Mixed transportation pipeline hydrate blocking risk grading method, device, medium and equipment

Abstract

The invention relates to a mixed transportation pipeline hydrate blockage risk grading method which comprises the following steps: determining the height of a sedimentary bed layer in a pipeline based on the hydrate generation deposition amount in the pipeline, and determining a hydrate blockage risk area and grade in the pipeline through an established hydrate blockage area judgment criterion. And finally, the hydrate blockage risk grading method in the mixed transportation pipeline is formed. According to the method, the risk of pipeline blockage can be comprehensively evaluated, the design optimization work of a pipeline transportation system is guided, and the method has important significance on hydrate flow safety guarantee.

Description

Technical Field

[0001] The invention relates to the technical field of pipeline safety control, and in particular to a method for grading hydrate blockage risks in a mixed transportation pipeline. Background Art

[0002] Due to the long distance, high pressure and low temperature of deepwater pipelines, hydrates, paraffin and other sediments are easily formed during operation, resulting in reduced pipeline transportation efficiency, increased transportation energy consumption, and even pipeline blockage leading to production interruption. Compared with other solid sediments, natural gas hydrates have become the most common and serious factor causing safety problems in deep-sea multiphase mixed transportation due to their rapid generation and high frequency of occurrence.

[0003] In recent years, many scholars have conducted relevant research on the risk of hydrate blockage in pipelines. However, the current research focuses on the relationship between the viscosity, pressure drop, hydrate volume fraction and other parameters of the fluid in the pipeline and the flow state of the fluid in the pipeline. However, there are still the following problems in determining the risk of hydrate blockage in pipelines and how to achieve hydrate risk control: (1) The study only focused on the numerous flow parameters in the pipeline and predicted the hydrate formation rate in the mixed pipeline, but did not make a corresponding prediction of the pipeline blockage risk based on the hydrate volume fraction; (2) The study only focused on one flow pattern and did not propose a hydrate blockage risk assessment method for mixed pipelines that includes multiple flow patterns; (3) The risk assessment method adopted by the research institute is relatively absolute or single. It only evaluates the blockage risk based on the amount of hydrate generated in the pipeline, and does not assess the risk level of different potential blockage risks according to different flow conditions of the pipeline. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide a mixed pipeline hydrate blockage risk classification method, which can comprehensively evaluate the risk of pipeline blockage, guide the design and optimization of the pipeline transportation system, and is of great significance to the safety of hydrate flow.

[0005] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for grading the risk of hydrate blockage in a mixed transportation pipeline, comprising the following steps: Obtain the basic parameters of the oil and gas mixed pipeline, monitor the operating status of the oil and gas mixed pipeline, obtain the operating parameters of the oil and gas mixed pipeline, determine the flow pattern of the oil and gas two phases in the oil and gas mixed pipeline, introduce different flow pattern models, determine the closed relationship formula of different flow patterns, and calculate the closed relationship parameters of the oil and gas mixed pipeline through the closed relationship formula of the corresponding flow pattern; Based on the closure relationship parameters and operation parameters of the oil and gas mixed pipeline, the hydrate flow model of the oil and gas mixed pipeline is used to calculate the phase parameters and hydrate generation amount at any time along the pipeline, and the hydrate deposition bed height is obtained; According to the hydrate bed height of the oil and gas mixed transportation pipeline, the flow state of the oil and gas mixed transportation pipeline and the flow area in which the flow state of the oil and gas mixed transportation pipeline is located are determined; Determine the hydrate blockage risk area and level of the oil and gas mixed pipeline according to the flow state and flow area of ​​the oil and gas mixed pipeline; According to the flow pattern of the oil and gas mixed pipeline and the hydrate blockage risk level, a pipeline blockage early warning plan is provided to form a complete and corresponding hydrate blockage risk classification method.

[0006] The mixed pipeline hydrate blockage risk classification method, preferably, the method for determining the flow pattern of the oil and gas two phases in the oil and gas mixed pipeline is: Based on the Taitel-Dukler flow pattern discrimination method, the flow judgment is performed. By detecting the fluid pressure, flow rate and inner diameter parameters in the pipeline, the velocity, viscosity and density of each phase are calculated, and then the Froude number and Loma number are calculated. Based on the Taitel flow pattern discrimination criterion, it is judged whether the fluid in the pipeline is in stratified flow or slug flow, and then the corresponding flow pattern models are imported respectively.

[0007] The mixed pipeline hydrate blockage risk classification method preferably includes the following steps: based on the closure relationship parameters and operation parameters of the oil and gas mixed pipeline, the parameters of each phase and the hydrate generation amount at any time along the pipeline are calculated through the oil and gas mixed pipeline hydrate flow model, and the hydrate deposition bed height is obtained. After the parameters of pressure, temperature, and gas-liquid phase flow in the oil-gas mixed pipeline are input into the hydrate flow model, the model calculates the hydrate volume fraction, and determines whether a moving bed and a fixed bed are generated in the pipeline based on the critical deposition velocity model and the limit suspension velocity model; when the flow velocity is low and less than the critical deposition velocity, a fixed hydrate bed exists in the pipeline; when the flow velocity is greater than the critical deposition velocity but less than the limit suspension velocity, a moving bed exists in the pipeline; when the flow velocity is greater than the limit suspension velocity, all hydrate particles in the pipeline float, and no deposition bed exists; The deposition velocity is determined by the following method: the parameters of gas-liquid phase velocity, density and gas-liquid phase ratio are processed into the hydrate deposition layer model, and the external forces acting on the hydrate particles at the bottom of the oil-gas mixed transmission pipeline are calculated, and the external forces include gravity, buoyancy, drag, lift, Baigno force, dissipation force, friction, hydrate bed pressure and particle-liquid bridge force; then the power and resistance acting on the hydrate particles are calculated in the force analysis, and when the resistance acting on the hydrate particles is greater than or equal to the power, the hydrate particles at the bottom of the oil-gas mixed transmission pipeline are stationary and become a fixed bed layer, and the velocity corresponding to the force balance is the critical deposition velocity; If there is a deposition bed, the particle settling velocity, shape factor, correction parameter are calculated through the incoming flow parameters, which include flow velocity, density, viscosity, pipe diameter, and the limiting suspension velocity is calculated; subsequently, the flow velocity is compared with the limiting suspension velocity. If the flow velocity is less than the limiting suspension velocity, there is a moving bed in the pipeline. At this time, the calculated parameters are input into the hydrate deposition bed height model corrected by fitting, the fluid Reynolds number and particle Reynolds number are calculated, and the hydrate deposition bed height is calculated.

[0008] The method for classifying the hydrate blockage risk of the multiphase transportation pipeline preferably determines the flow state of the oil-gas multiphase transportation pipeline and the flow region in which the flow state of the oil-gas multiphase transportation pipeline is located according to the hydrate bed height of the oil-gas multiphase transportation pipeline, and specifically includes the following steps: When there is a fixed bed in the pipeline, the hydrate volume fraction is high, the flow velocity is low, the formed hydrate bed height is very high, occupying most of the cross-sectional area of the pipeline, and the generated hydrate adheres to the pipe wall and remains stationary to form a fixed bed or flows along the pipeline in the form of a moving bed at a lower flow velocity. Then, the pipeline is extremely prone to blockage under such conditions, and this region is regarded as a dangerous flow region; When most of the hydrate particles in the pipeline are in a suspended flow state, no hydrate bed is formed or the formed moving bed height is very low, the pipeline will not be blocked under such conditions, and this region can be regarded as a safe flow region; When the pipeline is between the dangerous flow region and the safe flow region, it is an intermediate transition region. Although a hydrate bed will be formed, the bed height formed under the corresponding conditions is relatively low, and the corresponding pipeline blockage risk is also relatively low.

[0009] The method for classifying the hydrate blockage risk of the multiphase transportation pipeline preferably determines the hydrate blockage risk region and level of the oil-gas multiphase transportation pipeline according to the flow pattern and flow region of the oil-gas multiphase transportation pipeline, and specifically includes the following steps: The dangerous flow region is determined as the position where there is a hydrate blockage risk in the pipeline; After determining the position where there is a hydrate blockage risk in the pipeline, the hydrate bed height is judged. If the hydrate bed height H ≤ 0.15D, it is considered to be in a low-risk region. If 0.15D < H < 0.5D, it is considered to be in a medium-risk region. If 0.5D ≤ H ≤ D, it is considered to be in a high-risk region, where D is the pipeline diameter.

[0010] The method for classifying the hydrate blockage risk of the multiphase transportation pipeline preferably provides a pipeline blockage warning scheme according to the flow pattern of the oil-gas multiphase transportation pipeline and the hydrate blockage risk level, and specifically includes the following steps: It is difficult to form a hydrate blockage in a pipeline under low-risk conditions, so no corresponding measures need to be taken; When the hydrate blockage risk is medium or high, the probability of hydrate blockage in the pipeline increases greatly, so corresponding measures need to be taken to reduce the hydrate blockage risk; When the risk level of hydrate blockage is high, the pipeline is likely to have been blocked. At this time, the pipeline should be unblocked by decompression. When the hydrate blockage risk level is medium, it is necessary to adopt a risk control method, that is, to add hydrate kinetic inhibitors and anti-agglomeration agents to ensure that the hydrate slurry has good fluidity when hydrates are generated to prevent pipeline blockage.

[0011] The present invention also provides a mixed pipeline hydrate blockage risk classification device, comprising: The first processing unit is used to obtain basic parameters of the oil and gas mixed transmission pipeline, monitor the operation status of the oil and gas mixed transmission pipeline, obtain the operation parameters of the oil and gas mixed transmission pipeline, determine the flow pattern of the oil and gas two phases in the oil and gas mixed transmission pipeline, introduce different flow pattern models, determine the closed relationship formula of different flow patterns, and calculate the closed relationship parameters of the oil and gas mixed transmission pipeline through the closed relationship formula of the corresponding flow pattern; The second processing unit is used to calculate the parameters of each phase and the hydrate generation amount at any time along the pipeline through the hydrate flow model of the oil and gas mixed pipeline based on the closure relationship parameters and operation parameters of the oil and gas mixed pipeline, and obtain the hydrate deposition bed height; The third processing unit is used to determine the flow state of the oil and gas mixed transportation pipeline and the flow area in which the flow state of the oil and gas mixed transportation pipeline is located according to the hydrate bed height of the oil and gas mixed transportation pipeline; A fourth processing unit is used to determine the hydrate blockage risk area and level of the oil and gas mixed transportation pipeline according to the flow state and flow area of ​​the oil and gas mixed transportation pipeline; The fifth processing unit is used to provide a pipeline blockage warning plan according to the flow type of the oil and gas mixed transmission pipeline and the hydrate blockage risk level, so as to form a complete and corresponding hydrate blockage risk classification method.

[0012] The present invention also provides a computer storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the mixed pipeline hydrate blockage risk classification method are implemented.

[0013] The present invention also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the mixed pipeline hydrate blockage risk classification method when executing the computer program.

[0014] The present invention adopts the above technical solution, which has the following advantages: The hydrate blockage risk grading method for oil and gas mixed transportation pipelines provided by the present invention can grade the blockage risk of hydrates in different flow types according to the formation and deposition of hydrates in the pipeline, that is, based on the amount of hydrate formation and deposition in the pipeline, determine the height of the deposition bed in the pipeline, and determine the hydrate blockage risk area and level in the pipeline through the established hydrate blockage area determination criteria, ultimately forming a hydrate blockage risk grading method for mixed transportation pipelines.

[0015] The present invention defines the existence of a fixed bed in the pipeline as a dangerous flow area. The hydrate volume fraction is high, the flow velocity is low, and the height of the formed hydrate bed is very high, occupying most of the cross-sectional area of ​​the pipeline. The generated hydrate adheres to the pipe wall and remains motionless to form a fixed bed or flows along the pipeline in the form of a moving bed at a lower flow rate. The pipeline is very likely to be blocked when operating under this condition. When most of the hydrate particles in the pipeline are in a suspended flow state, no hydrate bed is formed or the height of the formed moving bed is very low, the pipeline will not be blocked when operating under this condition, and this area can be regarded as a safe flow area. When the pipeline is between the dangerous flow area and the safe flow area, it is an intermediate transition area. Although a hydrate bed will be formed, the height of the bed formed under the corresponding conditions is low, and the corresponding pipeline blockage risk is also low. Different risk levels are divided according to the blockage risk area, and corresponding hydrate blockage early warning measures under each level are further proposed.

[0016] The present invention uses the sediment bed height as a judgment factor and can reasonably and accurately assess and classify the pipeline blockage risk level.

[0017] In summary, the present invention has a very good effect on early warning and risk classification of pipelines in a hydrate blockage risk state. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a flow chart of a method for grading hydrate blockage risk in a mixed transportation pipeline provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0020] The present invention provides a method for grading the risk of hydrate blockage in a mixed transportation pipeline. Based on the amount of hydrate generated and deposited in the pipeline, the height of the deposited bed in the pipeline is determined. By establishing a hydrate blockage area judgment criterion, the hydrate blockage risk area and level in the pipeline are determined, and finally a method for grading the risk of hydrate blockage in a mixed transportation pipeline is formed.

[0021] like Figure 1 As shown, the method for grading the risk of hydrate blockage in mixed transportation pipelines provided by the present invention comprises the following steps: S1. Obtaining basic parameters of the oil-gas mixed transmission pipeline, monitoring the operation status in the oil-gas mixed transmission pipeline, obtaining the operation parameters of the oil-gas mixed transmission pipeline, determining the flow pattern of the oil and gas two-phase in the oil-gas mixed transmission pipeline, and introducing different flow pattern models, wherein the flow pattern model refers to a stratified flow model and a slug flow model based on a two-fluid model, determining the closed relationship formulas of different flow patterns, and calculating the closed relationship parameters of the oil-gas mixed transmission pipeline through the closed relationship formulas of the corresponding flow patterns; S2. Based on the closure relationship parameters and operation parameters of the oil and gas mixed transmission pipeline, the hydrate flow model of the oil and gas mixed transmission pipeline is used, wherein the hydrate flow model is the Englezos model, a hydrate formation kinetic model, to calculate the phase parameters (gas-liquid phase density, viscosity, gas consumption rate, hydrate formation rate, etc.) and hydrate formation amount at any time along the pipeline, and obtain the hydrate deposition bed height; S3, judging the flow state of the oil and gas mixed transportation pipeline and the flow area in which the flow state of the oil and gas mixed transportation pipeline is located according to the hydrate bed height of the oil and gas mixed transportation pipeline; Determine the hydrate blockage risk area and level of the oil and gas mixed pipeline according to the flow state and flow area of ​​the oil and gas mixed pipeline; S4. Provide a pipeline blockage warning plan based on the flow pattern of the oil and gas mixed pipeline and the hydrate blockage risk level to form a complete and corresponding hydrate blockage risk classification method.

[0022] In the above implementation, preferably, the method for determining the flow pattern of the oil and gas two phases in the oil and gas mixed pipeline is: Based on the Taitel-Dukler flow pattern discrimination method, the flow judgment is performed. By detecting the fluid pressure, flow rate and inner diameter parameters in the pipeline, the velocity, viscosity and density of each phase are calculated, and then the Froude number and Loma number are calculated. Based on the Taitel flow pattern discrimination criterion, it is judged whether the fluid in the pipeline is in stratified flow or slug flow, and then the corresponding flow pattern models are imported respectively.

[0023] In the above embodiment, preferably, based on the closure relationship parameters and operation parameters of the oil and gas mixed pipeline, the hydrate flow model of the oil and gas mixed pipeline is used to calculate the phase parameters and hydrate generation amount at any time along the pipeline, and obtain the hydrate deposition bed height, which specifically includes the following steps: After the parameters of pressure, temperature, and gas-liquid phase flow in the oil-gas mixed pipeline are input into the hydrate flow model, the model calculates the hydrate volume fraction, and determines whether a moving bed and a fixed bed are generated in the pipeline based on the critical deposition velocity model and the limit suspension velocity model; when the flow velocity is low and less than the critical deposition velocity, a fixed hydrate bed exists in the pipeline; when the flow velocity is greater than the critical deposition velocity but less than the limit suspension velocity, a moving bed exists in the pipeline; when the flow velocity is greater than the limit suspension velocity, all hydrate particles in the pipeline float, and no deposition bed exists; The deposition velocity is determined by the following method: the parameters of gas-liquid phase velocity, density and gas-liquid phase ratio are processed into the hydrate deposition layer model, and the external forces acting on the hydrate particles at the bottom of the oil-gas mixed transmission pipeline are calculated, and the external forces include gravity, buoyancy, drag, lift, Baigno force, dissipation force, friction, hydrate bed pressure and particle-liquid bridge force; then the power and resistance acting on the hydrate particles are calculated in the force analysis, and when the resistance acting on the hydrate particles is greater than or equal to the power, the hydrate particles at the bottom of the oil-gas mixed transmission pipeline are stationary and become a fixed bed layer, and the velocity corresponding to the force balance is the critical deposition velocity; If there is a sedimentation bed, the particle settling velocity and shape coefficient are calculated by inputting flow parameters, including flow velocity, density, viscosity, and pipe diameter, and the correction parameters are calculated to obtain the limiting suspension velocity. The flow velocity is then compared with the limiting suspension velocity. If the flow velocity is less than the limiting suspension velocity, there is a moving bed in the pipeline. At this time, the calculation parameters are input into the hydrate sedimentation layer height model that has been fitted and corrected, and the fluid Reynolds number and the particle Reynolds number are calculated to obtain the hydrate sedimentation bed height.

[0024] In the above embodiment, preferably, judging the flow state of the oil and gas mixed transportation pipeline and the flow region in which the flow state of the oil and gas mixed transportation pipeline is located according to the hydrate bed height of the oil and gas mixed transportation pipeline specifically includes the following steps: When there is a fixed bed in the pipeline, the hydrate volume fraction is high, the flow velocity is low, and the height of the formed hydrate bed is very high, occupying most of the cross-sectional area of ​​the pipeline. The generated hydrate adheres to the pipe wall and remains motionless to form a fixed bed or flows along the pipeline in the form of a moving bed at a lower flow rate. Under this condition, the pipeline is very likely to be blocked, and this area is considered a dangerous flow area; When most of the hydrate particles in the pipeline are in a suspended flow state, no hydrate bed is formed or the height of the formed moving bed is very low, the pipeline will not be blocked when running under this condition, and this area can be regarded as a safe flow area; When the pipeline is between the dangerous flow area and the safe flow area, it is an intermediate transition area. Although a hydrate bed will be formed, the bed height formed under the corresponding conditions is low, and the corresponding pipeline blockage risk is also low.

[0025] In the above embodiments, preferably, determining the hydrate plugging risk area and level of the oil-gas multiphase pipeline according to the flow state and flow region of the oil-gas multiphase pipeline specifically includes the following steps: Determine the positions in the pipeline where there is a risk of hydrate plugging as the dangerous flow regions; After determining the positions in the pipeline where there is a risk of hydrate plugging, judge the height of the hydrate bed. If the height of the hydrate bed H ≤ 0.15D, it is considered to be in a low-risk area. If 0.15D < H < 0.5D, it is considered to be in a medium-risk area. If 0.5D ≤ H ≤ D, it is considered to be in a high-risk area, where D is the pipeline diameter.

[0026] In the above embodiments, preferably, providing a pipeline plugging warning scheme according to the flow pattern of the oil-gas multiphase pipeline and the hydrate plugging risk level specifically includes the following steps: In pipelines under low-risk conditions, it is difficult to form hydrate plugs, so no corresponding measures need to be taken; When the hydrate plugging risk is medium or high level, the probability of hydrate plugging in the pipeline increases greatly, so corresponding measures need to be taken to reduce the hydrate plugging risk; When the hydrate plugging risk level is high, it is very likely that the pipeline has been plugged. At this time, the method of pressure reduction should be adopted to unblock the pipeline. When the hydrate plugging risk level is medium risk, the method of risk control needs to be adopted, that is, adding hydrate kinetic inhibitors and anti-agglomerants to ensure that the hydrate slurry has good fluidity in the case of hydrate formation and prevent the pipeline from being blocked.

[0027] Example 1: The method for judging the flow pattern of the pipeline described in step 1 is as follows: In the daily oil and gas production scenario, stratified flow and slug flow are mostly present in horizontal pipelines. By monitoring the operating parameters such as pressure and flow rate in the pipeline and pipeline parameters such as pipe diameter, it is judged whether the fluid in the pipeline is in stratified flow or slug flow, and then the corresponding models are run respectively.

[0028] In step 2, after inputting the parameters in the pipeline into the hydrate flow model, the model calculates the hydrate volume fraction. At this time, the critical deposition velocity is about 0.8 m / s, and the limit suspension velocity is about 1.2 m / s. It is judged whether a moving bed and a fixed bed are generated in the pipeline, and the height of the hydrate deposition bed is obtained.

[0029] In step 3, after calculation, it is judged that there is a fixed bed in the pipeline, the hydrate volume fraction is high, the flow velocity is low, and the height of the formed hydrate bed is very high, occupying most of the cross-sectional area of ​​the pipeline. The generated hydrate adheres to the pipe wall and remains stationary to form a fixed bed or flows along the pipeline in the form of a moving bed at a lower flow rate. The pipeline is very prone to blockage when operating under this condition, and some areas in the pipeline are in dangerous flow areas.

[0030] The hydrate deposition bed height in step 4 is 0.6D, and the blockage risk is graded as: high-risk area.

[0031] In step 5, after determining the hydrate blockage risk area and level, targeted early warning measures are provided.

[0032] When the hydrate blockage risk is at a medium or high level, the probability of hydrate blockage in the pipeline is greatly increased, so corresponding measures need to be taken to reduce the risk of hydrate blockage. When the hydrate blockage risk level is high, the pipeline is likely to have been blocked, and the decompression method should be used to unblock the pipeline. Since the decompression method will reduce the pipeline transportation capacity, reduce efficiency and even lead to the inability to complete production tasks, the decompression method is not used as a measure to reduce the blockage risk in medium and low risk situations. When the hydrate blockage risk level is medium risk, it is necessary to adopt a risk control method, that is, to add hydrate kinetic inhibitors and anti-agglomeration agents to ensure that the hydrate slurry has good fluidity in the case of hydrate formation to prevent pipeline blockage.

[0033] The present invention also provides a mixed pipeline hydrate blockage risk classification device, comprising: The first processing unit is used to obtain basic parameters of the oil and gas mixed transmission pipeline, monitor the operation status of the oil and gas mixed transmission pipeline, obtain the operation parameters of the oil and gas mixed transmission pipeline, determine the flow pattern of the oil and gas two phases in the oil and gas mixed transmission pipeline, introduce different flow pattern models, determine the closed relationship formula of different flow patterns, and calculate the closed relationship parameters of the oil and gas mixed transmission pipeline through the closed relationship formula of the corresponding flow pattern; The second processing unit is used to calculate the parameters of each phase and the hydrate generation amount at any time along the pipeline through the hydrate flow model of the oil and gas mixed pipeline based on the closure relationship parameters and operation parameters of the oil and gas mixed pipeline, and obtain the hydrate deposition bed height; The third processing unit is used to determine the flow state of the oil and gas mixed transportation pipeline and the flow area in which the flow state of the oil and gas mixed transportation pipeline is located according to the hydrate bed height of the oil and gas mixed transportation pipeline; A fourth processing unit is used to determine the hydrate blockage risk area and level of the oil and gas mixed transportation pipeline according to the flow state and flow area of ​​the oil and gas mixed transportation pipeline; The fifth processing unit is used to provide a pipeline blockage warning plan according to the flow type of the oil and gas mixed transmission pipeline and the hydrate blockage risk level, so as to form a complete and corresponding hydrate blockage risk classification method.

[0034] The present invention also provides a computer storage medium on which a computer program is stored. When the computer program is executed by a processor, the steps of the mixed pipeline hydrate blockage risk classification method are implemented.

[0035] The present invention also provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the mixed pipeline hydrate blockage risk classification method when executing the computer program.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for grading the risk of hydrate blockage in mixed transportation pipelines, characterized in that: The steps include: Obtain the basic parameters of the oil and gas mixed pipeline, monitor the operating status of the oil and gas mixed pipeline, obtain the operating parameters of the oil and gas mixed pipeline, determine the flow pattern of the oil and gas two phases in the oil and gas mixed pipeline, introduce different flow pattern models, determine the closed relationship formula of different flow patterns, and calculate the closed relationship parameters of the oil and gas mixed pipeline through the closed relationship formula of the corresponding flow pattern; Based on the closure relationship parameters and operation parameters of the oil and gas mixed pipeline, the hydrate flow model of the oil and gas mixed pipeline is used to calculate the phase parameters and hydrate generation amount at any time along the pipeline, and the hydrate deposition bed height is obtained; According to the hydrate bed height of the oil and gas mixed transportation pipeline, the flow state of the oil and gas mixed transportation pipeline and the flow area in which the flow state of the oil and gas mixed transportation pipeline is located are determined; Determine the hydrate blockage risk area and level of the oil and gas mixed pipeline according to the flow state and flow area of ​​the oil and gas mixed pipeline; According to the flow pattern of the oil and gas mixed pipeline and the hydrate blockage risk level, a pipeline blockage early warning plan is provided to form a complete and corresponding hydrate blockage risk classification method.

2. The method for grading the risk of hydrate blockage in mixed transportation pipelines according to claim 1 is characterized in that: The method for determining the flow pattern of the oil and gas two phases in the oil and gas mixed pipeline is: Based on the Taitel-Dukler flow pattern discrimination method, the flow judgment is performed. By detecting the fluid pressure, flow rate and inner diameter parameters in the pipeline, the velocity, viscosity and density of each phase are calculated, and then the Froude number and Loma number are calculated. Based on the Taitel flow pattern discrimination criterion, it is judged whether the fluid in the pipeline is in stratified flow or slug flow, and then the corresponding flow pattern models are imported respectively.

3. The method for grading hydrate blockage risk in mixed transportation pipelines according to claim 1, characterized in that: The method calculates the parameters of each phase and the amount of hydrate generated at any time along the pipeline through the hydrate flow model of the oil and gas mixed pipeline on the basis of the closure relationship parameters and the operation parameters of the oil and gas mixed pipeline, and obtains the height of the hydrate deposition bed, which specifically includes the following steps: After the parameters of pressure, temperature, and gas-liquid phase flow in the oil-gas mixed pipeline are input into the hydrate flow model, the model calculates the hydrate volume fraction, and determines whether a moving bed and a fixed bed are generated in the pipeline based on the critical deposition velocity model and the limit suspension velocity model; when the flow velocity is low and less than the critical deposition velocity, a fixed hydrate bed exists in the pipeline; when the flow velocity is greater than the critical deposition velocity but less than the limit suspension velocity, a moving bed exists in the pipeline; when the flow velocity is greater than the limit suspension velocity, all hydrate particles in the pipeline float, and no deposition bed exists; The deposition velocity is determined by the following method: the parameters of gas-liquid phase velocity, density and gas-liquid phase ratio are processed into the hydrate deposition layer model, and the external forces acting on the hydrate particles at the bottom of the oil-gas mixed transmission pipeline are calculated, and the external forces include gravity, buoyancy, drag, lift, Baigno force, dissipation force, friction force, hydrate bed pressure and particle-liquid bridge force; Then, the power and resistance of the hydrate particles are calculated in the force analysis. When the resistance of the hydrate particles is greater than or equal to the power, the hydrate particles at the bottom of the oil and gas mixed pipeline are stationary and become a fixed bed. The velocity corresponding to the force balance is the critical deposition velocity. If there is a deposition bed, the particle settling velocity, shape factor, correction parameter are calculated through the incoming flow parameters, which include flow velocity, density, viscosity, pipe diameter, and the limiting suspension velocity is obtained; subsequently, the flow velocity is compared with the limiting suspension velocity. If the flow velocity is less than the limiting suspension velocity, there is a moving bed in the pipeline. At this time, the calculated parameters are input into the hydrate deposition layer height model corrected by fitting, the fluid Reynolds number and particle Reynolds number are calculated, and the hydrate deposition bed height is obtained.

4. The method for grading hydrate blockage risk in mixed transportation pipelines according to claim 3 is characterized in that: Judging the flow state of the oil-gas multiphase transportation pipeline and the flow region in which the flow state of the oil-gas multiphase transportation pipeline is located according to the hydrate bed height of the oil-gas multiphase transportation pipeline specifically includes the following steps: When there is a fixed bed in the pipeline, the hydrate volume fraction is high, the flow velocity is low, the formed hydrate bed height is very high, occupying most of the pipeline cross-section area, and the generated hydrates adhere to the pipe wall and remain stationary to form a fixed bed or flow along the pipeline in the form of a moving bed at a lower flow velocity. In this case, the pipeline is extremely prone to blockage during operation, and this region is regarded as a dangerous flow region; When most of the hydrate particles in the pipeline are in a suspended flow state, no hydrate bed is formed or the formed moving bed height is very low, the pipeline will not be blocked during operation under this condition, and this region can be regarded as a safe flow region; When the pipeline is between the dangerous flow region and the safe flow region, it is an intermediate transition region. Although a hydrate bed will be formed, the bed height formed under the corresponding conditions is relatively low, and the corresponding pipeline blockage risk is also relatively low.

5. The method for grading hydrate blockage risk in mixed transportation pipelines according to claim 4, characterized in that: Determining the hydrate blockage risk region and level of the oil-gas multiphase transportation pipeline according to the flow state and flow region of the oil-gas multiphase transportation pipeline specifically includes the following steps: Determine the position where there is a hydrate blockage risk in the pipeline as the dangerous flow region; After determining the position where there is a hydrate blockage risk in the pipeline, judge the hydrate bed height. If the hydrate bed height H≤0.15D, it is considered to be in a low-risk region. If 0.15D<H<0.5D, it is considered to be in a medium-risk region. If 0.5D≤H≤D, it is considered to be in a high-risk region, where D is the pipeline diameter.

6. The method for grading hydrate blockage risk in mixed transportation pipelines according to claim 5, characterized in that: Providing a pipeline blockage warning scheme according to the flow pattern of the oil-gas multiphase transportation pipeline and the hydrate blockage risk level specifically includes the following steps: In a pipeline under low-risk conditions, it is difficult to form a hydrate blockage, so no corresponding measures need to be taken; When the hydrate blockage risk is medium or high level, the probability of hydrate blockage in the pipeline increases greatly, so corresponding measures need to be taken to reduce the hydrate blockage risk; When the hydrate blockage risk level is high, blockage is likely to have occurred in the pipeline. At this time, the method of pressure reduction should be adopted to unblock the pipeline. When the hydrate blockage risk level is medium risk, the method of risk control needs to be adopted, that is, adding hydrate kinetic inhibitors and anti-agglomerants to ensure that the hydrate slurry has good fluidity and prevent the pipeline from being blocked when hydrates are formed.

7. A mixed pipeline hydrate blockage risk classification device, characterized in that: Including: The first processing unit is used to obtain basic parameters of the oil and gas mixed transmission pipeline, monitor the operation status of the oil and gas mixed transmission pipeline, obtain the operation parameters of the oil and gas mixed transmission pipeline, determine the flow pattern of the oil and gas two phases in the oil and gas mixed transmission pipeline, introduce different flow pattern models, determine the closed relationship formula of different flow patterns, and calculate the closed relationship parameters of the oil and gas mixed transmission pipeline through the closed relationship formula of the corresponding flow pattern; The second processing unit is used to calculate the parameters of each phase and the hydrate generation amount at any time along the pipeline through the hydrate flow model of the oil and gas mixed pipeline based on the closure relationship parameters and operation parameters of the oil and gas mixed pipeline, and obtain the hydrate deposition bed height; The third processing unit is used to determine the flow state of the oil and gas mixed transportation pipeline and the flow area in which the flow state of the oil and gas mixed transportation pipeline is located according to the hydrate bed height of the oil and gas mixed transportation pipeline; A fourth processing unit is used to determine the hydrate blockage risk area and level of the oil and gas mixed transportation pipeline according to the flow state and flow area of ​​the oil and gas mixed transportation pipeline; The fifth processing unit is used to provide a pipeline blockage warning plan according to the flow type of the oil and gas mixed transmission pipeline and the hydrate blockage risk level, so as to form a complete and corresponding hydrate blockage risk classification method.

8. A computer storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the mixed pipeline hydrate blockage risk classification method according to any one of claims 1 to 6 are implemented.

9. A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the mixed pipeline hydrate blockage risk classification method according to any one of claims 1 to 6 are implemented.

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