A method for optimizing the topology of a gathering pipeline network in a mature oilfield

Abstract

The application provides a kind of old oil field regional gathering pipeline network topology optimization method, belongs to oil field gathering pipeline network engineering technical field.The technical scheme is: a kind of old oil field regional gathering pipeline network topology optimization method, with graph theory, gathering pipeline network is represented by connected graph, three-stage station distribution process is improved into series type oil gathering process, under the condition that the connection relationship of metering station and switching station is determined, with the shortest length between well station and pipeline, or the minimum flow distance and other targets, based on the basic idea of avoiding circle method, the optimal connected graph is calculated, the objective function is established, and compared with the existing pipeline network, the newly added pipeline network is determined, and combined with the existing pipeline network and technical and economic calculation method, the pipeline section to be built is screened out.The beneficial effects of the application are: solve the existing oil gathering pipeline network transportation direction existing detour, mixed liquid round trip transportation and other problems, can improve the connection mode of existing pipeline network, optimize the layout of pipeline network.

Description

Technical Field

[0001] This invention relates to the field of oilfield gathering and transportation pipeline engineering technology, and in particular to a method for optimizing the topology of regional gathering and transportation pipelines in old oilfields. Background Technology

[0002] Currently, oil and gas field gathering and transportation systems are a crucial component of oil and gas field production systems. These systems involve significant investment, high energy consumption, and high operating costs. Therefore, rational planning of oil and gas field gathering and transportation systems can effectively reduce construction costs and save energy. Existing oil and gas gathering and transportation pipeline systems mostly adopt a three-stage station layout process: oil and gas are first transported from the well site to a metering station, and then converged at the metering station to transfer stations and combined stations, forming a tree-like pipeline network. This results in detours in the pipeline transportation direction, causing repeated transport of mixed fluids, significant energy waste in gathering and transportation, and increased daily operating costs.

[0003] Currently, for oil wells in the late stages of production, the production volume is no longer measured by metering stations, but rather based on well dynamometer charts. Therefore, it is worth considering improving the "three-stage station deployment" process into a series oil gathering process, optimizing the connection between well sites and stations to reduce transportation distances and lower operating costs.

[0004] To address the issues of pipeline redundancy and irrational processes, the existing "three-level station layout process" needs to be modified. Given the current fixed layout of the branch and trunk pipeline networks, a new algorithm for generating the topology of the gathering and transportation pipeline network is proposed to determine the optimal connection and affiliation between oil wells and the branch and trunk pipeline networks, significantly shortening the distance between oil well transfer stations and eliminating pipeline redundancy and irrational processes. Summary of the Invention

[0005] To address the problems in the existing technology, the present invention aims to provide a method for optimizing the topology of the gathering and transportation pipeline network in old oilfields. This method addresses issues such as detours in the pipeline transportation direction and back-and-forth transport of mixed liquids in the oil gathering pipeline network, and proposes a new method for optimizing the topology of the gathering and transportation pipeline network in old oilfields. The goal is to improve the existing pipeline connection methods and optimize the pipeline layout.

[0006] This invention is achieved through the following technical solution: a method for optimizing the topology of a regional gathering and transportation pipeline in an old oilfield, comprising the following steps:

[0007] Step S1: Construct a connectivity diagram G1 based on the existing three-level pipeline network connecting the well site, transfer station, and metering station.

[0008] Step S2: Keep the connection between the transfer station and the metering station in G1 unchanged, optimize the connection between the well site and the transfer station and the metering station, so that the total length of the pipeline between the well stations is minimized, forming a series oil gathering process gathering and transportation network and constructing the connectivity diagram G2.

[0009] Step S3: Construct operation energy consumption correlation parameters based on each well site. The operation energy consumption correlation parameters are related to the operation energy consumption. The larger the operation energy consumption correlation parameter, the higher the operation energy consumption. If the increase in the operation energy consumption correlation parameter corresponding to the relevant well site of G2 compared to G1 exceeds a predetermined threshold, then delete the pipe segments connected to the relevant well site in G2.

[0010] Step S4: The pipe segments remaining in G2 in Step S3 form a new pipe segment connection graph G2'. Among them, G2' includes several connected components G2'. k Assume the number of connected components of G'2 is N. G ;

[0011] Step S5: Merge one connected component G2' in G2' k with G1 to form a new connected graph G3. k Calculate the annual operation cost C2 of the pipe network corresponding to G3. k Calculate the annual operation cost C1 of the pipe network corresponding to G1.

[0012] Step S6: Calculate the construction cost of the new pipe segments corresponding to G3 k and combine it with C2 to calculate the equivalent annual cost AC of G3. k Compare the magnitudes of C1 and AC. If AC < C1, then construct the new pipe segments corresponding to G3. k Otherwise, do not construct.

[0013] Step S7: Repeat Steps S5 - S6 until all connected components G2' i have been traversed, and then the pipe segments to be constructed can be determined from the new pipe segments in G2.

[0014] A graph can be described using a node set and an edge set. Described in mathematical language as G = (V, E), where V represents the node set and E represents the edge set. Under the condition that the connection relationship between metering stations and transfer stations is determined, take the shortest pipeline length or the minimum production distance sum between well stations as the objective f. Based on the basic idea of the loop avoidance method and the loop optimal condition, continuously make greedy selections in V - S to expand the set S until all well site nodes are included. Based on this optimal pipeline connection relationship, compare it with the existing pipeline connection relationship. Take certain operation energy consumption correlation parameters as the objective function (the set objective function can reflect transportation energy consumption and thus correlate with operation costs, such as the flow distance sum, etc.), screen the pipe segments to be constructed, and then use the methods of technical economics to judge which of the pipe segments to be constructed have economic benefits, and finally determine the pipe segments to be constructed.

[0015] Further, Step S2 is specifically as follows:

[0016] Establish a node set V using all nodes in G1, including nodes from transfer stations, metering stations, and all well sites; well sites are denoted as wells. k k represents the well site number, and the total number of well sites is denoted as N. well ;

[0017] Step S22: Establish node set S, which includes the set of all nodes with known connections; establish node set VS, which includes all well site nodes with unknown connections.

[0018] Step S23: Initialize the node set S, which initially contains only the nodes of the metering station and the transfer station, and establish a connected graph Gs based on the current connection relationship between the nodes in S, where Gs = (S, E) and E is the edge set.

[0019] Step S24: For the node set VS, establish the objective function matrix Matrix, where the elements of the objective function matrix Matrix are the shortest distances from each node in the node set VS to each edge in the edge set E.

[0020] Step S25: Find the minimum value f of all elements in the objective function matrix Matrix. min , the minimum value f min The corresponding edge E min Add Gs, and edge E min Add the corresponding non-S nodes to S;

[0021] Step S26, establish the new pipe segment edge set E new E min Place the newly added pipe segment edge set E new ;

[0022] Step S27: After each execution of steps S25-S26, node set S increases by one node, node set VS decreases by one node, Gs increases by one edge and one node, and E... new Add one edge accordingly;

[0023] Step S28, continue to calculate the connection between each node set in the updated node set VS and edge E. min The distance is calculated and updated to the objective function matrix Matrix;

[0024] Step S29: If S = V, then end the calculation process; otherwise, return to step S23.

[0025] In step S210, the final Gs is G2, which includes all nodes and is the connected graph with the shortest total length of pipelines between well sites.

[0026] Except for the first execution, step S24 is performed. According to step S28, subsequent calculations only need to be performed on the node set VS to edge E.min The distance is used to update the objective function matrix Matrix, which greatly reduces the amount of computation.

[0027] Based on the specific steps of step 2, it can be seen that the present invention is also applicable to the optimization of pipeline topology in the rolling development process of old oilfields. It can also connect the old blocks of old blocks and the new blocks of new blocks in the later stage of development of old oilfields, that is, add new well site nodes on the basis of the existing well station connection relationship, and connect them to the existing gathering and transportation pipeline network based on the principle of minimizing the objective function. The resulting connectivity graph G2 is also the best path and does not affect the subsequent judgment.

[0028] Considering the significantly shortened distance from the oil well to the transfer station, under a constant transfer station pressure, the wellhead back pressure can be reduced to some extent, thereby increasing the oil well production. Increasing the flow rate is naturally better, but actual operating energy consumption should also be considered. Operating energy consumption typically includes power losses due to friction and heat loss from the pipeline. Clearly, both are related to flow rate and distance; increasing either the flow rate or the distance will lead to increased operating energy consumption. However, due to pipeline optimization, well... k The flow rates in G1 and G2 will be different, which leads to the inconsistency between the trend of flow rate change and the trend of fluid path distance change. In order to comprehensively evaluate the trend of energy consumption change and to more accurately determine the necessity of constructing the corresponding pipeline section, the concept of flow rate distance sum is introduced. Whether the flow rate distance sum increases or decreases before and after pipeline optimization is an uncertain number, but the trend of the flow rate distance sum can directly reflect whether the operating energy consumption increases or decreases.

[0029] Furthermore, the operational energy consumption correlation parameters are for each well site. k The sum of flow distances to the transfer station, where the sum of flow distances is the well site. k Fluid flow rate Q k Distance L from the fluid path k The product of is denoted as F. k =Q k ×L k L k Indicates well site k The fluid path distance from the fluid to the transfer station, Q k Indicates well site k Traffic, F k The larger the value, the higher the energy consumption; step S3 specifically involves:

[0030] Step S31, corresponding to the connected graph G1, calculate the wells for each well site. k The fluid path distance to the transfer station is L1. k and well site k Flow Q1 in G1 kThen each well site in G1 k Corresponding F1 k =Q1 k ×L1 k :

[0031] Step S32, corresponding to the connected graph G2, calculate the wells for each well site. k The fluid path distance to the transfer station is L2. k and well site k Traffic in G2 Q2 k Then each well site in G2 k The corresponding F2 k =Q2 k ×L2 k ;

[0032] Step S33, compare F2 in G2 and G1. k With F1 k Let the magnitude be denoted as ΔF. k =F2 k –F1 k Set and change the threshold ΔF critical If ΔF k <ΔF critical Then keep E new Zhongyu Well Site k The newly added pipe section is connected; if ΔF k ≥ΔF critical Then delete E. new Zhongyu Well Site k Newly added pipe sections connected to the pipeline;

[0033] ΔF critical The setting should be based on the actual needs and does not necessarily have to be zero.

[0034] Furthermore, the calculation process for annual operating expenses C1 and C2 in step S5 is as follows:

[0035] Step S51, calculate the annual operating cost of pipe segment j as C. j Operating costs C j Including the cost of heat loss due to heat dissipation in the pipeline S R,j and the power loss fee S caused by friction loss P,j ;

[0036] Heat loss fee S R,j Specifically:

[0037]

[0038] Where T S,j - The starting temperature of pipe section j, T E,j- The end temperature of pipe segment j, Q j Let ρ be the flow rate of pipe segment j. j - Fluid density of pipe section j, kg / m 3 C y - Specific heat capacity of oil at the average oil temperature of pipe section j, kJ / (kg·℃); e y - Fuel oil price, yuan / ton; B H - Fuel oil calorific value, kJ / kg; η R - Heating furnace efficiency;

[0039] Power loss cost S P,j Specifically:

[0040]

[0041] Among them, H j - Pressure drop in pipe section j, m; e d - Electricity price, yuan / (kW·h); η pe - Pump unit efficiency;

[0042] Step S52: Calculate the operating energy consumption C of pipe segment j. j :C j =S R,j +S P,j The annual operating cost of the entire pipeline network is the sum of the operating energy consumption of all pipeline segments, denoted as C = ∑C j ;

[0043] Step S53: Based on step S52, calculate the annual operating cost C1 corresponding to G1 and G3. k The corresponding annual operating cost C2;

[0044] Furthermore, the flow rate Q of pipe segment j j The calculation steps are as follows:

[0045] Step S511, record Q k,j for well site k The flow rate of the fluid passing through pipe section j in the well site; k If the fluid flows through pipe section j, then Q k,j =q k q k Corresponding well site k The flow rate; if the well site k If the fluid does not flow through pipe section j, then Q k,j =0;

[0046] In step S512, the flow rate Q of pipe segment j is... j for:

[0047] Further, step S6 is specifically as follows:

[0048] Step S61, consider the construction cost of the newly added pipeline segments in G3 k and calculate the equivalent annual cost AC of the entire pipeline network of G3 k The expression of the equivalent annual cost AC is:

[0049]

[0050] Where: I is the total annual investment (including fixed asset investment and working capital); C is the annual operating cost; SV is the residual value of fixed assets recovered at the end of the calculation period; W is the working capital recovered at the end of the calculation period; N is the calculation period; i is the financial benchmark rate of return of the petroleum industry i C (when conducting financial evaluation); (P / F, i, t) = (1 + i) -t is the single-payment present worth factor, or discount factor, discount coefficient; (A / P, i, N) = i(1 + i) N [(1 + i) N -1] -1 is the capital equal recovery factor;

[0051] Step S62, compare C1 and AC. If AC < C1, construct the corresponding newly added pipeline segments; otherwise, do not construct.

[0052] Further, the total annual investment I is the cost of the newly built pipeline segments in G3 k specifically: I = B × L G3,k ; where L G3,k is the total length of the newly built pipeline segments in the connected component G3 k and B is the cost per meter of the pipeline.

[0053] Further, assume that the corresponding newly added pipeline in G3 k is completed and put into operation in the current year, and the working capital and residual value of fixed assets recovered at the end of the calculation period are not considered. Then the equivalent annual cost AC of the corresponding G3 k can be simplified to:

[0054] AC = C2 + B × L G3,k × (A / P, i, N).

[0055] The beneficial effects of the present invention are as follows: The present invention can solve problems such as the detour of the oil gathering pipeline transportation direction and the round-trip transportation of the mixed liquid in the existing oil gathering pipeline network, can improve the existing pipeline network connection method, and optimize the pipeline network layout; the present invention has strong operability, combines the path optimization algorithm with technical and economic means, improves based on the existing conditions of the current oil gathering pipeline network, reduces costs to the greatest extent, improves economic benefits, and is more in line with actual operation; the improved gathering and transportation pipeline network using the present invention can also reduce the wellhead back pressure and increase the liquid production of oil wells to a certain extent. Attached Figure Description

[0056] Figure 1 G1 is the connectivity diagram corresponding to the three-level oil gathering pipeline network of well site, metering station and transfer station.

[0057] Figure 2 The initial connected graph G corresponding to the connection relationship between the metering station and the transfer station. S .

[0058] Figure 3 To optimize the connection diagram G2 corresponding to the series oil gathering process pipeline network of the well site, metering station and transfer station. Detailed Implementation

[0059] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0060] A graph can be described using a set of nodes and a set of edges, mathematically represented as G = (V, E), where V represents the set of nodes and E represents the set of edges. Given a defined connection between metering stations and transfer stations, the goal is to minimize the pipeline length between well sites or the sum of flow distances. Based on the basic idea of ​​the loop avoidance method and the optimal loop condition, greedy choices are made continuously in VS to expand the set S, ultimately encompassing all well site nodes. Based on this optimal pipeline connection, it is compared with existing pipeline connections. Certain operational energy consumption parameters are used as objective functions (the set objective function reflects transportation energy consumption and thus relates to operating costs, such as the pipeline length or the sum of flow distances between well sites) to screen for potential pipeline segments. Then, techno-economic methods are used to determine which segments are more economically viable, ultimately identifying the segments to be constructed.

[0061] Figure 1 For the connectivity diagram G1 corresponding to the three-level oil gathering pipeline network of well site, metering station and transfer station, from Figure 1 As can be seen from the existing gathering and transportation process, some single wells exhibit a phenomenon of pipeline reversal. Figure 2 The initial connected graph G corresponding to the connection relationship between the metering station and the transfer station. S . Figure 3 This is the connectivity diagram G2 corresponding to the optimized series-connected oil gathering pipeline network of well sites, metering stations, and transfer stations. The numerous "X"s in the diagram represent the distribution of oil wells, with each X representing a well site node. The "dots" in the diagram represent metering stations, and the single "square" represents a transfer station. For example... Figure 1 As shown, the oilfield has a total of 135 wells, 15 metering stations, and 1 transfer station. Before optimization, the total distance between all well sites and the "Metering Station and Transfer Station Connection Diagram" was 31,523m.

[0062] See Figures 1-3Example 1: This invention is achieved through the following technical solution: a method for optimizing the topology of a regional gathering and transportation pipeline in an old oilfield, comprising the following steps:

[0063] Step S1: Based on the existing three-level station layout process pipeline network, construct the connection diagram G1 of the gathering and transportation pipeline network between the well site, transfer station and metering station;

[0064] Step S2: Keep the connection between the transfer station and the metering station in G1 unchanged, optimize the connection between the well site and the transfer station and the metering station, so that the total length of the pipeline between the well stations is minimized, forming a series oil gathering process gathering and transportation network and constructing the connectivity diagram G2. Figure 3 To optimize the connection relationship between the well site, metering station and transfer station, the connection graph G2 is used as the optimal serial gathering and transportation network connection graph, and also serves as the basis for subsequent optimization steps.

[0065] Step S2 specifically involves:

[0066] Step S21: Establish a node set V using all nodes in G1, including nodes from the transfer station, metering station, and all well sites; well sites are denoted as wells. k k represents the well site number, and the total number of well sites is denoted as N. well ;

[0067] Step S22: Establish node set S, which includes the set of all nodes with known connections; establish node set VS, which includes all well site nodes with unknown connections.

[0068] Step S23: Initialize the node set S, which initially contains only the nodes of the metering station and the transfer station, and establish a connected graph Gs based on the current connection relationship between the nodes in S, where Gs = (S, E) and E is the edge set.

[0069] Step S24: For the node set VS, establish the objective function matrix Matrix, where the elements of the objective function matrix Matrix are the shortest distances from each node in the node set VS to each edge in the edge set E.

[0070] Step S25: Find the minimum value f of all elements in the objective function matrix Matrix. min , the minimum value f min The corresponding edge E min Add Gs, and edge E min Add the corresponding non-S nodes to S;

[0071] Step S26, establish the new pipe segment edge set E new E min Place the newly added pipe segment edge set E new ;

[0072] Step S27: Each time S25-S26 is executed, node set S increases by one node, node set VS decreases by one node, Gs increases by one edge and one node, and E... new Add one edge accordingly;

[0073] Step S28, continue to calculate the connection between each node set in the updated node set VS and edge E. min The distance is calculated and updated to the objective function matrix Matrix;

[0074] Step S29: If S = V, then end the calculation process; otherwise, return to step S23.

[0075] In step S210, the final Gs is G2, which includes all nodes and is the connected graph with the shortest total length of pipelines between well sites.

[0076] Except for the first execution, step S24 is performed. According to step S28, subsequent calculations only need to be performed on the node set VS to edge E. min The distance is used to update the objective function matrix Matrix, significantly reducing the computational workload.

[0077] Step S3: Construct operational energy consumption correlation parameters based on each well site. These parameters are related to operational energy consumption; a larger parameter indicates higher operational energy consumption. If the increase in the operational energy consumption correlation parameter for the corresponding well site in G2 exceeds a predetermined threshold compared to G1, then delete the pipe segment in G2 connected to the corresponding well site. Considering the significantly shortened distance from the oil well to the transfer station, under a constant transfer station pressure, the wellhead back pressure can be reduced to a certain extent, thereby increasing the oil well production. Increasing the flow rate is naturally better, but actual operational energy consumption should also be considered. Operational energy consumption typically includes power loss due to friction and heat dissipation loss from the pipeline. Obviously, both are related to flow rate and distance; increasing either the flow rate or the distance will lead to an increase in operational energy consumption. However, due to pipeline optimization, well... k The flow rates in G1 and G2 will change. Generally, a shorter distance will reduce wellhead back pressure and increase well production to some extent. This leads to a discrepancy between the flow rate change trend and the fluid path distance change trend. To comprehensively assess energy consumption trends and more accurately determine the necessity of constructing corresponding pipeline sections, the concept of flow rate plus distance is introduced. Whether the flow rate plus distance increases or decreases before and after pipeline optimization is uncertain, but the trend of the flow rate plus distance directly reflects whether operational energy consumption increases or decreases. The operational energy consumption correlation parameters are for each well site. k The sum of flow distances to the transfer station, where the sum of flow distances is the well site. k Fluid flow rate Q k Distance L from the fluid pathk The product of is denoted as F. k =Q k ×L k L k Indicates well site k The fluid path distance from the fluid to the transfer station, Q k Indicates well site k Traffic, F k The larger the value, the higher the energy consumption; step S3 specifically involves:

[0078] Step S31, corresponding to the connected graph G1, calculate the wells for each well site. k The fluid path distance to the transfer station is L1. k and well site k Flow Q1 in G1 k Then each well site in G1 k Corresponding F1 k =Q1 k ×L1 k :

[0079] Step S32, corresponding to the connected graph G2, calculate the wells for each well site. k The fluid path distance to the transfer station is L2. k and well site k Traffic in G2 Q2 k Then each well site in G2 k The corresponding F2 k =Q2 k ×L2 k ;

[0080] Step S33, compare F2 in G2 and G1. k With F1 k Let the magnitude be denoted as ΔF. k =F2 k –F1 k Set and change the threshold ΔF critical If ΔF k <ΔF critical Then keep E new Zhongyu Well Site k The newly added pipe section is connected; if ΔF k ≥ΔF critical Then delete E. new Zhongyu Well Site k Newly added pipe sections connected to the pipeline;

[0081] Step S33, compare F2 in G2 and G1. i With F1 i Let the magnitude be denoted as ΔF. i= F2 i – F1 i ; Set the change threshold ΔF critical ;

[0082] If ΔL i <ΔF critical , then retain the new added pipe segment E in E new connected to the wellsite well i ; new,i ;

[0083] If ΔL i ≥ΔF critical , then delete the new added pipe segment E in E new connected to the wellsite well i ; new,i .

[0084] ΔF critical should be set according to the on-site requirements and is not necessarily zero.

[0085] Step S4. The pipe segments retained by G2 in step S3 form the new added pipe segment connectivity graph G2', where G2' includes several connected components G2' k . Assume the number of connected components of G′2 is N G ; N G is equal to the number of pipe segments connected to the initialized Gs.

[0086] Step S5. Merge one connected component G2' in G2' k with G1 to form a new connectivity graph G3 k . Calculate the annual operation cost C2 of the pipe network corresponding to G3 k ; Calculate the annual operation cost C1 of the pipe network corresponding to G1;

[0087] Step S6. Calculate the construction cost of the corresponding new added pipe segments in G3 k and combine it with C2 to calculate the equivalent annual cost AC of G3 k . Compare the magnitudes of C1 and AC. If AC < C1, then construct the corresponding new added pipe segments in G3 k , otherwise do not construct;

[0088] Step S7. Repeat steps S5 - S6 until all connected components G2' k have been traversed, and the pipe segments to be constructed can be determined from the new added pipe segments in G2.

[0089] Relative to Figure 1The total distance of the optimized gathering and transportation pipeline network G2 is only 9573.4m, and the distance of the oil gathering pipeline network is shortened by more than 2 / 3. This can significantly shorten the distance of oil well fluid to the transfer station and eliminate the detour phenomenon and the problem of back-and-forth transportation of mixed liquid in the old oilfield gathering and transportation pipeline network.

[0090] Example 2:

[0091] Based on Example 1, in order to be more objective and closer to actual operation, and to simplify the technical and economic calculation process, steps S5 and S6 are refined as follows:

[0092] The calculation process for annual operating costs C1 and C2 in step S5 is as follows:

[0093] Step S51, calculate the annual operating cost of pipe segment j as C. j Operating costs C j Including the cost of heat loss due to heat dissipation in the pipeline S R,j and the power loss fee S caused by friction loss P,j ;

[0094] Heat loss fee S R,j Specifically:

[0095]

[0096] Where T S,j - The starting temperature of pipe section j, T E,j - The end temperature of pipe segment j, Q j Let ρ be the flow rate of pipe segment j. j - Fluid density of pipe section j, kg / m 3 C y - Specific heat capacity of oil at the average oil temperature of pipe section j, kJ / (kg·℃); e y - Fuel oil price, yuan / ton; B H - Fuel oil calorific value, kJ / kg; η R - Heating furnace efficiency;

[0097] Power loss cost S P,j Specifically:

[0098]

[0099] Among them, H j - Pressure drop in pipe section j, m; e d - Electricity price, yuan / (kW·h); η pe - Pump unit efficiency;

[0100] Step S52: Calculate the operating energy consumption C of pipe segment j. j :C j =SR,j +S P,j The annual operating cost of the entire pipeline network is the sum of the operating energy consumption of all pipeline segments, denoted as C = ∑C j ;

[0101] Step S53: Based on step S52, calculate the annual operating cost C1 corresponding to G1 and G3. k The corresponding annual operating cost C2;

[0102] The flow rate Q of pipe segment j j The calculation steps are as follows:

[0103] Step S511, record Q k,j for well site k The flow rate of the fluid passing through pipe section j in the well site; k If the fluid flows through pipe section j, then Q k,j =q k q k Corresponding well site k The flow rate; if the well site k If the fluid does not flow through pipe section j, then Q k,j =0;

[0104] In step S512, the flow rate Q of pipe segment j is... j for:

[0105] Step S6 specifically involves:

[0106] Step S61, consider G3 k The construction cost of the newly added pipeline section is calculated for G3. k The equivalent annual cost AC for the entire pipeline network; the expression for the equivalent annual cost AC is:

[0107]

[0108] Where: I represents total annual investment (including fixed asset investment and working capital); C represents annual operating costs; SV represents the residual value of fixed assets recovered at the end of the calculation period; W represents the working capital recovered at the end of the calculation period; N represents the calculation period; and i represents the benchmark rate of return for the petroleum industry. C (In financial evaluation); (P / F,i,t)=(1+i) -t This is the present value factor for a single payment, or the discount factor; (A / P,i,N)=i(1+i) N [(1+i) N -1] -1 This is the coefficient for equal capital recovery;

[0109] Step S62: Compare C1 and AC. If AC < C1, construct the corresponding new pipeline segment; otherwise, do not construct.

[0110] The total annual investment I is G3 k The cost of the newly built pipeline segment in it is specifically: I = B × L G3,k ; where L G3,k is the total length of the newly built pipeline segment in the connected component G3 k and B is the cost per meter of the pipeline.

[0111] Assume that the corresponding new pipeline in G3 k is completed and put into operation in the current year. Without considering the recovered working capital and the residual value of fixed assets at the end of the calculation period, the equivalent annual cost AC of the corresponding G3 k can be simplified as:

[0112] AC = C2 + B × L G3,k × (A / P, i, N).

[0113] Embodiment 3:

[0114] Whether in Embodiment 1 or Embodiment 2, according to the specific steps of the said Step S2, it can be seen that the present invention is also applicable to the optimization of the pipeline network topology structure in the rolling development of old oilfields, and can also connect the infill wells in the old blocks and the new wells in the new blocks in the later stage of old oilfield development, that is, on the basis of the existing connection relationship of well stations, add new well site nodes, and connect them to the existing gathering and transportation pipeline network based on the principle of minimizing the objective function. The obtained connected graph G2 is also the optimal path and does not affect the subsequent judgment.

[0115] The present invention can solve the problems such as the detour in the pipeline transportation direction of the existing oil gathering pipeline network and the round-trip transportation of the mixed liquid, can improve the existing pipeline network connection method, and optimize the pipeline network layout; the present invention has strong operability, combines the path optimization algorithm with technical and economic means, improves based on the existing conditions of the current oil gathering pipeline network, reduces the cost to the greatest extent, improves the economic benefits, and is more in line with the actual operation.

[0116] The technical features not described in the present invention can be realized by or adopted the existing technology, and will not be elaborated here. Of course, the above description is not a limitation to the present invention, and the present invention is not limited to the above examples. The changes, modifications, additions or substitutions made by those of ordinary skill in the art within the essence of the present invention should also belong to the protection scope of the present invention.

Claims

1. A method for optimizing the topology of a regional gathering and transportation pipeline network in an old oilfield, characterized in that, Includes the following steps: Step S1: Construct a connectivity diagram G1 based on the existing three-level pipeline network connecting the well site, transfer station, and metering station. Step S2, hold G The connection between the transfer station and the metering station in section 1 remains unchanged. The connection between the well site and the transfer station and metering station is optimized to minimize the total length of the pipeline between well stations, forming a series oil gathering process network and constructing a connectivity diagram. G 2; Step S3: Construct operational energy consumption correlation parameters based on each well site. These parameters are related to operational energy consumption; a larger parameter indicates higher operational energy consumption. G 2 compared to G 1. If the increase in the corresponding operating energy consumption-related parameter for the well site exceeds a predetermined threshold, then delete the operation. G 2. Pipe sections connected to the corresponding well sites; In step S4, in step S3 G 2. The retained pipe segments form the connection diagram of the newly added pipe segments. G 2', where G 2' includes several connected components. G 2' k ; Step S5, G A connected component in 2' G 2' k and G 1. Merge to form a new connected graph. G 3 k Calculate G 3 k Annual operating cost of the corresponding pipeline network C 2. Calculate the annual operating cost of the pipeline network corresponding to G1. C 1; Step S6, Calculation G 3 k The construction cost of the corresponding new pipeline section and in combination C 2. Calculation G 3 k Equal annual fees AC ;Compare C 1 and AC The size, if AC < C 1. Construction G 3 k The corresponding new pipeline section will be constructed if the other section is not included; otherwise, no new pipeline section will be constructed. Step S7: Repeat steps S5-S6 until all connected components are connected. G 2' k All have been traversed, so we can start from... G The sections to be constructed were identified from the newly added pipe sections in section 2; Specifically, step S2 is as follows: Step S21, with G All nodes in 1 establish a node set V This includes transfer stations, metering stations, and all nodes at the well site; the well site is denoted as well. k , k This indicates the well site number; the total number of well sites is denoted as [number]. N well ; Step S22, establish a node set S This includes the set of all nodes whose connections have been established; establishing the node set. V - S This includes all well site nodes with undetermined connections; Step S23, initialize the node set S , S Initially, it only includes nodes for metering stations and transfer stations, and according to... S Establish a connected graph based on the current connections between all nodes. Gs , Gs =( S , E ),in E It is an edge set; Step S24, for the node set V - S Establish an objective function matrix Matrix, where the elements of the objective function matrix Matrix are node sets. V - S Each node in the set of edges E The shortest distance between each side of the middle; Step S25: Find the minimum value of all elements in the objective function matrix Matrix. f min , minimum value f min Corresponding edge E min join in Gs , will the side E min Corresponding non S Add node S middle; Step S26: Establish the edge set of the newly added pipe segment E new ,Will E min Add the newly added pipe segment edge set E new ; Step S27, after each execution of steps S25-S26, the node set... S Add a node, node set V -S reduces the number of nodes by one. Gs Add one edge and one node accordingly. E new Add one edge accordingly; Step S28, continue to calculate the updated node set. V - S Each node set in the edge E min The distance is calculated and updated to the objective function matrix Matrix; Step S29, if S = V If the result is positive, the calculation process ends; otherwise, return to step S25. Step S210, the final result Gs for G 2, G 2 encompasses all nodes and is the connectivity diagram with the shortest total pipeline length between well sites.

2. The method for optimizing the topology of the gathering and transportation pipeline network in old oilfield areas according to claim 1, characterized in that, The operational energy consumption related parameters are for each well site. k The sum of flow distances to the transfer station, where the sum of flow distances is the well site. k fluid flow rate Q k Distance from fluid path L k The product of, expressed as F k = Q k × L k ,in L k Indicates well site k The fluid path distance from the fluid to the transfer station. Q k Indicates well site k Traffic, F k The larger the value, the higher the energy consumption; step S3 specifically involves: Step S31, corresponding to the connected graph G 1. Calculate the wells for each well site k Fluid path distance to the transfer station L1 k and well site k exist G Flow in 1 Q 1 k ;but G 1. Wells at each well site k corresponding F 1 k = Q 1 k × L 1 k ; Step S32, corresponding to the connected graph G 2. Calculate the wells for each well site. k Fluid path distance to the transfer station L 2 k and well site k exist G Flow in 2 Q 2 k ;but G 2 well sites k corresponding F 2 k = Q 2 k × L 2 k ; Step S33, Compare G 2 and G In 1, F 2 k and F 1 k The size, denoted by Δ F k = F 2 k – F 1 k ; Set and change the threshold Δ F critical If Δ F k <Δ F critical Then keep E new Zhongyu Well Site k The newly added pipe segment connected; if Δ F k ≥Δ F critical , then delete E new Zhongyu Well Site k The newly added pipe sections are connected.

3. The method for optimizing the topology of the gathering and transportation pipeline network in old oilfield areas according to claim 2, characterized in that, The calculation process for annual operating costs C1 and C2 in step S5 is as follows: Step S51, calculate the pipe segment j The annual operating cost is C j Operating costs C j Including the cost of heat loss due to heat dissipation in pipelines. S R,j and power loss due to friction loss S P,j ; Heat loss fee S R,j Specifically: ； in T S,j - Pipe section j The starting temperature, T E,j - Pipe section j The final temperature, Q j For pipe section j Traffic, ρ j - Pipe section j Fluid density, kg / m³ 3 ; C y - Pipe section j Specific heat capacity of oil at average oil temperature, kJ / (kg) ℃); e y - Fuel oil price, yuan / ton; B H - Calorific value of fuel oil, kJ / kg; η R - Heating furnace efficiency; Power loss cost S P,j Specifically: ； in, H j - Pipe section j The pressure drop, m; e d - Electricity price, yuan / (kW·h); η pe - Pump unit efficiency; Step S52: Calculate the pipe segment j Annual operating costs C j : C j =S R,j +S P,j The annual operating cost of the entire pipeline network is the sum of the annual operating costs of all pipeline segments, denoted as . C = ; Step S53, calculate according to step S52. G 1 corresponds to annual operating costs C 1 and G 3 k Corresponding annual operating costs C 2.

4. The method for optimizing the topology of the gathering and transportation pipeline network in old oilfield areas according to claim 3, characterized in that, The flow rate of pipe segment j Q j The calculation steps are as follows: Step S511, record Q k,j for well site k The fluid flows through the pipe section j The flow rate; if the well site k The fluid flows through the pipe section j ,but Q k,j = q k , q k Corresponding well site k The flow rate; if the well site k The fluid does not flow through the pipe section j ,but Q k,j =0; Step S512, then the pipe section j Traffic Q j for: .

5. The method for optimizing the topology of the gathering and transportation pipeline network in old oilfield areas according to claim 1, characterized in that, Step S6 specifically involves: Step S61, consider G 3 k Calculate the construction cost of the newly added pipeline section. G 3 k The equivalent annual cost of the entire pipeline network AC Equal annual fees AC The expression is: ； in: I This refers to all investments made in a year, including fixed asset investment and working capital. C Annual operating costs C2 ; S V To calculate the residual value of fixed assets recovered at the end of the period; W To calculate the working capital recovered at the end of the period; N For the calculation period; i The benchmark rate of return for the oil industry during financial evaluation i C ; It is the present value factor for a single payment, or the discount factor or present value factor; This is the coefficient for equal capital recovery; Step S62, Compare C 1 and AC ,if AC < C If 1 is selected, the corresponding new pipeline section will be constructed; otherwise, it will not be constructed.

6. The method for optimizing the topology of the gathering and transportation pipeline network in old oilfield areas according to claim 5, characterized in that, The total investment in the year I is G 3 k The cost of constructing new pipeline sections is as follows: ;in, For connected components G 3 k The total length of the newly built pipeline section B Cost per meter of pipe.

7. The method for optimizing the topology of the gathering and transportation pipeline network in old oilfield areas according to claim 6, characterized in that, Assumption G 3 k If the newly added pipelines are completed and put into operation in the current year, without considering the working capital recovered at the end of the calculation period and the residual value of fixed assets, then the corresponding... G 3 k Equal annual fees AC It can be simplified to: 。

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