Method and calculation system for determining the diffusion range of oil spill in oil pipeline with high and steep slope

Abstract

The present invention provides a method and a calculation system for determining the oil spill diffusion range of a high-steep slope oil pipeline. The method for determining the oil spill diffusion range of a high-steep slope oil pipeline comprises the steps of: determining the basic data of the area where the target section of the oil pipeline is located, calculating the vertical seepage distance of the oil product after the oil spill and diffusion occurs in the target section, and the oil spill area and oil spill distance of the oil product along the mountain surface, wherein the oil spill area and oil spill distance along the mountain surface of the oil product are calculated by the ZM model; and determining the control range of the oil spill diffusion of the target section according to the seepage distance, oil spill area and oil spill distance of the oil product. The oil spill diffusion range calculation system for the high-steep slope oil pipeline can realize the method for determining the oil spill diffusion range of the high-steep slope oil pipeline. The present invention has the advantages of high calculation accuracy, convenient on-site use, and the ability to plan and formulate management decisions based on the changing conditions of soils of different types of high-consequence sections on the entire oil pipeline.

Description

Technical Field

[0001] The invention relates to the technical field of oil pipeline protection, and in particular to a method and a calculation system for determining the oil spill diffusion range of an oil pipeline with a high and steep slope. Background Art

[0002] In recent years, many oil and gas pipelines in my country have been put into operation, and the number is growing rapidly. Their safe operation plays a vital role in national life and economic development. However, it is not difficult to find that the China-Myanmar Oil and Gas Pipeline under the jurisdiction of Southwest Pipeline Company is the "artery" to ensure the smooth operation of the social economy. The China-Myanmar Oil and Gas Pipeline crosses the Hengduan Mountains and the Yunnan-Guizhou Plateau, crosses international rivers such as the Lancang River and the Nujiang River, and passes through many Class IV areas. When the rainy season comes, it is very easy to cause geological disasters such as landslides or collapses, which will lead to pipeline damage. The safety and environmental risks are extremely high, and the difficulty of operation and maintenance is rare in the world. In addition, the China-Myanmar Pipeline also faces the following problems: (1) The contradiction between local economic development and pipeline protection is prominent; (2) There is a lack of effective detection methods for complex pipeline forces; (3) The inspection method is difficult to meet the requirements of weld quality control. These social and technical problems and the special geological and hydrological conditions of the China-Myanmar Pipeline seriously threaten the safe operation of the China-Myanmar Pipeline; (4) The terrain is undulating: there are many large drop sections, the oil leakage distance is far, and the impact range is large.

[0003] The publication number is "CN110070243A" and the name is "Oil Pipeline High Consequence Area Identification and Evaluation System and Method", which discloses the use of image recognition data obtained in the image processing module to extract the consequence element information data related to the pipeline high consequence area, and to grade and evaluate the severity of the consequences of the identified high consequence area according to the pre-set oil pipeline high consequence area identification and evaluation criteria, which can improve the recognition quality and efficiency. The publication number is "CN107862156A" and the name is "A Risk-Based Onshore Oil Pipeline Target Reliability Determination Method", which discloses the establishment of an onshore oil pipeline target reliability through a reasonable risk-based method, and realizes the optimization of the design and construction plan of the new oil pipeline based on the reliability method, so as to maintain a consistent risk level throughout the pipeline life cycle. The publication number "CN103994334B" and the name "Device and method for estimating leakage flow of oil pipelines based on KPCA-RBF curve fitting" discloses the use of KPCA kernel principal component analysis to effectively reduce the dimension of data with nonlinear relationships in oil pipelines, greatly reducing the number of principal component variables, reducing the development cycle and technical risks, and being more suitable for real-time data processing. The system has a clear division of system functions, which greatly improves the overall performance indicators of the system.

[0004] In summary, there is no calculation method for the oil spill range of high-steep slope oil pipelines in the prior art, and there is no pipeline control method based on the calculation of the oil spill range. By establishing a calculation method for the oil spill impact range in the high-consequence area of ​​high-steep slope oil pipelines, pipeline oil spills can be effectively intercepted and rescued, reducing the pollution of pipeline oil spills to water, soil and vegetation in the environment, and improving the control efficiency of oil pipelines. Summary of the invention

[0005] The purpose of the present invention is to solve at least one of the above-mentioned deficiencies in the prior art. For example, one of the purposes of the present invention is to provide a method for determining the oil spill diffusion range of a high-steep slope oil pipeline, which has high calculation accuracy, is easy to use on site, and can plan and formulate management decisions for the changing conditions of soils in different types of high-consequence sections of the entire pipeline. For another example, another purpose of the present invention is to provide a high-steep slope oil pipeline oil spill diffusion range calculation system that establishes a method for calculating the impact range of high-consequence areas of high-steep slope oil pipelines, so that the oil spill diffusion range is concretized.

[0006] In order to achieve the above object, the present invention provides a method for determining the diffusion range of oil spill in a high and steep slope oil pipeline, the method comprising the steps of:

[0007] Determine the basic data of the target section of the oil pipeline, calculate the vertical seepage distance of the oil after the target section of the pipeline spills and the oil spill area and distance along the mountain surface, where:

[0008] The oil spill area and oil spill distance along the mountain surface are calculated by formulas 1 and 2:

[0009] Formula 1 is:

[0010]

[0011] Where r is the radius of the liquid pool, m; t is the oil spill time, s; g is the gravitational acceleration, m / s 2 ; Δ is the proportion of the oil film thickness above the liquid surface, dimensionless is the mountain slope, °; is the angle of the diffusion sector area, °; Φ is the shape factor, which is related to the front oil film thickness h f It is related to the ratio of the average oil film thickness h and is dimensionless; C F is the friction resistance, m / s 2 ;

[0012] Formula 2 is:

[0013]

[0014] Among them, V pis the volume of oil in the liquid pool, m 3 ; t is the oil spill time, s; Q in,m is the mass leakage rate of oil, kg / s; ρ L is the density of the oil in the liquid pool, kg / m 3 ; Determine the control scope of oil spill diffusion in the target pipeline section based on the oil seepage distance, oil spill area and oil spill distance.

[0015] In an exemplary embodiment of the present invention, the method may further include using simulation software to perform unstructured grid division simulation verification on the target pipe section, simulating the oil spill area of ​​the target pipeline, comparing it with the calculated oil spill area, and correcting the calculation model.

[0016] In an exemplary embodiment of the present invention, the volume of the oil in the liquid pool can be calculated by Formula 3:

[0017] Formula 3 is:

[0018]

[0019] Among them, V p is the volume of oil in the liquid pool, m 3 ; A p is the liquid pool area, m 2 ; is the angle of the diffusion fan area, °; h is the height of the oil in the liquid pool, m; r is the radius of the liquid pool, m.

[0020] In an exemplary embodiment of the present invention, the vertical seepage distance of the oil product can be calculated by Formula 4:

[0021] Formula 4 is:

[0022]

[0023] Where θ is the volume oil content of the soil, %; H is the permeability coefficient, mm; t is the permeability time, s; α is the angle between the flow direction and the vertical direction, rad; K f is the unsaturated permeability coefficient, mm / s; S0 is the depth of oil penetration into the soil.

[0024] In an exemplary embodiment of the present invention, the formula 4 can be obtained by the following steps:

[0025] Oil spill penetration experiments were carried out on different types of soils, and the penetration depth and time of oil in different types of soils were recorded. The permeability coefficient, penetration time and penetration depth were fitted to obtain Equation 4.

[0026] In an exemplary embodiment of the present invention, the target pipe section may include different types of high consequence area pipes on an oil pipeline.

[0027] In an exemplary embodiment of the present invention, the method may further include the step of determining that the oil film stops spreading:

[0028] When the oil film thickness at the front position of the liquid pool is less than the critical thickness of the oil film, it is determined that the oil stops spreading;

[0029] The critical thickness of the oil film is calculated by equation 5 or 6:

[0030] Formula 5 is:

[0031]

[0032] Formula 6 is:

[0033]

[0034] Where σ is the surface tension of the liquid fuel, N / m; V L is the kinematic viscosity coefficient of liquid fuel, m 2 / s;h σ,f is the oil film thickness calculated by gravity-surface tension balance, mm; h c,f Oil film thickness calculated for gravity-viscous force balance, mm.

[0035] In an exemplary embodiment of the present invention, the basic data may include at least one of pipeline slope, oil viscosity, soil type, oil spill time and oil density, wherein:

[0036] The soil type may include at least one of rock, clay, medium sand, and gravel.

[0037] In an exemplary embodiment of the present invention, the method may further comprise the steps of:

[0038] The simulated diffusion area is compared with the calculated diffusion area to obtain the revised diffusion area calculation formula, where:

[0039] For soils mostly composed of rocks and clay, the formula 7 is used to calculate:

[0040] Formula 7 is:

[0041]

[0042] For soils with medium sand and gravel as the main components, we use formula 8 to calculate:

[0043] Formula 8 is:

[0044]

[0045] The present invention also provides a system for calculating the oil spill diffusion range of a high-steep slope oil pipeline, the calculation system comprising: a processor; and a memory storing a computer program, and when the computer program is executed by the processor, the method described above is implemented.

[0046] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0047] (1) A method for calculating the impact range of high-consequence areas in oil pipelines with steep slopes was established to specify the oil spill diffusion range;

[0048] (2) The calculation is highly accurate and easy to use on site, and can plan and make management decisions based on the changing conditions of different types of high-consequence pipe section soils throughout the pipeline;

[0049] (3) Pipelines can be controlled more reasonably and scientifically according to the spread of oil spills;

[0050] (4) Better control the scope of oil spills on the steep slopes of oil pipelines, reduce oil pollution to water, soil and vegetation in the environment, and improve control efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A grid model diagram of simulating slope oil pipeline leakage using fluent software according to an exemplary embodiment of the present invention is shown;

[0052] Figure 2 A cloud diagram of oil material leakage from a leak hole pipeline simulated by ANSYS according to an exemplary embodiment of the present invention is shown. DETAILED DESCRIPTION

[0053] Hereinafter, the method and calculation system for determining the oil spill diffusion range of a high and steep slope oil pipeline of the present invention will be described in detail in conjunction with the accompanying drawings and exemplary embodiments.

[0054] In a first exemplary embodiment of the present invention, a method for determining the diffusion range of oil spill in a high and steep slope oil pipeline comprises the steps of:

[0055] Determine the basic data of the area where the target section of the oil pipeline is located, such as the slope of the pipeline, the viscosity of the oil in the pipeline, the type of soil, etc. Calculate the vertical seepage distance of the oil after the oil spill occurs in the target section, as well as the oil spill area and oil spill distance along the mountain surface. Here, the oil spill distance refers to the longest distance of the liquid pool formed by the oil spill, and the oil spill area refers to the total area of ​​the liquid pool formed by the oil spill.

[0056] The oil spill area and oil spill distance along the mountain surface are calculated by formulas 1 and 2:

[0057] Formula 1 is:

[0058]

[0059] Where r is the radius of the liquid pool, m; t is the oil spill time, s; g is the gravitational acceleration, m / s 2 ; Δ is the proportion of the oil film thickness above the liquid surface, dimensionless is the mountain slope, °; is the angle of the diffusion sector area, °; Φ is the shape factor, which is related to the front oil film thickness h f It is related to the ratio of the average oil film thickness h and is dimensionless; C F is the friction resistance, m / s 2 Here, Δ=(ρ W -ρ L ) / ρ W Among them, ρ W is the density of water, kg / m 3 ρ L is the density of the liquid, kg / m 3 ; For oil spill on slope, Δ=1.

[0060] Formula 2 is:

[0061]

[0062] Among them, V p is the volume of oil in the liquid pool, m 3 ; t is the oil spill time, s; Q in,m is the mass leakage rate of oil, kg / s; ρ L is the density of the oil in the liquid pool, kg / m 3 .

[0063] The control scope of oil spill diffusion in the target pipeline section is determined based on the oil seepage distance, oil spill area and oil spill distance.

[0064] In this exemplary embodiment, the method may also include using simulation software to perform unstructured grid division simulation verification on the target pipe section, simulating the oil spill area of ​​the target pipeline, comparing it with the calculated oil spill area, and correcting the calculation model. For example, using fluent software to perform unstructured grid division simulation verification on the target pipe section, fitting the diffusion range of oil spills on high and steep slopes due to different soil types, thereby determining the control location of oil spills in the oil pipeline.

[0065] In this exemplary embodiment, the volume of the oil in the liquid pool can be calculated by Formula 3:

[0066] Formula 3 is:

[0067]

[0068] Among them, Vp is the volume of oil in the liquid pool, m 3 ; A p is the liquid pool area, m 2 ; is the angle of the diffusion fan area, °; h is the height of the oil in the liquid pool, m; r is the radius of the liquid pool, m.

[0069] Furthermore, the vertical seepage distance of the oil product can be calculated by Formula 4:

[0070] Formula 4 is:

[0071]

[0072] Where θ is the volumetric oil content of the soil, %; H is the permeability coefficient, mm; t is the permeability time, s; α is the angle between the flow direction and the vertical direction, rad. Since the model is a one-dimensional first-order partial derivative in the vertical direction, α = 0; K f is the unsaturated permeability coefficient, mm / s; S0 is the depth of oil penetration into the soil.

[0073] Further, the formula 4 can be obtained by the following steps:

[0074] Oil spill penetration experiments were carried out on different types of soils, and the penetration depth and time of oil in different types of soils were recorded. The permeability coefficient, penetration time and penetration depth were fitted to obtain Equation 4.

[0075] Specifically, the oil spill soil penetration experiment was used to determine the permeability of oil products in different types of soil. Crude oil and four types of loam, including rock, clay, medium sand, and gravel, were selected for the experiment. The indoor penetration test was used to study the effect of oil content on soil permeability, thereby analyzing the sensitivity of oil spills to soil. The relationship between the seepage coefficient and the seepage depth in the soil was fitted using MATLAB to obtain Equation 4.

[0076] In this exemplary embodiment, the target pipe sections may include different types of high consequence area pipes on an oil pipeline.

[0077] In this exemplary embodiment, the method may further include the step of determining that the oil film stops spreading:

[0078] When the oil film thickness at the front position of the liquid pool is less than the critical thickness of the oil film, it is determined that the oil stops spreading.

[0079] The critical thickness of the oil film is calculated by equation 5 or 6:

[0080] Formula 5 is:

[0081]

[0082] Formula 6 is:

[0083]

[0084] Where σ is the surface tension of the liquid fuel, N / m; V L is the kinematic viscosity coefficient of liquid fuel, m 2 / s;h σ,f is the oil film thickness calculated by gravity-surface tension balance, mm; h c,f is the oil film thickness calculated by gravity-viscous force balance, mm; the final critical value of the oil film thickness is h σ,f and h c,f Maximum value.

[0085] In this exemplary embodiment, the basic data may include at least one of pipeline slope, oil viscosity, soil type, oil spill time, and oil density. For example, the soil type may include at least one of rock, clay, medium sand, and gravel.

[0086] In this exemplary embodiment, the method may further include the steps of:

[0087] The simulated diffusion area is compared with the calculated diffusion area to obtain the revised diffusion area calculation formula, where:

[0088] For soils mostly composed of rocks and clay, the formula 7 is used to calculate:

[0089] Formula 7 is:

[0090]

[0091] For soils with medium sand and gravel as the main components, we use formula 8 to calculate:

[0092] Formula 8 is:

[0093]

[0094] In order to better understand the above exemplary embodiments of the present invention, they are further described below with reference to specific examples.

[0095] The technical solution adopted by the present invention mainly includes two steps:

[0096] 1. Analyze the impact of pipeline oil spill on soil, determine the permeability of oil in different soils through oil spill soil penetration experiments, and use MATLAB to fit the change formula of seepage coefficient and soil depth.

[0097] 2. Optimize the existing FERC model, consider the impact of mountain slope on oil diffusion, and obtain the ZM model that can describe the relationship between the oil spill area and oil spill distance of mountain oil pipelines and time and slope. Then use fluent software to simulate and verify the unstructured grid division of the target pipeline section, fit the diffusion range of oil spills on high and steep slopes due to different types of soil, and modify the ZM model to determine the control location of pipeline oil spills. Specifically:

[0098] (1) The oil spill soil penetration test was conducted to determine the permeability of oil products in different soils. Crude oil and loam were selected for the experiment. The effect of oil content on soil permeability was studied through indoor penetration tests. The sensitivity of oil spills to soil was analyzed. The results are shown in Table 1 below.

[0099] Table 1 Variation of the permeability coefficient of crude oil in four types of soil with time

[0100]

[0101] It can be seen from Table 1 that rocks are less polluted by crude oil and have the smallest infiltration depth, while gravel is more polluted by crude oil and has the greatest infiltration degree.

[0102] Using MATLAB to fit the relationship between the seepage coefficient and soil depth, we can get:

[0103]

[0104] Where θ is the volumetric oil content of the soil, %; H is the permeability coefficient, mm; t is the permeability time, s; α is the angle between the flow direction and the vertical direction, rad. Since the model is a one-dimensional first-order partial derivative in the vertical direction, α = 0; K f is the unsaturated permeability coefficient, mm / s; S0 is the depth of oil penetration into the soil.

[0105] (2) The FERC model is optimized to increase the impact of mountain slope on oil diffusion, and the ZM model is obtained to describe the relationship between the oil spill area and oil spill distance of mountain oil pipelines and time and slope.

[0106] The equation of motion is:

[0107]

[0108] Where r is the radius of the liquid pool, m; t is the oil spill time, s; g is the gravitational acceleration, m / s 2 ; Δ is the proportion of the oil film thickness above the liquid surface, dimensionless is the mountain slope, °; is the angle of the diffusion sector area, °; Φ is the shape factor, which is related to the front oil film thickness h fIt is related to the ratio of the average oil film thickness h and is dimensionless; C F is the friction resistance, m / s 2 Here, Δ=(ρ W -ρ L ) / ρ W Among them, ρ W is the density of water, kg / m 3 ρ L is the density of the liquid, kg / m 3 ; For oil spill on slope, Δ=1.

[0109] The mass equation is:

[0110]

[0111] Among them, V p is the volume of oil in the liquid pool, m 3 ; t is the oil spill time, s; Q in,m is the mass leakage rate of oil, kg / s; ρ L is the density of the oil in the liquid pool, kg / m 3 .

[0112] The volume of oil in the liquid pool can be calculated by the following formula:

[0113]

[0114] Among them, V p is the volume of oil in the liquid pool, m 3 ; A p is the liquid pool area, m 2 ; is the angle of the diffusion fan area, °; h is the height of the oil in the liquid pool, m; r is the radius of the liquid pool, m.

[0115] In the above ZM model, when the oil film thickness at the front position of the liquid pool is less than a critical value, the oil stops spreading. This critical value can be estimated by gravity-surface tension balance (Equation 5) or gravity-viscous force balance (Equation 6):

[0116]

[0117]

[0118] Where σ is the surface tension of the liquid fuel, N / m; V L is the kinematic viscosity coefficient of liquid fuel, m 2 / s;h σ,f is the oil film thickness calculated by gravity-surface tension balance, mm; h c,f is the oil film thickness calculated by gravity-viscous force balance, mm; the final critical value of the oil film thickness is hσ,f and h c,f Maximum value.

[0119] Since the China-Myanmar oil and gas pipeline of Southwest Pipeline Company passes through a wide area with rich soil types, when calculating oil spills on steep slopes, the FERC model is optimized to make the pipeline oil spill diffusion more consistent with the actual characteristics of high-consequence areas in the mountains. Therefore, the focus is on analyzing the oil spill diffusion range under different soils, so as to better target pipeline oil spill repair and management.

[0120] (3) Use Fluent software to perform unstructured grid division simulation verification, analyze the change of leakage volume with slope, and fit the oil spill diffusion range of different types of soil.

[0121] Figure 1 A grid model diagram of simulating slope oil pipeline leakage using fluent software according to an exemplary embodiment of the present invention is shown; Figure 2 A cloud diagram of oil material leakage from a leak hole pipeline simulated by ANSYS according to an exemplary embodiment of the present invention is shown.

[0122] like Figure 1 As shown in , the unstructured grid division simulation verification is performed using fluent software. The grid is imported into fluent. The soil parameters are shown in Table 2. The pipeline pressure is set to 5Mpa, 10Mpa, and 15Mpa. The leakage aperture is 10cm, the inclination angle is 10°, the pipeline inlet pressure is 10MPa, the outlet pressure is 9.6437MPa, the soil outlet pressure is standard atmospheric pressure, and the porosity is 0.4. The cloud of oil products leaking from the leakage hole pipeline is as follows: Figure 2 shown.

[0123] Table 2 Parameter settings of Fluent for simulating four different types of soil

[0124] Soil Type Permeability coefficient K (cm / s) 1 / α Porosity(%) rock <![CDATA[1×10 -4 ]]> <![CDATA[1.96×10 13 ]]> 20 clay <![CDATA[5×10 -4 ]]> <![CDATA[1×10 13 ]]> 35 medium sand <![CDATA[6×10 -3 ]]> <![CDATA[1.63×10 11 ]]> 40 Gravel <![CDATA[2.5×10 -2 ]]> <![CDATA[3.88×10 10 ]]> 50

[0125] The amount of oil spilled on different soil types calculated based on the FLUENT simulation is shown in Table 3 under the calculated formula and the simulated area.

[0126] Table 3 Oil spill diffusion area obtained by ZM model and fluent simulation for different soil types

[0127]

[0128]

[0129] According to the table above, there is a deviation between the calculated area and the simulated area ratio of the ZM model. The calculation formula of the ZM model needs to be corrected to achieve an oil spill diffusion range that conforms to the actual situation. According to matlab fitting, the correction coefficient is approximately equal to 1.088 when the porosity of rock and clay is small, and the correction coefficient is 0.980 when the porosity of medium sand and gravel is large. Therefore, the formula is corrected as follows:

[0130] (1) Mostly rocks and clay:

[0131]

[0132] (2) Medium sand, mostly gravel:

[0133]

[0134] The oil spill range of high and steep slopes can be calculated according to the above formula.

[0135] In a second exemplary embodiment of the present invention, a system for calculating the spread range of oil spill in a high and steep slope oil pipeline may include a processor and a memory. The memory is used to store a computer program. The computer program is executed by the processor so that the processor executes the computer program of the method for determining the spread range of oil spill in a high and steep slope oil pipeline of the first exemplary embodiment.

[0136] In summary, the beneficial effects of the present invention include at least one of the following:

[0137] (1) A method for calculating the impact range of high-consequence areas in oil pipelines with steep slopes was established to specify the oil spill diffusion range;

[0138] (2) The calculation is highly accurate and easy to use on site, and can plan and make management decisions based on the changing conditions of different types of high-consequence pipe section soils throughout the pipeline;

[0139] (3) Pipelines can be controlled more reasonably and scientifically according to the spread of oil spills;

[0140] (4) Better control the scope of oil spills on the steep slopes of oil pipelines, reduce oil pollution to water, soil and vegetation in the environment, and improve control efficiency.

[0141] Although the present invention has been described above in conjunction with the exemplary embodiments and the accompanying drawings, it should be apparent to those skilled in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.

Claims

1. A method for determining the diffusion range of oil spills in a high and steep slope oil pipeline, characterized in that: The method comprises the steps of: Determine the basic data of the target section of the oil pipeline, calculate the vertical seepage distance of the oil after the target section of the pipeline spills and the oil spill area and distance along the mountain surface, where: The vertical seepage distance of the oil product is calculated by formula 4: Formula 4 is: Where θ is the volume oil content of the soil, %; H is the permeability coefficient, mm; t is the permeability time, s; α is the angle between the flow direction and the vertical direction, rad; K f is the unsaturated permeability coefficient, mm / s; S0 is the depth of oil penetration into the soil; The oil spill area and oil spill distance along the mountain surface are calculated by formulas 1 and 2: Formula 1 is: Where r is the radius of the liquid pool, m; t is the oil spill time, s; g is the gravitational acceleration, m / s 2 ; Δ is the proportion of the oil film thickness above the liquid surface, dimensionless is the mountain slope, °; θ is the angle of the diffusion fan area, °; Φ is the shape factor, which is related to the front oil film thickness h f It is related to the ratio of the average oil film thickness h and is dimensionless; C F is the friction resistance, m / s 2 ; Formula 2 is: Among them, V p is the volume of oil in the liquid pool, m 3 ; t is the oil spill time, s; Q in,m is the mass leakage rate of oil, kg / s; ρ L is the density of the oil in the liquid pool, kg / m 3 ; The control scope of oil spill diffusion in the target pipeline section is determined based on the oil seepage distance, oil spill area and oil spill distance.

2. The method for determining the oil spill diffusion range of a high and steep slope oil pipeline according to claim 1 is characterized in that: The method also includes using simulation software to perform unstructured grid division simulation verification on the target pipe section, simulating the oil spill area of ​​the target pipeline, comparing it with the calculated oil spill area, and correcting the calculation model.

3. The method for determining the diffusion range of oil spill in a high and steep slope oil pipeline according to claim 1, characterized in that: The volume of the oil in the liquid pool is calculated by formula 3: Formula 3 is: V p =A p h=πr 2 θh / 360 Among them, V p is the volume of oil in the liquid pool, m 3 ; A p is the liquid pool area, m 2 ; θ is the angle of the diffusion fan area, °; h is the height of the oil in the liquid pool, m; r is the radius of the liquid pool, m.

4. The method for determining the diffusion range of oil spill in a high and steep slope oil pipeline according to claim 1, characterized in that: Formula 4 is obtained by the following steps: Oil spill penetration experiments were carried out on different types of soils, and the penetration depth and time of oil in different types of soils were recorded. The permeability coefficient, penetration time and penetration depth were fitted to obtain Equation 4.

5. The method for determining the diffusion range of oil spill in a high and steep slope oil pipeline according to claim 1, characterized in that: The target pipeline sections include different types of high-consequence area pipelines on the oil pipeline.

6. The method for determining the diffusion range of oil spill in a high and steep slope oil pipeline according to claim 1, characterized in that: The method further comprises the step of determining that the oil film stops spreading: When the oil film thickness at the front position of the liquid pool is less than the critical thickness of the oil film, it is determined that the oil stops spreading; The critical thickness of the oil film is calculated by equation 5 or 6, and the final critical value of the oil film thickness is h σ,f and h c,f The maximum value between Formula 5 is: Formula 6 is: Where σ is the surface tension of the liquid fuel, N / m; V L is the kinematic viscosity coefficient of liquid fuel, m 2 / s;h σ,f is the oil film thickness calculated by gravity-surface tension balance, mm; h c,f Oil film thickness calculated for gravity-viscous force balance, mm.

7. The method for determining the diffusion range of oil spill in a high and steep slope oil pipeline according to claim 1, characterized in that: The basic data includes at least one of pipeline slope, oil viscosity, soil type, oil spill time and oil density, wherein: The soil type includes at least one of rock, clay, medium sand and gravel.

8. The method for determining the diffusion range of oil spill in a high and steep slope oil pipeline according to claim 1, characterized in that: The method further comprises the steps of: The simulated diffusion area is compared with the calculated diffusion area to obtain the revised diffusion area calculation formula, where: For soils mostly composed of rocks and clay, the formula 7 is used to calculate: Formula 7 is: For soils with medium sand and gravel as the main components, we use formula 8 to calculate: Formula 8 is:

9. A system for calculating the oil spill diffusion range of a high and steep slope oil pipeline, characterized in that: The computing system comprises: A processor; and a memory storing a computer program, which, when executed by the processor, implements the method according to any one of claims 1 to 8.

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