A pipeline embankment structure and intelligent control method for an oil and gas pipeline in a permafrost region

Abstract

The present application relates to a kind of permafrost region oil and gas pipeline's pipe embankment structure and intelligent control method.The pipe embankment structure includes fill layer, pipeline protection layer, crude oil pipeline, gas pipeline, intelligent control system, fine sand layer, heat preservation layer, heat flow sensor, drainage ditch, benchmark heat flow sensor.By reasonable layout crude oil pipeline (positive temperature operation) and gas pipeline (negative temperature operation), in combination with heat flow sensor real-time monitoring energy flow, and trigger abnormal alarm when energy abnormal change.At the same time, using intelligent control system real-time acquisition pipeline and frozen soil layer temperature data, dynamically adjust the operating temperature of gas pipeline, optimize heat effect control.The technical scheme provided by the present application can be reasonably laid out and dynamically regulated, effectively govern the degradation of underlying permafrost under crude oil pipeline, while slowing down the frost heaving deformation of soil around gas pipeline, thereby significantly improving the thawing and frost heaving problems caused by oil and gas pipeline in permafrost region.

Description

Technical Field

[0001] This application relates to the field of embankment structure technology, specifically, a embankment structure for oil and gas pipelines in permafrost regions and an intelligent control method. Background Technology

[0002] Permafrost covers 25% of the global land area, and my country, as the world's third-largest permafrost country, has permafrost covering approximately 22.4% of its land area. Permafrost regions contain abundant oil and gas resources, and pipeline transportation is the most convenient and economical mode of transport. In traditional buried pipeline design for permafrost regions, crude oil pipelines typically operate at positive temperatures, while natural gas pipelines are mostly under negative temperature conditions. Crude oil pipelines release heat into the surrounding permafrost, causing permafrost thawing and ground subsidence; gas pipelines absorb heat from the surrounding permafrost, leading to excessive frost heave and deformation. This imbalance between heat and cold reduces the long-term stability and safety of oil and gas pipelines in permafrost regions.

[0003] Currently, to avoid thaw settlement and frost heave problems in oil and gas pipelines, crude oil pipelines employ methods such as adding insulation materials to the outer pipe walls and reducing the temperature of transported crude oil to slow down the degradation of permafrost. However, these traditional measures still have many limitations and cannot fundamentally solve the thaw settlement and frost heave problems faced by oil and gas pipelines in permafrost regions. Therefore, there is an urgent need for an innovative technical solution that, through rational layout and intelligent control, dynamically adjusts the temperature of oil and gas pipelines to reduce the thermal impact of pipelines on permafrost, thereby effectively preventing permafrost thawing and frost heave, and significantly improving the stability and safety of oil and gas pipelines in permafrost regions. Summary of the Invention

[0004] To address the thermal thawing and subsidence problem encountered by traditional oil and gas pipelines operating in permafrost regions, this invention proposes a pipe embankment structure for oil and gas pipelines in permafrost areas. The aim is to dynamically regulate pipeline operation and control pipeline temperature and the surrounding permafrost environment in real time, thereby improving the long-term stability and safety of the pipeline.

[0005] To achieve the above objectives, this invention proposes an oil and gas pipeline embankment structure. By rationally arranging the crude oil pipeline and gas pipeline, heat neutralization is achieved. Equipped with an intelligent monitoring and control system, the thermal effect of the embankment structure on permafrost can be reduced. This structure also includes a fine sand layer, an insulation layer, and drainage ditches, comprehensively considering heat transfer, permafrost protection, and structural stability to ensure the long-term stability of the pipeline. Utilizing the principle of energy conservation, the heat released by the crude oil pipeline is absorbed by the sub-zero gas pipeline.

[0006] As a preferred technical solution of the present invention, the rational layout of the crude oil pipeline and the gas pipeline achieves heat neutralization and reduces the thermal effect on the permafrost. The crude oil pipeline and the gas pipeline are spaced 2m apart, with their bottoms on the same horizontal plane, and are buried on both sides of the pipe embankment to achieve mutual neutralization of the cold and heat effects and reduce the thermal impact on the underlying permafrost.

[0007] As a preferred embodiment of the present invention, both crude oil pipelines and gas pipelines are covered with a protective layer made of a composite material with waterproof, corrosion-resistant, and oxidation-resistant properties. The bottom layer is an epoxy powder coating, the middle layer is an adhesive, and the outer layer is polyethylene. This structure effectively prevents pipeline corrosion, thereby enhancing the pipeline's protective performance and reducing the impact of the external environment on the pipeline and embankment structure.

[0008] As a preferred technical solution of the present invention, the fine sand layer has good thermal conductivity, which allows the residual heat of the crude oil pipeline to be conducted laterally to the cold source of the gas pipeline, thereby achieving local energy offsetting. Furthermore, through its strong buffering effect, it reduces the deformation of the pipeline caused by the expansion or contraction of frozen soil, and further stabilizes 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 10cm, and is laid 10cm below the oil and gas pipeline. This layout effectively prevents heat from being transferred to the lower soil layer, 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 an anti-seepage function, and a layer of crushed stone is set at its bottom. This design is intended to ensure that any meltwater or seepage can be quickly diverted away, and to prevent water from accumulating inside the pipe embankment structure.

[0011] This invention also includes an intelligent monitoring and control system capable of real-time monitoring of pipeline temperature and permafrost temperature, adjusting the pipeline operating temperature according to seasonal changes, and further reducing the impact of thermal effects on permafrost. The system includes the following steps:

[0012] Step S1: When the heat flux sensor detects the current heat flux value q Greater than the preset threshold q t When this occurs, an abnormal alarm is triggered;

[0013] Step S2: Activate the intelligent detection system to monitor the temperature of crude oil pipelines, gas pipelines, and frozen soil.

[0014] S3 step: Determine whether the temperature of the crude oil pipeline and gas pipeline is within the preset safe range; if the temperature is detected to be outside the safe range, trigger an abnormal alarm and start the cooling program;

[0015] Step S4: Perform heat calculations and adjust the temperature of the gas pipeline to maintain thermal balance and ensure the stability of the frozen soil.

[0016] The control formula is as follows:

[0017] As a preferred technical solution of the present invention, the heat flux sensor formula is: heat flux density. q Used to monitor energy exchange between the upper and lower parts of a pipeline; when too much energy is transferred from the upper part to the lower part ( q If the value is greater than 0, it indicates that the energy neutralization effect in the upper part is not good. Therefore, the temperature of the gas pipeline should be reduced, and the formula is as follows:

[0018]

[0019] q: Heat flux density (W / m²), representing the amount of heat passing through a unit area per unit time; ΔT is the temperature difference (°C) between the two sides of the heat flux sensor; Δx is the thickness (m) between the two sides of the heat flux sensor.

[0020] As a preferred technical solution of the present invention, a reference heat flow sensor is used to monitor the reference heat flow of the region. q t The reference heat flow sensor is buried 10 meters horizontally from the toe of the roadbed slope. q t This is a preset threshold.

[0021] As a preferred technical solution of the present invention, heat flux anomaly detection and alarm: comparing the current heat flux value q With preset threshold q t ,like q > q t or q < q t This triggers an abnormal alarm (excess or insufficient energy in the system). The formula is:

[0022]

[0023] As a preferred technical solution of the present invention, the energy released and absorbed by the oil and gas pipeline is calculated based on the monitored temperature, using the following formula:

[0024] Crude oil pipeline releases heat Q o :

[0025]

[0026] Q o Heat released per unit length of crude oil pipeline (W / m); Tp Crude oil pipeline temperature (°C); T e : Temperature of frozen soil environment (°C); k s : Heat transfer coefficient of frozen soil (W / m²·℃); r1: Frozen soil ambient temperature; r2: Heat-affected radius of crude oil pipeline (m).

[0027] Gas pipelines absorb heat Q g :

[0028]

[0029] Q g Heat absorbed per unit length of gas pipeline (W / m); T g : Gas pipeline temperature (°C); r3: Gas pipeline outer wall radius (m); r4: Gas pipeline heat-affected radius (m).

[0030] As a preferred technical solution of the present invention, the heat neutralization formula is as follows: According to the law of conservation of energy, the heat released by the crude oil pipeline... Q o Heat absorbed by gas pipelines Q g equal:

[0031]

[0032] Expanding the formula, we get:

[0033]

[0034] The temperature of the gas pipeline can be obtained after simplification. T g :

[0035]

[0036] The impact of temperature changes on oil and gas pipelines is not considered in the calculation examples. Furthermore, during the warm season: when the temperature of the crude oil pipeline... T p When the temperature is high, lower the gas pipeline. T g This neutralizes the thermal effects of both, reducing the extent of permafrost thawing. During the cold season: when the temperature of the crude oil pipeline... T p When the temperature is low, increase the gas pipeline temperature. T g It compensates for heat and prevents the frozen soil layer from frost heave.

[0037] 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.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] By rationally arranging crude oil pipelines and gas pipelines, the difference in their operating temperatures can be used to neutralize heat and effectively reduce the thermal impact on permafrost.

[0040] By dynamically adjusting the temperature of gas pipelines based on monitoring data, thermal effect control can be optimized, thereby reducing energy consumption.

[0041] By designing the pipe embankment structure, the heat from crude oil pipelines and gas pipelines is neutralized on the permafrost, reducing the thermal impact. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This embodiment describes a pipe embankment structure for an oil and gas pipeline in a permafrost region.

[0044] Figure 2 A schematic diagram of the intelligent control method in this embodiment;

[0045] The diagram shows: 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 Implementation

[0046] To more clearly describe the purpose, technical solution, and advantages of this application, the embodiments will be described in detail below. Please note that the embodiments described are only some embodiments of this application, not all embodiments. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0047] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0048] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0049] Example 1: As Figure 1 As shown, this embodiment provides a pipe embankment structure for oil and gas pipelines in permafrost regions. This structure addresses the problem of permafrost degradation caused by crude oil pipelines operating at positive temperatures in permafrost areas, resolves the issue of thermal thawing and subsidence of crude oil pipelines, and improves the long-term stability of oil and gas pipelines in permafrost regions. The main approach is to neutralize the thermal effects of the oil and gas pipeline by constructing a pipe embankment above the natural permafrost surface, which effectively mitigates the degradation of permafrost beneath the embankment.

[0050] The structure for laying oil and gas pipelines in permafrost regions includes a backfill layer, crude oil pipeline, gas pipeline, pipeline protection layer, insulation layer, intelligent control system, fine sand layer, drainage ditch, and reference heat flow sensor.

[0051] First, according to design requirements, the bottom of the roadbed is leveled and drainage ditches are constructed. A reference heat flow sensor is installed 10m from the toe of the roadbed slope. Then, soil is backfilled to a depth of 50cm at the bottom of the roadbed using specialized equipment to ensure even distribution and proper filling. After backfilling, the roadbed is compacted using specialized equipment to ensure a compaction degree of 95% or higher, providing a stable load-bearing foundation. Finally, a heat flow sensor is installed in the middle of the top of the roadbed to monitor heat flow in both the upper and lower sections.

[0052] A 10cm insulation layer, made of polyurethane foam or other low thermal conductivity insulation materials, is laid on the roadbed to effectively prevent heat from being transferred to the fill layer, while ensuring better heat neutralization between the upper crude oil pipeline and the gas pipeline.

[0053] Then a fine sand layer is laid on top of the bottom fill soil. 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.

[0054] After the fine sand layer was laid, the construction of the intelligent control system's oil and gas pipeline temperature monitoring points and the oil and gas pipelines themselves commenced. During this process, the crude oil pipeline and gas pipeline were precisely installed in the central area of ​​the embankment structure, specifically 1.2 meters below the fill layer. This layout ensured the pipelines' core position within the embankment structure. The crude oil pipeline and gas pipeline were arranged parallel to each other, spaced 2 meters apart. This facilitated effective heat management and control. Both the crude oil pipeline and gas pipeline were covered with a protective layer to reduce the impact of the external environment on the pipelines and the embankment structure.

[0055] After the pipeline is laid, the embankment is backfilled, forming a trapezoidal structure on the ground. The embankment height is ensured to be 2.4m, and the slope on both sides of the trapezoid is set at 1:1.5. This step requires precise construction and measurement to ensure the stability and safety of the overall structure.

[0056] Example 2: As Figure 2 As shown, an intelligent control method for the embankment structure of oil and gas pipelines in permafrost regions is proposed. The method includes the following steps:

[0057] Step S1: When the heat flux sensor detects the current heat flux value q Greater than the preset threshold q t When this occurs, an abnormal alarm is triggered;

[0058] Step S2: Activate the intelligent detection system to monitor the temperature of crude oil pipelines, gas pipelines, and frozen soil.

[0059] S3 step: Determine whether the temperature of the crude oil pipeline and gas pipeline is within the preset safe range; if the temperature is detected to be outside the safe range, trigger an abnormal alarm and start the cooling program;

[0060] Step S4: Perform heat calculations and adjust the temperature of the gas pipeline to maintain thermal balance and ensure the stability of the frozen soil.

[0061] To verify the effectiveness of the intelligent control method for the embankment structure of oil and gas pipelines in permafrost regions provided in this embodiment, the present invention uses the China-Russia crude oil pipeline as an example to perform formula verification:

[0062] Example: At this time, it was detected q > q t The heat sensor alarm activates, triggering the intelligent control system. This monitors the crude oil pipe wall temperature. T p The gas pipeline wall is at 5°C. T g At -1℃, the crude oil pipelines and gas pipelines did not exceed the safe range, and the heat transfer coefficient of the permafrost layer was... k s The soil temperature is 1.9 W / m²·℃. T e The temperature is 1℃, the radius of the oil and gas pipelines is 0.81m, and the heat-affected radius is 2m.

[0063] At this time, the energy released by the crude oil pipeline Q o for:

[0064]

[0065] crude oil pipeline Q o≈54.95W / m, requiring the release of 54.95W / m of energy;

[0066] At this time, the energy absorbed by the gas pipeline Q g for:

[0067]

[0068] Gas pipeline Q g ≈-26.35W / m, requiring energy absorption of 26.35W / m;

[0069] To reduce the thermal impact of crude oil pipelines on permafrost, adjustments were made. T g ;

[0070]

[0071] Adjusted gas pipeline T g The temperature is -3℃, at which point energy neutralization can be achieved.

[0072] Through case studies and calculations, it was found that the embankment structure of oil and gas pipelines can achieve energy neutralization, alleviate the problems of permafrost thawing and subsidence caused by hot oil pipelines and frost heave caused by gas pipelines, and improve the long-term stability of oil and gas pipelines in permafrost areas.

[0073] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "backfilling", and "laying" should be interpreted broadly, 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.

[0074] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. A method for intelligent control of oil and gas pipeline embankment structures in permafrost regions, characterized in that, include: The pipeline consists of a backfill layer (1), a pipeline protection layer (2), a crude oil pipeline (3), a gas pipeline (4), an intelligent control system (5), a fine sand layer (6), an insulation layer (7), a heat flow sensor (8), a drainage ditch (9), a permafrost layer (10), and a reference heat flow sensor (11). The crude oil pipeline (3) operates under positive temperature conditions, and the gas pipeline (4) operates under negative temperature conditions. The distance between the two pipelines is 2m, and their bottoms are on the same horizontal plane. The heat flow sensor (8) is installed inside the embankment to monitor the current heat flow value q in real time. The reference heat flow sensor (11) is buried 10 meters horizontally from the toe of the roadbed slope to monitor the reference heat flow value in that area. q t And use this as a preset threshold; including the following steps: S1, when the heat flow sensor detects the current heat flow value q Greater than the preset threshold q t When this occurs, an abnormal alarm is triggered; S2. Activate the intelligent control system to monitor the temperature of crude oil pipeline, gas pipeline and frozen soil. S3. Determine whether the temperature of the crude oil pipeline and gas pipeline is within the preset safe range; if the temperature is detected to be outside the safe range, trigger an abnormal alarm and start the cooling program. S4. Based on the heat released per unit length of crude oil pipeline Q 0 and the heat absorbed per unit length of the gas pipeline Q g Energy balance calculations are performed based on the energy balance relationship between them, and the operating temperature of the gas pipeline is adjusted to achieve this. Q 0 and Q g The heat released by the crude oil pipeline and the heat absorbed by the gas pipeline are equal, thus achieving dynamic neutralization, maintaining thermal balance and ensuring the stability of permafrost.

2. The intelligent control method for oil and gas pipeline embankment structures in permafrost regions according to claim 1, characterized in that: The insulation layer (7) is made of polyurethane foam material with a thermal conductivity of ≤0.03W / (m·℃) and a thickness of 10cm.

3. The intelligent control method for oil and gas pipeline embankment structures in permafrost regions according to claim 1, characterized in that: The heat flow sensor (8) is used to monitor the current heat flow value. q The formula is as follows: ； in q Heat flux value represents the amount of heat passing through a unit area per unit time. The temperature difference (°C) across the heat flow sensor. The thickness (m) on both sides of the heat flow sensor.

4. The intelligent control method for oil and gas pipeline embankment structures in permafrost regions according to claim 1, characterized in that, Current heat flux value q Greater than the preset threshold q t When the heat flux sensor malfunctions, an alarm is triggered, and the formula is: 。 5. The intelligent control method for oil and gas pipeline embankment structures in permafrost regions according to claim 1, characterized in that, Calculate the heat released per unit length of crude oil pipeline Q 0: ； Q 0: Heat per unit length released by the crude oil pipeline (W / m); T p Crude oil pipeline temperature (°C); T e : Temperature of frozen soil environment (°C); k s : Thermal conductivity of frozen soil (W / m·℃); r1: Radius of the outer wall of the crude oil pipeline (m); r2: Heat-affected radius of the crude oil pipeline (m).

6. The intelligent control method for oil and gas pipeline embankment structures in permafrost regions according to claim 1, characterized in that, Calculate the heat absorbed per unit length of the gas pipeline Q g : ； Q g Heat absorbed per unit length of gas pipeline (W / m); T g : Gas pipeline temperature (°C); T e : Temperature of frozen soil environment (°C); k s r3: Thermal conductivity of frozen soil (W / m·℃); r4: Radius of the outer wall of the gas pipeline (m); r5: Heat-affected radius of the gas pipeline (m).

7. The intelligent control method for oil and gas pipeline embankment structures in permafrost regions according to claim 1, characterized in that, Including heat released from crude oil pipelines Q 0 and the heat absorbed by the gas pipeline Q g equal: ； Expanding the formula, we get: ； The temperature of the gas pipeline can be obtained after simplification. T g : 。

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