Composite heat preservation oil pipe

Abstract

The invention relates to the technical field of heat preservation oil pipe structures, in particular to a composite heat preservation oil pipe which comprises an oil pipe fitting and end connector pipe fittings connected to the two ends of the oil pipe fitting, the oil pipe fitting further comprises an inner working pipe, and the surface of the inner working pipe is covered with an ultra-thin metal foil layer used for reflecting heat. A vacuum layer set is arranged on the outer side of the inner working pipe ultra-thin metal foil layer and comprises a vacuum pipe sleeve internally provided with a vacuum heat insulation cavity, an outer adhesive layer is arranged on the outer side of the vacuum pipe sleeve, and supporting rings are installed at the positions, in butt joint with the end connector pipe fittings, of the left side and the right side of the vacuum pipe sleeve in an embedded mode through annular grooves. The ultrathin metal foil layer is arranged on the outer side of the inner working pipe and is combined with the vacuum layer set, a multi-layer heat reflection and vacuum heat insulation barrier is formed, heat radiation, conduction and convection losses are remarkably reduced, the fluid temperature is effectively maintained, wax precipitation or solidification caused by temperature reduction in the conveying process of high pour-point oil, thick oil and the like is prevented, and the service life of the high pour-point oil and the thick oil is prolonged. And the efficiency and the safety of oil field production are improved.

Description

Technical Field

[0001] This invention relates to the field of thermal insulation oil pipe structure technology, and in particular to a composite thermal insulation oil pipe. Background Technology

[0002] During oilfield extraction, especially in the lifting of high-pour-point and high-wax-content reservoirs and the transportation of heavy oil, the fluid temperature in wellbore and surface pipelines gradually decreases as heat is lost from the formation. Once the fluid temperature drops below the wax precipitation point or solidification point, problems such as paraffin precipitation, asphaltene deposition, and a sharp decrease in fluidity occur, leading to blockages in oil pipes and surface pipelines, severely impacting normal oilfield production and economic benefits.

[0003] Traditional insulated pipes generally employ simple single-layer vacuum jackets or single insulation materials, such as rock wool or aluminum silicate fiber filling. These types of pipes suffer from the following drawbacks: Under high pressure, corrosion, and mechanical vibration conditions downhole, single-layer vacuum jackets are highly susceptible to micro-leakage at the welds and pipe body, leading to vacuum failure and a sharp decline in insulation performance. Traditional support structures, such as metal support rings directly connecting the inner and outer pipes, create efficient heat conduction paths, causing significant heat loss through the support components and severely weakening the overall insulation effect. Therefore, a composite insulated pipe is needed to address these issues. Summary of the Invention

[0004] The purpose of this invention is to solve the problems mentioned in the background section.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A composite insulated oil pipe includes an oil pipe fitting and end fittings connected to both ends of the oil pipe fitting. The oil pipe fitting further includes... The inner working tube is covered with an ultra-thin metal foil layer for heat reflection. A vacuum layer assembly is provided on the outside of the ultra-thin metal foil layer of the inner working tube. The vacuum layer assembly includes a vacuum tube sleeve containing a vacuum insulation cavity inside. An external adhesive layer is provided on the outside of the vacuum tube sleeve. Support rings are installed in the annular grooves at the joints between the left and right sides of the vacuum tube sleeve and the end connectors. The multiple layers of ultra-thin metal foil and grid gaskets on the outside of the inner working tube are alternately wound to further optimize the heat reflection efficiency and form gradient insulation. The vacuum layer assembly is spirally woven to enhance the integrity and flexibility of the structure and adapt to the bending and vibration of the tubing downhole. The metal foil layer reflects the heat radiated outward from the inner working tube back layer by layer, reducing heat loss; the high-temperature resistant mesh gasket provides structural support and thermal stability, preventing the metal foil layer from deforming or being damaged at high temperatures. It also blocks heat conduction and convection through the high vacuum environment, improving thermal insulation performance. An outer adhesive layer is applied to the outside of the vacuum tube sleeve to enhance the adhesion and sealing between the vacuum tube sleeve and the inner and outer layers, preventing media penetration; the support ring groove is embedded at both ends of the vacuum tube sleeve and is made of polyimide composite material with high strength and low thermal conductivity. It is used to support the spatial stability of the vacuum insulation cavity while minimizing the thermal bridging effect and preventing heat loss through the support components. The protective layer includes an oil-specific outer tube disposed on the surface of the outer adhesive layer. The outer surface of the oil-specific outer tube is surrounded and covered with a scale plate, which is composed of multiple L-shaped sheet plates stacked in sequence to form a flexible protection, allowing the oil tube to deform without breaking when bent or vibrated, thereby improving mechanical impact resistance and durability.

[0006] The outer insulation layer includes a rubber outer tube covering the surface of the scale plate, and the surface of the rubber outer tube is provided with spring ribs. The rubber outer tube covering the surface of the scale plate provides additional insulation and waterproof protection.

[0007] Preferably, the surface of the outer adhesive layer is provided with a braided steel wire layer, and the braided steel wire layer is spirally braided. The spirally interwoven structure of the braided steel wire layer can evenly distribute and withstand the pressure from the outside and inside, effectively preventing the vacuum tube sleeve from becoming unstable, dented or deformed due to the pressure difference between the inside and outside, and ensuring the structural integrity and long-term stability of the vacuum insulation cavity.

[0008] Preferably, the support ring is ring-shaped and supports the vacuum insulation cavity space of the vacuum tube sleeve. The support ring is made of polyimide composite material with high strength and low thermal conductivity. As a spacer, the support ring withstands the inward compression of the external protective layer and formation pressure, as well as the possible negative pressure inside, effectively preventing the collapse or deformation of the vacuum tube sleeve and ensuring the long-term structural integrity and constant insulation space of the vacuum insulation cavity in the complex mechanical environment downhole.

[0009] Preferably, the scale plate is composed of multiple sheet-like plates stacked sequentially, and the vertical cross-section of the sheet-like plates of the scale plate has an L-shaped structure. The L-shaped vertical cross-section structure of the scale plate improves the coverage density and protective effect, preventing external objects from piercing it.

[0010] Preferably, the surface of the rubber outer tube is provided with a spiral groove adapted to the spring rib. The spring rib is embedded and filled into the spiral groove of the rubber outer tube and covered with the same material and heat-sealed. The rubber outer tube and spring rib of the outer insulation layer further isolate the external cold source and enhance the overall insulation performance and structural toughness.

[0011] Preferably, the end connector includes a connecting pipe that mates with the end of the oil pipe fitting. An external pipe end is connected to the right side of the connecting pipe. The connecting pipe is used to connect the oil pipe fitting to an external pipeline to ensure smooth fluid transmission. A reinforcing ring is provided on the left end surface of the connecting pipe to enhance the mechanical strength of the connection.

[0012] Preferably, the right side of the inner wall of the outer pipe end is provided with an internal thread groove, the left side of the internal thread groove of the outer pipe end is inclined, and an inner rubber ring is provided on the side where the internal thread groove of the outer pipe end connects with the inclined surface. The inner rubber ring is located on the side where the internal thread groove connects with the inclined surface to provide an elastic seal and prevent leakage.

[0013] Preferably, a reinforcing ring is provided on the left end surface of the connecting pipe. The connection between the connecting pipe, the reinforcing ring and the oil pipe fitting adopts a two-stage sealing structure with laser sealing as the main method and special adhesive sealing as the auxiliary method. The two-stage sealing structure with laser sealing as the main method and special adhesive sealing as the auxiliary method ensures the airtightness and reliability of the end connection and is suitable for high-pressure environments.

[0014] Preferably, the inner wall of the vacuum tube sleeve is provided with a non-evaporable getter, which can continuously adsorb gas molecules generated by material release or micro-leakage, thereby automatically maintaining a high vacuum in the interlayer. The non-evaporable getter introduced in this invention can actively and continuously adsorb these gas molecules, which is equivalent to equipping the vacuum layer with a "maintenance system", effectively compensating for the impact of micro-leakage and release, thereby automatically maintaining a high vacuum in the interlayer, ensuring the long-term stability of the insulation effect, fundamentally preventing performance failures caused by slow deterioration of vacuum, and changing the effective service life of the oil pipe from a passive state that theoretically depends on zero leakage to an active state guaranteed by the life of the getter. The presence of the non-evaporable getter can adsorb residual gas that was not completely pumped out during the manufacturing process and gas released by the material during the initial operation, which is equivalent to providing fault tolerance for the manufacturing process.

[0015] This invention has at least the following beneficial effects: 1. This invention combines an ultra-thin metal foil layer with a vacuum layer on the outside of the inner working pipe to form a multi-layer heat reflection and vacuum insulation barrier, which significantly reduces heat radiation, conduction and convection losses, effectively maintains fluid temperature, and prevents high-pour-point oil and heavy oil from waxing or solidifying due to temperature drop during transportation, thereby improving the efficiency and safety of oilfield production.

[0016] 2. This device uses a polyimide composite support ring with low thermal conductivity, which reduces the thermal bridging effect. At the same time, the scale plates in the protective layer and the rubber outer sleeve and spring rib structure of the outer insulation layer enhance the mechanical strength, corrosion resistance and vibration resistance of the tubing, enabling the tubing to adapt to harsh environments such as downhole high pressure, corrosion and mechanical vibration, extending its service life and reducing maintenance costs.

[0017] 3. The non-evaporable getter installed inside the vacuum jacket of this device can continuously adsorb gas molecules generated by material release or micro-leakage, automatically maintaining the high vacuum level of the vacuum layer. This avoids the decrease in thermal insulation performance caused by leakage in traditional vacuum jackets, ensuring the durability and reliability of the thermal insulation effect. It is especially suitable for long-term oilfield mining scenarios. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the external structure of a composite heat-insulating oil pipe proposed in this invention; Figure 2 This is a three-dimensional disassembly diagram of a composite thermal insulation oil pipe proposed in this invention; Figure 3 This is a three-dimensional disassembly diagram of the vacuum layer assembly in a composite thermal insulation oil pipe proposed in this invention; Figure 4 This is a partial disassembly diagram of the outer insulation layer in a composite insulated oil pipe proposed in this invention; Figure 5 This is a partial three-dimensional bottom view of the protective layer in a composite insulated oil pipe proposed in this invention; Figure 6 For the present invention Figure 5 Enlarged structural diagram of A in the middle; Figure 7 This is a three-dimensional disassembly diagram of the end joint pipe fitting of a composite heat-insulating oil pipe proposed in this invention.

[0020] In the picture: 1. Oil pipe fittings; 11. Inner working pipe; 12. Vacuum layer assembly; 121. Vacuum sleeve; 122. Outer rubber layer; 123. Support ring; 124. Braided steel wire layer; 13. Protective layer; 131. Oil-specific outer pipe; 132. Scale plate; 14. Outer insulation layer; 141. Rubber outer sleeve; 142. Spring reinforcement; 2. End fittings; 21. Connecting pipe; 22. Reinforcing ring; 23. External pipe end; 24. Inner rubber ring. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] Reference Figure 1-7 A composite insulated oil pipe includes an oil pipe fitting 1 and end connector fittings 2 connected to both ends of the oil pipe fitting 1. The oil pipe fitting 1 also includes... The inner working tube 11 is covered with an ultra-thin metal foil layer for reflecting heat. A vacuum layer group 12 is provided on the outside of the ultra-thin metal foil layer of the inner working tube 11. The vacuum layer group 12 includes a vacuum tube sleeve 121 containing a vacuum insulation cavity inside. An external adhesive layer 122 is provided on the outside of the vacuum tube sleeve 121. Support rings 123 are installed in the annular groove at the joints between the left and right sides of the vacuum tube sleeve 121 and the end connector pipe fitting 2. The protective layer 13 includes an oil-specific outer tube 131 disposed on the surface of the outer adhesive layer 122, and the outer surface of the oil-specific outer tube 131 is surrounded and covered with a scale plate 132. The outer insulation layer 14 includes a rubber outer sleeve 141 covering the surface of the scale plate 132, and the surface of the rubber outer sleeve 141 is provided with spring ribs 142.

[0023] The surface of the outer adhesive layer 122 is provided with a braided steel wire layer 124, and the braided steel wire layer 124 is arranged in a spiral braid.

[0024] The support ring 123 is ring-shaped and supports the vacuum insulation cavity space of the vacuum tube sleeve 121. The support ring 123 is made of polyimide composite material with high strength and low thermal conductivity.

[0025] The scale plate 132 is composed of multiple sheet-like plates stacked sequentially, and the vertical cross-section of the sheet-like plates of the scale plate 132 has an L-shaped structure.

[0026] The surface of the rubber outer tube 141 is provided with a spiral groove that is compatible with the spring rib 142. The spring rib 142 is embedded and filled into the spiral groove of the rubber outer tube 141 and then covered with the same material and heat-sealed.

[0027] The end fitting 2 includes a connecting pipe 21 that is mated to the end of the oil pipe fitting 1, and an external pipe end 23 is connected to the right side of the connecting pipe 21.

[0028] An internal thread groove is provided on the right side of the inner wall of the outer pipe end 23. The left side of the internal thread groove of the outer pipe end 23 is designed to be inclined. An inner rubber ring 24 is provided on the side where the internal thread groove of the outer pipe end 23 connects with the inclined surface.

[0029] A reinforcing ring 22 is provided on the left side surface of the connecting pipe 21. The connection between the connecting pipe 21, the reinforcing ring 22 and the oil pipe fitting 1 adopts a two-stage sealing structure with laser sealing as the main method and special adhesive sealing as the auxiliary method.

[0030] The inner wall of the vacuum sleeve 121 is provided with a non-evaporable getter, which can continuously adsorb gas molecules generated by material release or micro-leakage, thereby automatically maintaining a high vacuum in the interlayer.

[0031] The outer side of the inner working tube 11 is alternately wrapped with multiple layers of ultra-thin metal foil and a grid liner, which further optimizes the heat reflection efficiency and forms a gradient insulation. The vacuum layer group 12 is spirally woven, which enhances the integrity and flexibility of the structure and adapts to the bending and vibration of the tubing downhole. The metal foil layer reflects the heat radiated outward from the inner working tube 11 back layer by layer, reducing heat loss. The high-temperature resistant grid liner provides structural support and thermal stability, prevents the metal foil layer from deforming or being damaged at high temperatures, and blocks heat conduction and convection through the high vacuum environment, thereby improving the insulation performance. The outer adhesive layer 122 is applied to the outside of the vacuum tube sleeve 121 to enhance the adhesion and sealing between the vacuum tube sleeve 121 and the inner and outer layers, preventing media penetration. The support ring 123 is embedded in the annular groove at both ends of the vacuum tube sleeve 121. It is made of polyimide composite material, which has high strength and low thermal conductivity. It is used to support the spatial stability of the vacuum insulation cavity, while minimizing the thermal bridging effect and preventing heat loss through the support components.

[0032] The oil-specific outer tubing 131 is made of oil-resistant and corrosion-resistant materials, protecting the internal structure from downhole chemical corrosion. A scale plate 132 surrounds the surface of the oil-specific outer tubing 131, consisting of multiple L-shaped plates stacked sequentially to form a flexible protection, allowing the tubing to deform without breaking during bending or vibration, thus improving mechanical impact resistance and durability. A rubber outer sleeve 141 covers the surface of the scale plate 132, providing additional thermal insulation and waterproof protection. Spring ribs 142 are embedded and filled into the spiral grooves of the rubber outer sleeve 141, and are sealed with the same material through heat fusion, enhancing the tubing's compressive and tensile strength while maintaining a smooth surface for easy installation and maintenance.

[0033] The spirally interwoven structure of the braided steel wire layer 124 can evenly distribute and withstand pressure from both the outside and inside, effectively preventing the vacuum sleeve 121 from becoming unstable, dented, or deformed due to internal and external pressure differences. This ensures the structural integrity and long-term stability of the vacuum insulation cavity. The unique braided configuration gives this layer good flexibility, making it less prone to structural damage when the tubing equipment is subjected to bending and torsional loads during winding, laying, and complex downhole conditions. At the same time, it significantly improves its fatigue resistance to mechanical vibration and pressure cycle shock. While providing necessary constraints, the mesh-like characteristics of this layer structure avoid the formation of continuous thermal bridges, minimizing axial heat conduction through this layer and ensuring excellent and long-lasting overall insulation performance of the tubing.

[0034] The support ring 123, acting as a spacer, withstands the inward pressure from the external protective layer 13 and formation pressure, as well as potential internal negative pressure. This effectively prevents the collapse or deformation of the vacuum sleeve 121, ensuring the long-term structural integrity and constant insulation space of the vacuum insulation cavity under complex downhole mechanical environments. The invention utilizes a polyimide composite material, whose extremely low thermal conductivity inherently hinders heat transfer axially through the support ring 123 from the inner working tube 11 outward, significantly reducing the thermal bridge effect and qualitatively improving the overall insulation performance of the vacuum insulation layer. The polyimide composite material not only boasts excellent insulation performance but also possesses high strength, high modulus, and excellent creep resistance. This means it can provide durable and stable mechanical support under harsh downhole conditions of high temperature and high pressure, preventing vacuum cavity failure due to creep or yielding of the support components.

[0035] The L-shaped vertical cross-section structure of the scale plate 132 improves the coverage density and protection effect, preventing external objects from puncturing it; the rubber outer sleeve 141 and spring rib 142 of the outer insulation layer 14 further isolate external cold sources, enhancing the overall insulation performance and structural toughness; the connecting pipe 21 is used to connect the oil pipe fitting 1 to the external pipeline, ensuring smooth fluid transmission; the reinforcing ring 22 is set on the left end side surface of the connecting pipe 21 to enhance the mechanical strength of the connection; the inner wall of the outer pipe end 23 is provided with an internal thread groove and an inclined surface, which facilitates quick connection with other pipelines; the inner rubber ring 24 is located on the connection side of the internal thread groove and the inclined surface, providing an elastic seal to prevent leakage; the connecting pipe 21, the reinforcing ring 22 and the oil pipe fitting 1 adopt a double-stage sealing structure with laser sealing as the main method and special adhesive sealing as a supplement, ensuring the airtightness and reliability of the end connection, which is suitable for high-pressure environments.

[0036] The non-evaporable getter introduced in this invention can actively and continuously adsorb these gas molecules, which is equivalent to equipping the vacuum layer with a maintenance system. It effectively compensates for the impact of micro-leakage and gas release, thereby automatically maintaining the high vacuum degree in the interlayer and ensuring the long-term stability of the insulation effect. It fundamentally prevents performance failures caused by the slow deterioration of the vacuum degree, and transforms the effective service life of the oil pipe from a passive state that theoretically depends on zero leakage to an active state guaranteed by the life of the getter. The presence of the non-evaporable getter can adsorb residual gases that were not completely pumped out during the manufacturing process and gases released by the material during the initial operation, which is equivalent to providing fault tolerance for the manufacturing process. The non-evaporable getter is a solid film or bulk material that can maintain its activity at room temperature for a long time after being specially activated at high temperature. It is usually an alloy formed by adding elements such as vanadium and iron to zirconium as the matrix. Through a specific process, a porous and active film is formed on its surface.

[0037] The outer side of the inner working tube 11 is covered with multiple layers of ultra-thin metal foil, such as aluminum foil, stainless steel foil and high-temperature resistant mesh pad, which can effectively reflect radiant heat and reflect the heat radiated outward from the inner working tube 11 back layer by layer.

[0038] Working principle: When high-temperature fluids such as high-pour-point oil or heavy oil flow in the inner working pipe 11, the ultra-thin metal foil layer on the surface of the inner working pipe 11 reflects the heat radiated outward by the fluid back, reducing radiative heat loss. The vacuum insulation cavity of the vacuum sleeve 121 in the vacuum layer group 12 effectively blocks heat conduction and convection. The support ring 123, while maintaining the vacuum cavity structure, minimizes the thermal bridging effect due to its low thermal conductivity. The oil-specific outer pipe 131 and the scale plate 132 of the protective layer 13 provide mechanical protection and corrosion protection, ensuring that the internal structure can withstand downhole high pressure and... Undamaged in vibration environments, the rubber outer sleeve 141 and spring rib 142 of the outer insulation layer 14 further isolate external cold sources, enhancing overall insulation performance and structural toughness. The end joint fittings 2 ensure the sealing of the connection through a dual-stage sealing structure of laser sealing and special adhesive sealing, preventing fluid leakage and vacuum failure. At the same time, the non-evaporative getter inside the vacuum sleeve 121 continuously adsorbs gas molecules, automatically maintaining the stability of the vacuum layer inside the vacuum sleeve 121. The overall structure works in concert to effectively maintain the fluid temperature and prevent wax precipitation or solidification.

[0039] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A composite heat-insulating oil pipe, characterized in that, Includes an oil pipe fitting (1) and end fittings (2) connected to both ends of the oil pipe fitting (1), wherein the oil pipe fitting (1) further includes, The inner working tube (11) is covered with an ultra-thin metal foil layer for reflecting heat. A vacuum layer group (12) is provided on the outside of the ultra-thin metal foil layer of the inner working tube (11). The vacuum layer group (12) includes a vacuum tube sleeve (121) containing a vacuum insulation cavity inside. An external adhesive layer (122) is provided on the outside of the vacuum tube sleeve (121). Support rings (123) are installed in the annular groove at the left and right joints of the vacuum tube sleeve (121) with the end connector fittings (2). The protective layer (13) includes an oil-specific outer tube (131) disposed on the surface of the outer adhesive layer (122), the outer surface of which is surrounded and covered with a scale plate (132). The outer insulation layer (14) includes a rubber outer sleeve (141) covering the surface of the scale plate (132), and the surface of the rubber outer sleeve (141) is provided with spring ribs (142).

2. The composite heat-insulating oil pipe according to claim 1, characterized in that, The surface of the outer adhesive layer (122) is provided with a braided steel wire layer (124), and the braided steel wire layer (124) is arranged in a spiral braid.

3. The composite heat-insulating oil pipe according to claim 1, characterized in that, The support ring (123) is ring-shaped and supports the vacuum insulation cavity space of the vacuum tube sleeve (121). The support ring (123) is made of polyimide composite material with high strength and low thermal conductivity.

4. The composite heat-insulating oil pipe according to claim 1, characterized in that, The scale plate (132) is composed of multiple sheet plates stacked sequentially, and the vertical cross-section of the sheet plates of the scale plate (132) has an L-shaped structure.

5. A composite thermal insulation oil pipe according to claim 1, characterized in that, The surface of the rubber outer tube (141) is provided with a spiral groove that is adapted to the spring rib (142). The spring rib (142) is embedded and filled into the spiral groove of the rubber outer tube (141) and covered with the same material on the outside and heat-sealed.

6. The composite thermal insulation oil pipe according to claim 1, characterized in that, The end connector fitting (2) includes a connecting pipe (21) that is connected to the end side of the oil pipe fitting (1), and an external pipe end (23) is connected to the right side of the connecting pipe (21).

7. A composite thermal insulation oil pipe according to claim 6, characterized in that, The inner wall of the outer pipe end (23) is provided with an internal thread groove on the right side. The left side of the internal thread groove of the outer pipe end (23) is inclined. An inner rubber ring (24) is provided on the side where the internal thread groove of the outer pipe end (23) connects with the inclined surface.

8. A composite thermal insulation oil pipe according to claim 6, characterized in that, A reinforcing ring (22) is provided on the left side surface of the connecting pipe (21). The connection between the connecting pipe (21), the reinforcing ring (22) and the oil pipe fitting (1) adopts a double-level sealing structure with laser sealing as the main method and special adhesive sealing as the auxiliary method.

9. A composite thermal insulation oil pipe according to claim 1, characterized in that, The inner wall of the vacuum sleeve (121) is provided with a non-evaporable getter, which can continuously adsorb gas molecules generated by material release or micro-leakage to maintain a high vacuum in the interlayer.

Images