Pipe embankment structure of oil and gas pipeline in permafrost region and intelligent regulation and control method

Abstract

The invention relates to a pipe embankment structure of an oil and gas pipeline in a permafrost region and an intelligent regulation and control method. The pipe embankment structure comprises a soil filling layer, a pipeline protection layer, a crude oil pipeline, a gas conveying pipeline, an intelligent regulation and control system, a fine sand layer, a heat preservation layer, a heat flow sensor, a drainage ditch and a reference heat flow sensor. A crude oil pipeline (positive temperature operation) and a gas pipeline (negative temperature operation) are reasonably arranged, energy flow is monitored in real time in combination with a heat flow sensor, and an abnormal alarm is triggered when energy changes abnormally. Meanwhile, the intelligent regulation and control system is used for collecting temperature data of the pipeline and the frozen soil layer in real time, the operation temperature of the gas pipeline is dynamically adjusted, and heat effect control is optimized. According to the technical scheme, degradation of the permafrost underlying the crude oil pipeline can be effectively treated through reasonable layout and dynamic regulation and control, meanwhile, frost heaving deformation of soil around the gas conveying pipeline is slowed down, and therefore the thaw collapse and frost heaving problems caused by oil and gas pipelines in the permafrost region are remarkably solved.

Description

Technical Field

[0001] The present application relates to the technical field of pipe embankment structures, and specifically, to a pipe embankment structure and an intelligent control method for oil and gas pipelines in permafrost areas. Background Art

[0002] Permafrost accounts for 25% of the world's land area. As the world's third largest frozen country, my country's permafrost area accounts for about 22.4% of its land area. Permafrost areas contain a large amount of oil and gas resources, and pipeline transportation is the most convenient and economical mode of transportation. In the traditional design of buried pipelines in permafrost areas, crude oil pipelines usually operate at positive temperatures, while natural gas pipelines are mostly operated at negative temperature conditions. Crude oil pipelines will release heat to the surrounding permafrost, causing permafrost melting and foundation settlement; gas pipelines will absorb heat from the surrounding permafrost, causing excessive frost heave and deformation of the permafrost. The impact of this imbalance of cold and heat will reduce the long-term stability and safety of oil and gas pipelines in permafrost areas.

[0003] At present, in order to avoid the problem of thawing, subsidence and frost heaving in oil and gas pipelines, crude oil pipelines have adopted methods such as adding insulation materials to the outer pipe wall and reducing the temperature of crude oil transportation to delay the degradation of permafrost. However, these traditional measures still have many limitations and cannot fundamentally solve the problem of thawing, subsidence and frost heaving faced by oil and gas pipelines in permafrost areas. Therefore, an innovative technical solution is urgently needed to dynamically adjust the temperature of oil and gas pipelines through reasonable layout and intelligent regulation, reduce the thermal impact of pipelines on frozen soil, thereby effectively preventing frozen soil from melting and frost heaving, and significantly improving the stability and safety of oil and gas pipelines in permafrost areas. Summary of the invention

[0004] In order to solve the problem of thermal thaw subsidence encountered by traditional oil and gas pipelines when operating in permafrost areas, the present invention proposes a pipe embankment structure for oil and gas pipelines in permafrost areas, which aims to dynamically regulate pipeline operation and real-time regulate pipeline temperature and surrounding frozen soil environment, thereby improving the long-term stability and safety of the pipeline.

[0005] In order to achieve the above objectives, the present invention proposes an oil and gas pipeline embankment structure, which achieves heat neutralization by rationally arranging crude oil pipelines and gas pipelines, and is equipped with an intelligent monitoring and control system to reduce the thermal effect of the embankment structure on permafrost. The structure also includes a fine sand layer, an insulation layer, a drainage ditch, etc., and comprehensively considers aspects such as heat transfer, permafrost protection and structural stability to ensure the long-term stability of the pipeline. By using the principle of energy conservation, the heat released by the crude oil pipeline is absorbed by the negative temperature gas pipeline.

[0006] As a preferred technical solution of the present invention, the reasonable layout of the crude oil pipeline and the gas pipeline achieves heat neutralization and reduces the thermal effect on the permafrost. The distance between the crude oil pipeline and the gas pipeline is 2m, the bottom is located at the same horizontal plane, and they are buried on both sides of the pipe embankment to achieve mutual neutralization of the cold and hot effects and reduce the thermal impact on the underlying permafrost.

[0007] As a preferred technical solution of the present invention, the outer surfaces of the crude oil pipeline and the gas pipeline are wrapped with a pipeline protective layer, which is made of a composite material with waterproof, corrosion-resistant and anti-oxidation properties. The bottom layer is epoxy powder coating, the middle layer is adhesive, and the outer layer is polyethylene. This structure can effectively prevent pipeline corrosion, thereby enhancing the protective performance of the pipeline and reducing the impact of the external environment on the pipeline and pipe embankment structure.

[0008] As a preferred technical solution of the present invention, the fine sand layer has good thermal conductivity, which allows the waste heat of the crude oil pipeline to be laterally conducted to the cold source of the gas pipeline, thereby achieving local energy offset. Through its strong buffering effect, it reduces the deformation of the pipeline caused by the expansion or contraction of frozen soil, thereby further stabilizing the frozen soil layer.

[0009] As a preferred technical solution of the present invention, the insulation layer is made of polyurethane foam or other insulation materials with low thermal conductivity, with a thickness of 10 cm, and is laid 10 cm below the oil and gas pipeline. This layout effectively prevents heat from being transferred to the underlying soil, thereby ensuring better heat neutralization between the upper crude oil pipeline and the gas pipeline, and mitigating the impact on the underlying permafrost.

[0010] As a preferred technical solution of the present invention, the drainage ditch has an anti-seepage design and has an anti-seepage function, and a gravel layer is arranged at its bottom. This design is intended to ensure that any melt water or seepage water can be quickly conducted away to avoid water accumulation inside the pipe embankment structure.

[0011] The present invention also includes an intelligent monitoring and control system that can monitor the temperature of the pipeline and the temperature of the frozen soil layer in real time, adjust the operating temperature of the pipeline according to seasonal changes, and further reduce the impact of thermal effects on the frozen soil. It includes the following steps: Step S1: When the heat flow sensor detects the current heat flow value q Greater than the preset threshold q t When the abnormal alarm is triggered; Step S2: Start the intelligent detection system to monitor the temperature of the crude oil pipeline, the gas pipeline and the frozen soil; Step S3: determine whether the temperature of the crude oil pipeline and the gas pipeline is within the preset safety range; if it is detected that the temperature exceeds the safety range, an abnormal alarm is triggered and a cooling program is started; Step S4: Perform heat calculations and adjust the temperature of the gas pipeline to maintain thermal balance and ensure frozen soil stability.

[0012] As the preferred technical solution of the present invention, the heat flux sensor formula is: heat flux density q Used to monitor the energy exchange between the upper and lower parts of the pipeline. When too much energy is transferred from the upper part to the lower part ( q >0), which proves that the energy neutralization effect of the upper part is not good, then reduce the temperature of the gas pipeline, the formula is as follows: q : Heat flux density (W / m²), which indicates the amount of heat passing through a unit area per unit time; ΔT is the temperature difference on both sides of the heat flow sensor (°C); Δx is the thickness of the heat flux sensor on both sides (m).

[0013] As a preferred technical solution of the present invention, the reference heat flow sensor: monitors the reference heat flow in the area q t The reference heat flux sensor is buried 10 meters from the foot of the roadbed. q t is the preset threshold.

[0014] As a preferred technical solution of the present invention, heat flow abnormality detection and alarm: compare the current heat flow value q With preset threshold q t ,like q > q t or q < q t, Trigger abnormal alarm (excess energy or insufficient energy in the system). The formula is: The energy released and absorbed by the oil and gas pipeline is calculated based on the monitored temperature. The formula is as follows: Heat released by crude oil pipeline Qo: Qo: heat per unit length released by the crude oil pipeline (W / m); Tp: crude oil pipeline temperature (℃); Te: frozen soil environment temperature (℃); ks: heat transfer coefficient of frozen soil layer (W / m²·℃); r1: frozen soil environment temperature; r2: thermal influence radius of crude oil pipeline (m); The heat absorbed by the gas pipeline is Qg: Qg: heat per unit length absorbed by the gas pipeline (W / m); Tg: temperature of the gas pipeline (℃); r3: radius of the outer wall of the gas pipeline (m); r4: heat-affected radius of the gas pipeline (m); As a preferred technical solution of the present invention, the heat neutralization formula is: According to the law of conservation of energy, the heat Qo released by the crude oil pipeline is equal to the heat Qg absorbed by the gas pipeline: Expanding the formula yields: After simplification, the gas pipeline temperature T can be obtained g : When performing the calculation, the impact of temperature changes on oil and gas pipelines is not considered. In addition, in the warm season: when the crude oil pipeline temperature T p When it is high, reduce the gas pipeline T g , so that the thermal effects of the two are neutralized and the scope of frozen soil melting is reduced. In cold season: when the crude oil pipeline temperature T p When the temperature is low, increase the gas pipeline temperature T g , compensate for heat and prevent frozen soil from heaving.

[0015] In summary, the oil and gas pipeline embankment structure and intelligent control method of the present invention provide an effective solution for the safe operation of oil and gas pipelines in permafrost areas by comprehensively considering multiple aspects such as heat neutralization, intelligent monitoring and structural stability.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) By rationally arranging crude oil pipelines and gas pipelines, the difference in operating temperatures between the two can be used to achieve heat neutralization, effectively reducing the thermal impact on permafrost; (2) Dynamically adjust the temperature of the gas pipeline through monitoring data, optimize thermal effect control, and reduce energy consumption; (3) Through the design of the pipe embankment structure, the heat of the crude oil pipeline and the gas pipeline can be neutralized above the permafrost to reduce the thermal impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 In this embodiment, a pipe embankment structure of an oil and gas pipeline in a permafrost region; Figure 2 Schematic diagram of the intelligent control method in this embodiment; Indicated in the figure are: fill layer (1), pipeline protection layer (2), crude oil pipeline (3), gas pipeline (4), intelligent control system (5), fine sand layer (6), insulation layer (7), heat flow sensor (8), drainage ditch (9), permafrost layer (10), and reference heat flow sensor (11). DETAILED DESCRIPTION

[0019] In order to more clearly describe the purpose, technical solutions and advantages of the present application, the embodiments will be described in detail below. Please note that the embodiments are only some embodiments of the present application, rather than all embodiments. Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents the selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present application.

[0020] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0021] The technical solution in this application will be described below in conjunction with the accompanying drawings.

[0022] Example 1: Figure 1 As shown, this embodiment provides a pipe embankment structure for oil and gas pipelines in permafrost areas, which can solve the problem of permafrost degradation caused by operating crude oil pipelines at normal temperatures in permafrost areas, solve the problem of thermal thaw settlement of crude oil pipelines, and improve the long-term stability of oil and gas pipelines in permafrost areas. The main method of heat and cold neutralization of oil and gas pipelines is adopted, and the pipe embankment is built above the natural frozen ground, which can effectively slow down the problem of permafrost degradation at the bottom of the pipe embankment.

[0023] The buried structure of oil and gas pipelines in permafrost areas includes fill layer, crude oil pipeline, gas pipeline, pipeline protection layer, insulation layer, intelligent control system, fine sand layer, drainage ditch, and reference heat flow sensor; First, according to the design requirements, the bottom of the roadbed is leveled and drainage ditches are built. A reference heat flow sensor is buried 10m from the foot of the roadbed slope. Then fill the bottom of the roadbed with soil to 50cm, and use professional equipment to fill the soil to ensure that the materials are evenly distributed and filled in place. After filling, use professional equipment to compact the roadbed to ensure that the compaction reaches or exceeds 95% to provide a stable bearing foundation. Then bury a heat flow sensor in the middle of the top of the roadbed to detect the heat flow conditions of the upper and lower parts; Laying a 10cm insulation layer on the roadbed, made of polyurethane foam or other low thermal conductivity insulation materials, effectively prevents heat transfer to the fill layer, while ensuring better heat neutralization between the upper crude oil pipeline and the gas pipeline; Then, a fine sand layer is laid, and the fine sand layer is laid on the upper side of the bottom fill, wherein the maximum diameter of the fine sand is no more than 0.2 cm, and the thickness of the fine sand layer is 10 cm; After the fine sand layer is laid, the temperature monitoring points of the oil and gas pipelines of the intelligent control system and the construction of the oil and gas pipelines are carried out. During this process, the crude oil pipeline and the gas pipeline are precisely installed in the central area of ​​the pipe embankment structure, specifically 1.2m below the fill layer. This layout ensures the core position of the pipeline in the pipe embankment structure. The crude oil pipeline and the gas pipeline are arranged in parallel with an interval of 2m. This is conducive to the effective management and control of heat. The outer surfaces of the crude oil pipeline and the gas pipeline are wrapped with a pipeline protective layer to reduce the impact of the external environment on the pipeline and the pipe embankment structure; After the pipeline is laid, the pipe embankment is filled with soil. The ground is constructed in a trapezoidal shape, ensuring that the height of the pipe embankment is 2.4m, and the slope on both sides of the trapezoid is set to 1:1.5. This step requires precise construction and measurement to ensure the stability and safety of the overall structure.

[0024] Example 2: Figure 2 As shown, a method for intelligently controlling the pipe embankment structure of an oil and gas pipeline in a permafrost region includes the following steps: Step S1: When the heat flow sensor detects that the current heat flow value q is greater than the preset threshold value qt, an abnormal alarm is triggered; Step S2: Start the intelligent detection system to monitor the temperature of the crude oil pipeline, the gas pipeline and the frozen soil; Step S3: determine whether the temperature of the crude oil pipeline and the gas pipeline is within the preset safety range; if it is detected that the temperature exceeds the safety range, an abnormal alarm is triggered and a cooling program is started; Step S4: Perform heat calculations and adjust the temperature of the gas pipeline to maintain thermal balance and ensure frozen soil stability.

[0025] In order to verify the prevention and control effect of the intelligent control method for the pipe embankment structure of an oil and gas pipeline in a permafrost region provided in this embodiment, the present invention uses the China-Russia crude oil pipeline as an example to verify the formula: Example: At this time, when q>qt is detected, the heat sensor alarms and the intelligent control system is turned on. Monitor the crude oil pipe wall temperature T p is 5℃, gas pipe wall T g The temperature is -1℃, the crude oil pipeline and gas pipeline are within the safe range, and the heat transfer coefficient of the frozen soil layer is k s is 1.9W / m²·℃, soil temperature T eThe temperature is 1℃, the radius of the oil and gas pipeline is 0.81m, and the heat affected radius is 2m; At this time, the energy Qo released by the crude oil pipeline is: The crude oil pipeline Qo≈54.95W / m, and the energy to be released is 54.95W / m; At this time, the energy Qg absorbed by the gas pipeline is: Gas pipeline Qg≈-26.35W / m, energy required to be absorbed is 26.35W / m; In order to reduce the thermal impact of crude oil pipelines on frozen soil, adjust T g ; Adjusted gas pipeline T g It is -3℃, at which time energy neutralization can be achieved.

[0026] Through case calculation and analysis, it is found that the oil and gas pipeline embankment structure can achieve energy neutralization, alleviate the problem of permafrost melting and sinking caused by hot oil pipelines and frost heaving caused by gas pipelines, and improve the long-term stability of oil and gas pipelines in permafrost areas; 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 "installation", "backfilling", "laying" should be understood in a broad sense, and "upper", "lower", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may change; The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present application should be included in the protection scope of the present application.

Claims

1. A pipe embankment structure for an oil and gas pipeline in a permafrost region, characterized in that: include: Filling layer (1), pipeline protection layer (2), crude oil pipeline (3), gas pipeline (4), intelligent control system (5), fine sand layer (6), insulation layer (7), heat flow sensor (8), drainage ditch (9), permafrost layer (10), and reference heat flow sensor (11).

2. The oil and gas pipeline embankment structure according to claim 1, characterized in that: The crude oil pipeline (3) operates under positive temperature conditions, and the gas pipeline (4) operates under negative temperature conditions. The distance between the oil and gas pipelines is 2m, and the bottoms are located at the same horizontal plane.

3. The oil and gas pipeline embankment structure according to claim 1, characterized in that: The thermal insulation layer (7) is made of polyurethane foam material, has a thermal conductivity of ≤0.03 W / (m·°C), and a thickness of 10 cm.

4. The oil and gas pipeline embankment structure according to claim 1, characterized in that: Heat flow sensor (8) is used to monitor the current heat flow value q , the formula is as follows: ； q : Heat flux density (W / m²), which indicates the amount of heat passing through a unit area per unit time; Δ T is the temperature difference on both sides of the heat flow sensor (°C); Δ x is the thickness of the heat flux sensor on both sides (m).

5. The oil and gas pipeline embankment structure according to claim 1, characterized in that: The reference heat flow sensor (11) is buried 10 meters from the foot of the roadbed slope to monitor the reference heat flow value in the area. q t , and use it as the preset threshold.

6. The thermal flow sensor according to claim 4, characterized in that: Current heat flow value q Greater than the preset threshold q t When , the heat flux sensor alarms abnormally, the formula is:

7. An intelligent control method for the pipe embankment structure of an oil and gas pipeline in a permafrost region based on any one of claims 1 to 6, characterized in that: The following steps are involved: Step S1: When the heat flow sensor detects the current heat flow value q Greater than the preset threshold q t When the abnormal alarm is triggered; Step S2: Start the intelligent detection system to monitor the temperature of the crude oil pipeline, the gas pipeline and the frozen soil; Step S3: determine whether the temperature of the crude oil pipeline and the gas pipeline is within the preset safety range; if it is detected that the temperature exceeds the safety range, an abnormal alarm is triggered and a cooling program is started; Step S4: Perform heat calculations and adjust the temperature of the gas pipeline to maintain thermal balance and ensure frozen soil stability.

8. The intelligent control method according to claim 7, characterized in that: It also includes calculating the heat released by crude oil pipelines Q o : ； Q o : Heat per unit length released by crude oil pipeline (W / m); T p : Crude oil pipeline temperature (℃); T e : frozen soil environment temperature (℃); k s : heat transfer coefficient of frozen soil layer (W / m²·℃); r1: outer wall radius of crude oil pipeline (m); r2: heat affected radius of crude oil pipeline (m).

9. The intelligent control method according to claim 7, characterized in that: It also includes calculating the heat absorbed by the gas pipeline Q g : ； Q g : Heat per unit length absorbed by the gas pipeline (W / m); T g : gas pipeline temperature (℃); r3: gas pipeline outer wall radius (m); r4: gas pipeline heat affected radius (m).

10. The intelligent control method according to claim 7, characterized in that: Also includes the heat released by crude oil pipelines Q o and the heat absorbed by the gas pipeline Q g equal: ； Expanding the formula yields: ； After simplification, the gas pipeline temperature can be obtained T g : 。

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