Anti-thaw collapse structure for buried crude oil pipeline in permafrost region

Abstract

The utility model discloses a thaw collapse prevention structure for a buried crude oil pipeline in a permafrost region. The buried pipeline disease prevention and control device mainly comprises a heat preservation structure, a support structure, a drainage system and a pipe top cover cap. The heat preservation structure comprises an anti-corrosion layer, a heat preservation layer and a protection layer. The thermal insulation layer can effectively reduce the thermal influence of the pipeline on permafrost, and the protective layer can prevent water and freeze to protect the internal thermal insulation layer. The supporting structure is used for supporting the pipeline and reducing heat influence of the bottom of the pipeline on frozen soil. The drainage system is used for draining water formed by melting frozen soil around the pipeline, the influence of water on soil is reduced, and the risk of thaw collapse is reduced. The pipe top cover cap plays a role in reducing heat exchange between the pipeline and the outside. The thaw collapse prevention structure can effectively reduce the risk that the buried pipeline in the permafrost region is affected by thaw collapse, guarantees safe operation of the pipeline, and has good anti-freezing performance and stability.

Description

Technical Field

[0001] The utility model relates to the field of pipe thawing and sinking prevention in permafrost areas, in particular to a thawing and sinking prevention structure for buried pipes in permafrost areas. Background Art

[0002] Climate warming has accelerated the melting of permafrost in permafrost areas, and buried pipeline projects in permafrost areas are prone to thaw-sinking disasters. As the temperature rises, the ice in the permafrost will melt, causing the moisture content in the soil to increase, causing the ground to lose its support and prone to subsidence. There are a large number of oil and gas resources in permafrost areas, and pipeline transportation is the most commonly used method. When buried pipelines in permafrost areas transport crude oil, since the temperature of crude oil is usually higher than the temperature of the surrounding permafrost, heat will be conducted from the pipeline to the permafrost layer around the pipeline, causing the permafrost to melt, resulting in the permafrost losing its original support and causing the soil to subside. On the other hand, melted ice will be converted into water, which will bring heat to the underlying soil, causing the pipeline to thaw and sink.

[0003] Therefore, in order to reduce the thermal impact of crude oil pipelines on the soil near the pipelines in permafrost areas, lower the temperature of the soil, prevent permafrost degradation, and prevent the thawing of the trench, reduce the impact of moisture on the soil, and improve the long-term stability of buried crude oil pipelines, a thawing and sinking prevention structure for buried crude oil pipelines in permafrost areas was designed. Utility Model Content

[0004] The purpose of the utility model is to provide a thawing-sinking prevention structure for buried crude oil pipelines in permafrost areas. It is used in buried pipeline projects in permafrost areas to reduce the thermal impact of buried crude oil pipelines on permafrost, prevent permafrost degradation, reduce the impact of frozen soil melting on pipeline systems, reduce soil thawing pressure, enhance pipeline stability, and reduce the risk of pipeline thawing.

[0005] The purpose of the utility model is to prevent the buried crude oil pipeline from melting and sinking in permafrost areas. Compared with the traditional buried pipeline laying structure, the pipeline structure of the utility model not only has better stability, but also can effectively reduce the impact of frozen soil melting on the pipeline.

[0006] The utility model is implemented by the following technical solutions:

[0007] An anti-thaw sinking structure for buried crude oil pipelines in permafrost areas includes a pipe top cap, surface soil backfill, shallow soil backfill, crude oil pipeline, insulation system, support structure, and drainage system. The bottom of the pipeline system is a support structure, and drainage systems are set on both sides of the support structure. The insulation system and crude oil pipeline are above it, and then shallow soil backfill, surface soil backfill, and pipe top cap are used in sequence.

[0008] The support structure is divided into a support support and an insulation support. The support support is made of 250mm thick reinforced concrete to ensure sufficient strength and stability to withstand the weight of the pipeline when fully loaded. The insulation support is made of 50mm thick polyurethane and has a 5% slope from the middle to both sides. The insulation support can reduce the heat exchange between the bottom of the pipeline and the frozen soil, effectively slowing down the transfer of heat from the pipeline to the frozen soil. At the same time, setting a 5% slope can better allow the water melted from the frozen soil near the pipeline to flow to the drainage system.

[0009] The outermost layer of the drainage system is a crushed stone filter layer, which can effectively filter larger particles and protect the inner materials. The inner sand filter layer plays a role in further filtering and purification, providing conditions for the smooth penetration of water. The middle part is a plastic blind ditch, which uses a mesh structure made of cold-resistant and corrosion-resistant fibers. Its outer diameter is 250mm, the inner diameter is 200mm, the surface opening rate reaches 95%, and the surface water absorption rate is extremely high. It can quickly absorb water and help accelerate the drainage process. A water collection pipe is set at the bottom of the blind ditch to facilitate the rapid discharge of collected water and ensure that the drainage system is unobstructed. At the same time, the cement board at the bottom can provide sufficient strength and flexibility to cope with melting and ground deformation, ensuring the long-term stable operation of the drainage system.

[0010] The insulation system consists of an anti-corrosion layer, a thermal insulation layer, and a protective layer. The bottom layer of the anti-corrosion layer is epoxy powder coating, the middle layer is adhesive, and the outer layer is polyethylene. This structure can effectively prevent pipeline corrosion. A 100mm thick hard polyurethane foam plastic is used as the thermal insulation layer outside the anti-corrosion layer. This thermal insulation layer can provide good thermal insulation performance, reduce energy loss, and reduce the thermal impact of oil flow heat on the frozen soil around the pipeline. Outside the thermal insulation layer, a 12mm thick high-density polyethylene plastic is used as a protective layer. This protective layer can provide additional protection to prevent external frozen soil and moisture from damaging the pipeline insulation layer.

[0011] The backfill area can improve the stability and safety of the pipeline support by backfilling in different soil layers. The top layer of frozen soil in permafrost areas is greatly affected by climate and human activities, and the degree of soil melting is high. The melting of frozen soil will cause greater deformation, posing a safety risk to the pipeline. The shallow soil backfill below 1000mm from the surface covers the entire structure. Selecting deeper shallow soil for backfilling can improve the stability and reliability of the pipeline. The topsoil between 0-1000mm is selected for backfilling. The topsoil is greatly affected by seasonal freeze-thaw and temperature changes. Using the topsoil backfill can reduce the amount of work and save costs, so it should be backfilled above the pipeline. After the backfill is completed, according to the local geological and weather conditions, a 400mm high pipe cap is built to reduce the heat exchange between the pipeline and the surface environment and prevent water accumulation inside the pipeline, reducing the impact of temperature fluctuations of buried pipelines on permafrost. Then restore vegetation, which helps to reduce the impact on the ecological environment and promote the recovery and stability of the ecosystem.

[0012] Compared with traditional structures, this anti-thaw sinking structure for buried pipelines in permafrost areas has the following advantages: 1. The protective layer of the insulation system can protect the pipeline from damage from the external environment, such as mechanical collision, corrosion, etc. It uses wear-resistant and corrosion-resistant materials, which can effectively extend the service life of the pipeline. 2. The insulation support effectively reduces the impact of heat at the bottom of the pipeline on the frozen soil and provides good insulation effect. 3. The support can enhance the stability and bearing capacity of the pipeline to ensure that the pipeline will not be displaced or damaged due to deformation of the surrounding soil. 4. In the pipeline buried in the permafrost area, the setting of the drainage system can timely remove the water generated by the melting of the soil in the hot season, keep the drainage around the pipeline unobstructed, and reduce the risk of pipeline thaw sinking. 5. Backfilling the surface soil and shallow soil layer can reduce the impact of freeze-thaw on the pipeline, reduce the thaw deformation and safety risks of the pipeline.

[0013] In summary, compared with traditional structures, this anti-thawing and sinking structure takes into account the special environment and working conditions of buried pipelines in permafrost areas more comprehensively, and has the advantages of better protecting pipelines, reducing the impact of permafrost meltwater on pipelines, and reducing the risk of pipeline thawing and sinking.

[0014] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description or be understood by implementing embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the anti-thawing structure of the buried pipeline in the permafrost region in this embodiment;

[0016] Figure 2 This is a schematic diagram of the cross-sectional structure of the pipeline insulation system in this embodiment;

[0017] Figure 3 This is an enlarged view of the bottom support structure details in this embodiment;

[0018] Figure 4 Schematic diagram of the drainage system in permafrost area in this embodiment.

[0019] Reference numerals of the above drawings:

[0020] 1- pipe top cap; 2- surface soil backfill; 3- shallow soil backfill; 4- crude oil pipeline; 5- insulation system; 6- support structure; 7- drainage system; 51- steel pipe wall; 52- anti-corrosion layer; 53- insulation layer; 54- protection layer; 61- insulation support; 62- support support; 71- crushed stone filter layer; 72- sand filter layer; 73- plastic blind ditch; 74- water collecting pipe; 75- cement board. DETAILED DESCRIPTION

[0021] In order to more clearly describe the purpose, technical solution and advantages of the utility model, the embodiments will be described in detail below. Please note that the embodiments are only some embodiments of the utility model, not all embodiments. Based on this embodiment, technicians in this field can obtain other embodiments without making creative efforts, and these embodiments also belong to the protection scope of the utility model. The technical solution of the utility model is shown in the accompanying drawings. According to the accompanying drawings, the present embodiment relates to an improved device or method, which is intended to solve the problems existing in the prior art. By using specific components and structures, the utility model can provide more efficient and reliable functions.

[0022] In the embodiments, the technical solution adopts a series of innovative designs and improvement measures to achieve some advantages.

[0023] As attached Figure 2 As shown, the anti-corrosion structure is first coated on the outer layer of the pipeline, epoxy resin is selected as the base layer, and a positioning bracket or fixing fixture is installed on the steel pipe to ensure the position and stability of the insulation layer.

[0024] The insulation system includes a steel pipe wall, an anti-corrosion layer and an insulation layer. The steel pipe wall is used as a supporting material. The anti-corrosion layer includes an epoxy powder coating base, an adhesive middle layer and an outer polyethylene layer. The epoxy powder coating base is used to prevent corrosion and oxidation. The insulation layer uses 100mm thick rigid polyurethane foam plastic, which is processed and shaped. Then the insulation material is put on the treated steel pipe and fixed with specific glue or tape to ensure a close connection between the insulation layer and the steel pipe. Finally, an outer protective layer is added to the outside of the insulation layer, and 12mm thick high-density polyethylene plastic is used as the outer sheath material to protect the insulation layer from external soil and moisture erosion and improve the overall mechanical strength and durability.

[0025] Lay the pipeline support structure at the bottom of the pipeline, such as the attached Figure 3 As shown, the pipeline support structure is divided into an insulation support and a support support. The insulation support is located on the upper side of the support structure, and the support support is located on the lower side of the support structure. The insulation support can reduce the impact of heat from the lower part of the pipeline on the frozen soil, and the support support can increase the stability of the pipeline.

[0026] The insulation support uses 50mm thick polyurethane foam as the insulation board to reduce the thermal impact of the bottom of the pipeline on the frozen soil. The insulation board is set with a slope of 5% from the middle to both sides. A 250mm thick reinforced concrete structure is used. The foundation pit is excavated and the foundation materials are filled and compacted to provide a stable foundation support for the pipeline support base to ensure that the pipeline will not be displaced or damaged due to deformation of the surrounding soil. After the base is installed, it needs to be adjusted and fixed to ensure that the base is completely attached to the pipeline and has sufficient bearing capacity. The installed pipeline support base is treated with anti-corrosion to improve its corrosion resistance and service life.

[0027] The drainage system is set on both sides of the pipeline support structure, including a crushed stone filter layer, a sand filter layer and a cement board. The crushed stone filter layer is located at the outermost layer of the drainage system to disperse the drainage pressure, while the sand filter layer is located at the inner layer to filter moisture and prevent soil loosening. The cement board is located at the bottom of the structure to stabilize the drainage system and prevent its deformation.

[0028] The outer layer uses a 100mm thick gravel filter layer, which has a high bearing capacity and can support the structure of the blind ditch. It has good pressure resistance and durability and can maintain stability for a long time. The inner layer uses a square sand filter layer with a side length of 350mm, which can effectively filter suspended matter, sediment, organic matter and other pollutants.

[0029] The inner layer of the drainage system also includes plastic blind ditches and water collection pipes. The plastic blind ditch is made of cold-resistant and corrosion-resistant fibers to form a three-dimensional mesh structure. It has the characteristics of high open porosity, pressure resistance, and strong cold resistance. The water collection pipe is located at the bottom of the plastic blind ditch and is used to collect moisture around the pipe.

[0030] The middle of the structure is a circular plastic blind ditch with an outer diameter of 250mm. The filter material is made of corrosion-resistant fiber and the mesh structure is made of modified polyethylene. Both have the advantage of never degrading in soil and water, and can maintain the characteristic of permanent material without change. There is a water collection pipe at the bottom of the plastic blind ditch to facilitate rapid discharge of water. A 100mm thick cement board is repaired at the bottom of the plastic blind ditch to support the entire drainage system and prevent deformation.

[0031] After the support structure, drainage system and pipeline laying are completed, backfill with shallow soil, and the backfill edge is 1000mm from the ground surface. Then choose to use the excavated topsoil to backfill until it is flush with the road surface, and then cap it, which can reduce the heat exchange between the pipeline and the outside world to a certain extent, facilitate the monitoring of soil settlement and maintenance around the underground pipeline, and then restore vegetation.

[0032] Finally, a few points should be explained: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "support", "backfill" and "anti-filter" should be understood in a broad sense, and "up", "down", "left" and "right" are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may change.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A thaw-proof structure for buried crude oil pipelines in permafrost areas, characterized by: It comprises a pipe top cap (1), surface soil backfill (2), shallow soil backfill (3), a crude oil pipeline (4), a thermal insulation system (5), a support structure (6), and a drainage system (7).

2. The anti-thaw sinking structure for buried crude oil pipeline in permafrost region according to claim 1, characterized in that: The support structure (6) is located at the bottom of the anti-melting structure, and the support structure (6) comprises a thermal insulation support (61) and a support support (62), wherein the thermal insulation support (61) is located on the upper side of the support structure (6), and the support support (62) is located on the lower side of the support structure (6).

3. The anti-thaw sinking structure for buried crude oil pipeline in permafrost region according to claim 1, characterized in that: The drainage system (7) comprises a crushed stone filter layer (71), a sandy filter layer (72) and a cement board (75), wherein the crushed stone filter layer (71) is located at the outermost layer of the drainage system (7), the sandy filter layer (72) is located at the inner layer, and the cement board (75) is located at the bottom of the structure.

4. The anti-thawing and sinking structure for buried crude oil pipelines in permafrost areas according to claim 1, characterized in that: The inner layer of the drainage system (7) further comprises a plastic blind ditch (73) and a water collecting pipe (74), wherein the plastic blind ditch (73) is a three-dimensional mesh structure made of fibers, and the water collecting pipe (74) is located at the bottom of the plastic blind ditch (73).

5. The anti-thawing and sinking structure for buried crude oil pipelines in permafrost areas according to claim 1, characterized in that: The thermal insulation system (5) comprises an anti-corrosion layer (52) and a thermal insulation layer (53), wherein the anti-corrosion layer (52) comprises a bottom epoxy powder coating layer, a middle adhesive layer and an outer polyethylene layer, and the thermal insulation layer (53) is a 100 mm thick rigid polyurethane foam plastic.

6. The anti-thaw sinking structure for buried crude oil pipeline in permafrost region according to claim 1, characterized in that: The thermal insulation system (5) further comprises a protective layer (54), wherein the protective layer (54) is a 12 mm thick high-density polyethylene plastic.

7. The anti-thawing and sinking structure for buried crude oil pipelines in permafrost areas according to claim 1, characterized in that: The shallow soil backfill (3) covers the entire structure below 1000 mm from the ground surface.

8. The anti-thawing and sinking structure for buried crude oil pipelines in permafrost areas according to claim 1, characterized in that: The thickness of the topsoil backfill (2) is 0-1000 mm.

9. The anti-thawing and sinking structure for buried crude oil pipelines in permafrost regions according to claim 1, characterized in that: The height of the pipe top cap (1) is 400m.

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