them, the first winding groove 502 and the second winding groove 504 are located in the nano-insulation strip 4 filling area at both ends of the protective outer tube 1 and the coupling body 301. They provide clear axial start and end point limits when winding the nano-insulation strip 4, so that the multi-layer nano-insulation strip 4 can be neatly and densely wound and fixed in layers, preventing it from axially shifting, accumulating or loosening during repeated thermal expansion and contraction or vibration. This ensures that the thickness and density of the insulation layer are uniform in the circumferential direction, avoiding the formation of thermal bridges or local hot spots, thereby maintaining the preset thermal insulation performance for a long time.

[0024] according to Figure 4 As shown, the piston cavity 601 has several fixed through holes 603 arranged in a circular shape. The piston cavity 601 is connected to the inner cavity of the coupling body 301 through the fixed through holes 603. Both ends of the coupling body 301 are provided with flow grooves 602. The second winding groove 504 is connected to the piston cavity 601 through the flow grooves 602.

[0025] The fixed through hole 603 serves as a high-pressure tapping channel, continuously and unobstructedly introducing the high-temperature and high-pressure steam or corrosive fluid pressure inside the coupling into the upper end face of the piston ring 604, providing a persistent and stable power source for the trigger cut-off assembly. The flow groove 602 is opened in the shoulders at both ends of the coupling body 301, with one end connected to the area of ​​the second winding groove 504 of the nano-insulation strip 4, and the other end connected to the lower cavity of the piston chamber 601. This immediately transmits any pressure fluctuation caused by leakage due to perforation of the body at any point within the entire nano-insulation strip 4 coverage area to the lower end face of the piston ring 604, thereby ensuring the long-term sensitivity and operational reliability of the entire machine.

[0026] according to Figure 5 As shown, a pre-cutting groove 701 is provided in the middle section of the piston cavity 601, and a cutting ring 702 is sleeved inside the pre-cutting groove 701. Several piercing blades 703 arranged in a circular shape are fixed on the inner ring of the cutting ring 702.

[0027] The pre-cut groove 701 enables the cutting ring 702 to accurately cut into the inner cavity along a preset path when subjected to radial extrusion force. This not only avoids damaging the normal threaded connection area of ​​the coupling body 301, but also significantly reduces the force required for cutting. When the extrusion wedge 606 is pushed forward, the cutting ring 702 retracts inward, and the piercing blade 703 cuts the remaining wall thickness along the pre-cut groove 701 like a pipe cutter wheel blade, and continues to embed into the end of the oil pipe inside the coupling to block the high-temperature and high-pressure fluid channel.

[0028] Example 3: Based on the above-described embodiment 2, in order to address the problem of preventing the cut-off ring 702 from resetting due to downhole pressure fluctuations, water hammer, or subsequent construction vibrations after the emergency cut-off mechanism is accidentally triggered, thereby causing the cut-off seal to fail, reference is made to... Figure 4 The structure shown; Unlike Embodiment 2, a number of self-locking blocks 607 arranged in a circular pattern are connected to one end face of the piston ring 604. The self-locking blocks 607 and the compression wedges 606 are arranged in an alternating manner. A self-locking groove 608 is provided on the inner surface of the protective outer tube 1. When the piston ring 604 moves to the fixed through hole 603, the self-locking blocks 607 are engaged in the self-locking groove 608.

[0029] The self-locking block 607 is a flexible metal protrusion integrally formed on the corresponding end face of the piston ring 604. After being triggered, it moves to the cut-off position along with the piston ring 604. At this time, the claw of the self-locking block 607 slides into the self-locking groove 608 pre-machined on the inner wall of the protective outer tube 1, forming a one-way lock. The self-locking block 607 and the extrusion wedge 606 are arranged alternately on the circumference, which not only avoids positional interference between the two during movement, but also makes the driving force and locking force around the piston ring 604 evenly distributed, preventing the piston ring 604 from tilting or jamming. The self-locking groove 608 is an annular groove that matches the shape of the end of the self-locking block 607. Maintenance personnel can quickly locate the coupling that has been perforated and has cut off by observing whether the self-locking block 607 pops out, which greatly reduces the troubleshooting time.

[0030] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An improved high-temperature hot-fluid injection pipe insulation coupling, comprising a coupling body (301), an internal thread (302) is formed in the coupling body (301), and the coupling body (301) is connected with a tubing through the internal thread (302), characterized in that: It also includes a nano heat insulation strip (4) wrapped around the outer surface of the coupling body (301). A protective outer tube (1) is sleeved on the outer side of the coupling body (301). The protective outer tube (1) is connected to the coupling body (301) through a weld (2). A piston cavity (601) is opened on the coupling body (301). A piston ring (604) is slidably connected in the piston cavity (601). One end of the piston ring (604) is connected to a number of connecting rods (605) arranged in a circular shape. A compression wedge (606) is connected to the connecting rod (605).

2. The improved high-temperature hot-fluid injection pipe insulation coupling according to claim 1, characterized in that: Both ends of the coupling body (301) are provided with several second winding grooves (504), and both ends of the protective outer tube (1) are provided with several first winding grooves (502). The first winding grooves (502) and the second winding grooves (504) correspond one-to-one.

3. The improved high-temperature hot-fluid injection pipe insulation coupling of claim 2, wherein: The piston cavity (601) is provided with a plurality of fixed through holes (603) arranged in a circular shape. The piston cavity (601) is connected to the inner cavity of the coupling body (301) through the fixed through holes (603). Both ends of the coupling body (301) are provided with flow grooves (602). The second winding groove (504) is connected to the piston cavity (601) through the flow grooves (602).

4. The improved high-temperature hot-fluid injection pipe insulation coupling of claim 3, wherein: A number of self-locking blocks (607) arranged in a circular pattern are connected to one end face of the piston ring (604). The self-locking blocks (607) and the compression wedges (606) are arranged in an alternating manner. A self-locking groove (608) is provided on the inner surface of the protective outer tube (1). When the piston ring (604) moves to the fixed through hole (603), the self-locking blocks (607) are locked in the self-locking groove (608).

5. The improved high-temperature hot-fluid injection pipe insulation coupling of claim 1, wherein: The piston chamber (601) has a pre-cut groove (701) in the middle section, and a cutting ring (702) is sleeved inside the pre-cut groove (701). Several piercing blades (703) arranged in a circular shape are fixed on the inner ring of the cutting ring (702).

6. The improved high-temperature hot-fluid injection pipe insulation coupling of claim 1, wherein: The protective outer tube (1) has welding slope A (501) at both ends, and the coupling body (301) has welding slope B (503) at both ends.

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