Method and system for optimizing gathering and transportation system of high-water-content oil field

Abstract

The invention discloses a method and a system for optimizing a gathering and transportation system of a high-water-content oil field. The method comprises the following steps: acquiring original basic data of a gathering and transportation system to be optimized; according to the original basic parameters, an optimization model is used for optimizing the topology of the original gathering and transportation system, station yard and pipeline optimization layout information containing different configuration modes is output, the optimization model is a target function which uses different configuration mode technologies to constrain and consider the cost after coupling of the water injection system and the gathering and transportation system to be evaluated, and the optimization model is a target function which is used for optimizing the cost after coupling of the water injection system and the gathering and transportation system to be evaluated. The different configuration type processes comprise setting of pipeline relocation, station yard station withdrawal and water pre-diversion processes.

Description

Technical Field

[0001] This invention relates to the field of oilfield gathering and transportation system layout optimization technology, and in particular to a method and system for optimizing a gathering and transportation system in a high water-cut oilfield. Background Technology

[0002] As oilfields enter the mid-to-late stages of development, rising water cut leads to increasingly common issues with surface systems being oversized, resulting in high energy consumption and poor economic efficiency. Optimizing and simplifying surface systems in older oilfields has become a crucial means to improve their economic efficiency. Currently, the formulation of optimization and simplification plans for surface systems in older oilfield areas is primarily based on experience. Dagang Oilfield, considering the impact of various factors such as well production, water cut, crude oil pour point, and viscosity on the viscosity of crude oil emulsions, combined with the results of single-pipe oil gathering tests and experience from other oilfields, ultimately adopted a T-connection method to relocate the oil well gathering pipelines to the original metering station's external transmission pipelines. This eliminated the metering station and reduced the number of transfer stations, simplifying the gathering and transportation process. Honggang Oilfield, based on the principles of reducing land acquisition, facilitating management, and reducing the number of main and branch oil gathering lines, "thinned out" the metering station and transfer stations, and transformed the star-shaped pipeline network into a combination of star and branch-shaped structures. The Daqing Chaoyangou Oilfield has solved problems such as unbalanced system load, unreasonable layout, high energy consumption, and corrosion and aging of facilities by merging inefficient metering stations and oil transfer stations and eliminating the water supply process of the large oil transfer station.

[0003] Retrofitting schemes based on production experience often focus on optimizing a single aspect of the gathering and transportation system, such as pipeline connection methods or station load rates. Due to the high coupling nature of gathering and transportation systems, changing pipelines or removing stations can alter the hydrothermal dynamics of the pipelines, thus affecting the energy consumption of the entire system. Such methods require multiple trial calculations to satisfy all constraints and cannot easily yield the optimal solution. Furthermore, with the increasing application of optimization algorithms across various industries, the use of mathematical optimization to retrofit old oilfield gathering and transportation systems has gradually developed. Existing technologies consider constraints such as construction, operation, and maintenance costs, physical properties, and geographical information of the pipeline network system, and use simulated annealing algorithms to search for solutions to obtain the routing and specification design of the pipeline network system.

[0004] The existing technologies mentioned above, whether metaheuristic algorithms or mathematical programming algorithms, do not consider all constraints, thus failing to implement most of the measures involved in actual engineering transformation. Moreover, metaheuristic algorithms cannot guarantee the optimality of the solution, and their solution results are unstable.

[0005] Since older oilfields often have high water content, it is necessary to add a pre-water separation device at the oil transfer station to separate some of the free water in the produced fluid, thereby reducing system energy consumption. However, there is currently no existing technology that takes the setting of the pre-water separation device into account in the optimization model. Summary of the Invention

[0006] The purpose of this invention is to provide an optimization scheme for the gathering and transportation system of old oilfields that takes into account multiple constraints such as pre-water separation settings.

[0007] To address the aforementioned technical problems, this invention provides a method for optimizing a high water-cut oilfield gathering and transportation system, comprising: obtaining the original basic data of the gathering and transportation system to be optimized; optimizing the topology of the original gathering and transportation system using an optimization model based on the original basic parameters, and outputting station and pipeline optimization layout information containing different configurations, wherein the optimization model is an objective function constrained by different configuration processes to consider the cost of coupling the water injection system and the gathering and transportation system to be evaluated, and the different configuration processes include pipeline rerouting, station removal, and pre-water separation processes.

[0008] Preferably, the original basic data includes pipeline topology, oil well production parameters, oilfield physical property parameters, cost parameters of station nodes and pipelines, station process parameters, and pipeline design parameters.

[0009] Preferably, the objective function is a function that aims to minimize the sum of reconstruction investment and operating costs, wherein the objective function is expressed by the following expression:

[0010]

[0011] Where C represents the sum of investment and operating costs of the gathering and transmission pipeline layout scheme to be evaluated, I represents the depreciation factor, and CO j CI represents the operating cost of the j-th station. j C represents the cost of renovating the j-th station. pipe N represents the total cost of constructing new pipelines. S This represents the set of all stations in the gathering and transportation pipeline layout scheme to be evaluated.

[0012] Preferably, the optimization model further includes: a configuration-based process constraint group affecting the operating costs, station renovation costs, and new pipeline costs of each station in the original gathering and transportation system topology. The configuration-based process constraint group includes: pipeline connection constraints for deciding the pipeline renovation requirements between adjacent stations in the original gathering and transportation system topology; station removal constraints for deciding to implement station removal operations by analyzing the influence relationship between station removal and other variables; and pre-water distribution process constraints for deciding the pre-water distribution process settings by analyzing that the setting of water distribution stations in the gathering and transportation system should ensure that the water injection volume of the water injection system is in a balanced state.

[0013] Preferably, the pipeline connection constraint is used to represent the evaluation result of whether the pipeline between adjacent stations is a newly built pipeline or an existing pipeline, wherein the pipeline connection constraint is represented by the following expression:

[0014] Bpm，n +Rp m，n =Tp m，n

[0015] Among them, Bp m，n Rp represents a binary variable indicating whether a new pipeline is being constructed between station m and station n. m，n Tp is a binary variable representing the decision of whether the pipeline between station m and station n should be retained. m，n This represents a binary variable indicating whether a pipeline exists between station m and station n after the renovation.

[0016] Preferably, the station removal constraint is as follows: if the station node is not cancelled, the load rate of at least one inlet pipeline connected to the station is greater than the minimum allowable load rate and less than the maximum allowable load rate; or if the station node is cancelled, the station does not have an inlet pipeline and does not have a pressurization and recirculation process, a pre-separation water process, or an oil, gas and water treatment process.

[0017] Preferably, the pre-water separation process is constrained as follows: a station with a pre-water separation process should have a water injection pipeline connected to the water injection well or water injection station in the water injection system, and the water injection balance of the water injection system should be maintained; a station without a pre-water separation process should not construct a new water injection pipeline connected to the water injection well in the water injection system.

[0018] Preferably, the optimization model further includes: a secondary constraint group for constraining the configured process constraint group, the secondary constraint group including: a flow constraint for constraining the station's receiving and processing capacity and pipeline flow balance; a station load rate constraint for constraining the station's oil load rate and water load rate; and a hydrothermal constraint for constraining the station's outlet pressure and outlet temperature.

[0019] Preferably, the step of optimizing the original gathering and transportation system topology using an optimization model based on the original basic parameters and outputting station and pipeline optimization layout information with different configurations includes: converting the objective function into a linear model and performing linear segmentation to obtain a linear programming model; using the configuration process constraint group and the secondary constraint group as constraint boundaries, employing a branch and bound algorithm to solve the linear programming model based on the original basic parameters to obtain the optimized gathering and transportation network layout scheme.

[0020] On the other hand, embodiments of the present invention also provide a system for optimizing a high water-cut oilfield gathering and transportation system, comprising: an input data generation module configured to obtain the original basic data of the gathering and transportation system to be optimized; and a pipeline network optimization module configured to optimize the topology of the original gathering and transportation system based on the original basic parameters using an optimization model, and output station and pipeline optimization layout information containing different configurations, wherein the optimization model is an objective function constrained by different configuration processes to consider the cost of coupling the water injection system and the gathering and transportation system to be evaluated, and the different configuration processes include pipeline rerouting, station removal, and pre-water separation processes.

[0021] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0022] This invention proposes a method and system for optimizing the gathering and transportation system of high water-cut oilfields. The method and system categorize optimization and modification measures into three types: "series" (pipeline connection), "removal" (station removal), and "division" (pre-water allocation). Pre-water allocation is used as the coupling point between the gathering and transportation system and the water injection system. A mixed-integer nonlinear programming (MINLP) model is established with the objective function of minimizing the sum of reconstruction investment and operating costs. Constraints such as hydraulic and thermal factors, flow balance, and load balance are considered to construct a mathematical optimization model. Finally, a genetic algorithm is used to solve the mathematical model, directly obtaining the optimized gathering and transportation network and node layout results. Thus, this invention further optimizes the "series, removal, and division" constraints based on the existing coupling relationship between the gathering and transportation system and the water injection system, thereby improving the overall operating efficiency of the gathering and transportation system and reducing production and operating costs.

[0023] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the description, claims, and drawings. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0025] Figure 1 This is a schematic diagram illustrating the steps of a method for optimizing a gathering and transportation system in a high water-cut oilfield, as described in an embodiment of this application.

[0026] Figure 2 This is a schematic diagram illustrating the implementation principle of a method for optimizing a high water-cut oilfield gathering and transportation system according to an embodiment of this application.

[0027] Figure 3This is a schematic diagram of the topology of the gathering and transportation system before optimization, which is an example of a method for optimizing a gathering and transportation system in a high water-cut oilfield according to an embodiment of this application.

[0028] Figure 4 This is a schematic diagram of the optimized gathering and transportation system topology, which is an example of a method for optimizing a gathering and transportation system in a high water-cut oilfield, according to an embodiment of this application.

[0029] Figure 5 This is a system module block diagram for optimizing the gathering and transportation system of high water-cut oilfields, as described in an embodiment of this application. Detailed Implementation

[0030] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that, as long as there is no conflict, the various embodiments and features in the various embodiments of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0031] Furthermore, the steps illustrated in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Also, although a logical order is shown in the flowcharts, in some cases the steps shown or described may be performed in a different order than that shown here.

[0032] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms “a” and “an” as used herein are also intended to include the plural. It should also be understood that the terms “comprising” and / or “including” as used herein specify the presence of the stated features, integers, steps, operations, units, and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components, and / or combinations thereof.

[0033] To address the significant increase in the overall water cut of produced fluids in the mid-to-late stages of oilfield development in my country, leading to problems such as unbalanced processing loads in oil and water treatment systems, low average load rates in gathering and transportation systems, and high energy consumption, it is necessary to classify and represent engineering practice modification measures as constraints in mathematical expression. This leads to the development of a method and system for optimizing the gathering and transportation system in high-water-cut oilfields. This method and system implements configuration-based process constraints through a mathematical optimization model. Gathering and transportation modification measures are categorized into three types: "series" (pipeline connection), "removal" (station removal), and "separation" (pre-separation of water). Hydrothermal calculations are coupled with consideration of constraints related to hydrothermal, flow balance, and load balance. A mixed-integer nonlinear programming (MINLP) model is established with the objective function of minimizing the sum of modification investment and operating costs. This model optimizes the coupling relationship between the existing gathering and transportation system and the water injection system through "series, removal, separation, and simplification," thereby improving the operating efficiency of the gathering and transportation system and reducing production and operating costs.

[0034] Example 1

[0035] Figure 1 This is a schematic diagram illustrating the steps of a method for optimizing a high water-cut oilfield gathering and transportation system according to an embodiment of this application. See below for reference. Figure 1 The specific steps of the method for optimizing the gathering and transportation system of high water-cut oilfields (also known as the "gathering and transportation system optimization method") described in the embodiments of the present invention will be explained.

[0036] Step S110: Obtain the original basic data of the gathering and transportation system to be optimized. In practical applications, the gathering and transportation system has various types of nodes (oil well nodes and station nodes), and adjacent nodes are connected by pipelines. Among them, station nodes include: metering station (metering room) nodes, oil transfer station nodes, combined station nodes, mixed transportation pump station nodes, and water distribution station stages (the water distribution station is an oil transfer station node equipped with a pre-water distribution device).

[0037] In this embodiment of the invention, the original basic data includes, but is not limited to: the original pipeline network topology, the oil well production parameters of each oil well in the gathering and transportation system, the oilfield physical property parameters of the area where the gathering and transportation system is located, the cost parameters of station nodes and pipelines, the station process parameters, and the pipeline network design parameters.

[0038] After collecting the original basic data of the collection and transportation system to be evaluated, proceed to step S120.

[0039] Step S120: Based on the original basic parameters collected in step S110, the original gathering and transportation system topology (to be optimized) is optimized using an optimization model, and station and pipeline optimization layout information with different configurations is output.

[0040] In this embodiment of the invention, the optimization model is a pre-constructed mathematical optimization model that uses different configuration processes to constrain the objective function of cost parameters considering the coupling of the water injection system and the gathering and transportation system to be evaluated. The different configuration processes include at least: pipeline rerouting, station closure, and the setting of pre-diversion processes.

[0041] Before implementing step S120, the embodiments of the present invention further include the step of constructing the above-described optimization model.

[0042] In this embodiment of the invention, the objective function is a function that aims to minimize the sum of reconstruction investment and operating costs.

[0043] The objective function is expressed by the following expression:

[0044]

[0045] Where C represents the sum of investment and operating costs of the gathering and transmission pipeline layout scheme to be evaluated, I represents the depreciation factor, and CO j CI represents the operating cost of the j-th station. j C represents the cost of renovating the j-th station. pipe N represents the total cost of constructing new pipelines. S This represents the set of all stations in the gathering and transportation pipeline layout scheme to be evaluated (a set of various stations such as oil transfer stations, water distribution stations, combined stations, and mixed-transport pumping stations), and j represents the sequence number of the station element in the set.

[0046] Specifically, the station's operating costs CO j Only electricity and fuel costs that significantly impact the optimization of the gathering and transportation system are considered. Electricity costs include: the electricity costs of the transfer pumps used to transfer produced fluid at the oil transfer station, mixed pumping station, and water distribution station, as well as the internal and external transfer pumps at the combined station; and the electricity costs of the booster pumps and water injection pumps in the water injection system. Fuel costs refer to the operating costs of the heating furnaces, including: the fuel costs of the heating furnaces used to ensure smooth collection and transportation of produced fluid at the metering station, oil transfer station, and water distribution station, and the fuel costs of the heating furnaces used to ensure the produced fluid reaches the processing temperature at the combined station. Station renovation costs (CI) are also considered. j This mainly includes the investment in the renovation of pre-water distribution devices, water treatment devices, and water injection pump devices used for pre-water distribution retrofits. The cost of new pipelines includes the cost of new gathering and transmission pipelines and the cost of new water injection pipeline sections.

[0047] The aforementioned optimization model includes not only a cost objective function relating to system investment and operating costs, but also a set of configurable process constraints. This set of configurable process constraints can influence the operating costs, station renovation costs, and new pipeline construction costs of each station in the original gathering and transportation system topology. This set of configurable process constraints includes multiple different configurable process constraints.

[0048] In this embodiment of the invention, the configurable process constraint group specifically includes: pipeline series connection constraint (“series” constraint), station removal constraint (“removal” constraint), and pre-separation process setting constraint (“separation” constraint).

[0049] In the first embodiment, the pipeline connection constraint is a constraint used to determine the pipeline reconstruction requirements between adjacent stations in the original gathering and transportation system topology.

[0050] The pipeline series constraint is used to evaluate whether the pipeline between adjacent stations is a newly built pipeline or an existing pipeline. The "series" constraint is mainly used to decide whether there is a pipeline connection between stations, and if so, whether the pipeline is a newly built pipeline or an existing pipeline, thereby realizing pipeline reconstruction, changing the liquid flow direction within the gathering and transportation system, and completing the merging of stations.

[0051] The pipe connection constraint is represented by the following expression:

[0052] Bp m，n +Rp m，n =Tp m，n (2)

[0053] Among them, Bp m，n The binary variable representing whether the pipeline between station m and station n is a newly constructed pipeline (where Bp is a new pipeline if it is) indicates the critical condition. m，n =1, otherwise Bp m，n =0), Rp m，n A binary variable representing whether the pipeline between station m and station n is retained (if retained, then Rp). m，n =1, otherwise Rp m，n =0), Tp m，n Tp represents a binary variable indicating whether a pipeline exists between station m and station n after the renovation (if it exists, then Tp). m，n =1, otherwise Tp m，n =0).

[0054] In the second embodiment, the station removal constraint is a constraint used to decide whether to carry out the station removal operation by analyzing the influence relationship between the station removal and other variables.

[0055] The "removal" constraint includes: the station removal operation of the station renovation measures, and the relationship constraints between the station and other variables after the station is removed. The station removal constraint is: if the station node is not removed, the load rate of at least one inlet pipeline connected to the station is greater than the minimum allowable load rate and less than the maximum allowable load rate; or, if the station node is removed, the station does not have an inlet pipeline and does not have a booster transfer process, a pre-separation water process, or an oil, gas and water treatment process.

[0056] In the third embodiment, the pre-separation process (setting) constraint is used to determine the setting of the pre-separation process by analyzing whether the setting of the water distribution station of the gathering and transportation system should ensure that the water injection volume of the water injection system is in a balanced state. The "separation" constraint is a co-optimization constraint between the gathering and transportation system and the water injection system, i.e., a coupling constraint.

[0057] The coupling between the water injection system and the gathering and transportation system to be optimized is achieved by injecting water from the injection wells in the water injection system to the distribution stations in the gathering and transportation system to be optimized.

[0058] The constraints of the pre-separation water technology are as follows: stations with pre-separation water technology should have a water injection pipeline connected to the water injection wells or water injection stations in the water injection system, and the water injection balance of the water injection wells or water injection station nodes in the water injection system should be maintained; stations without pre-separation water technology should not construct new water injection pipelines connected to the water injection wells in the water injection system.

[0059] In other words, stations with pre-separation water technology will construct a new water injection pipeline to the injection wells or stations in the water injection system; while stations without pre-separation water technology will not construct a new water injection pipeline. Therefore, the water volume balance constraints of the water injection system need to be considered during the construction of the new water injection pipeline.

[0060] In one embodiment, the pre-water separation process constraints can be represented by the following expression:

[0061]

[0062] Where, q a q represents the water injection volume or allocated water injection volume of the a-th water injection node in the water injection system (where, if the water injection node is a water injection station, then q a q represents the total water injection volume of the injection station; if the injection node is an injection well, then q a (This indicates the injection volume of the well); Q a，b Q1 represents the flow rate from node a to node b of the water injection system; b′，a This represents the flow rate from node b′ of the gathering and transportation system to node a of the water injection system. That is, if node b′ of the gathering and transportation system is a newly built pre-separation water device, a new pipeline needs to be built to transport the pre-separated water to a certain node of the water injection system; N represents the set of nodes in the water injection system and the gathering and transportation system. tra This represents the set of transfer station nodes in a gathering and transportation system.

[0063] Therefore, for stations that need to be newly equipped with pre-water distribution facilities, the station renovation costs need to be considered, including the renovation costs of pre-water distribution facilities, water injection facilities, and newly constructed water injection pipelines.

[0064] Furthermore, the optimization model described in this embodiment of the invention also includes a secondary constraint group. This secondary constraint group is used to constrain the aforementioned configuration-type process constraint group.

[0065] In one embodiment, the secondary constraint group includes: flow constraints, station load rate constraints, and hydrothermal constraints.

[0066] In the first embodiment, flow constraints are used to constrain the station's receiving and processing volume and the pipeline flow balance.

[0067] Flow constraints are mainly divided into station receiving and processing capacity constraints and pipeline flow balance constraints. Station receiving and processing capacity constraints are used to determine the amount of oil, water, liquid, and water distributed to each station, as well as the processing capacity of the combined station. These can be further subdivided into oil quantity calculation constraints, water quantity calculation constraints, pre-distribution water quantity calculation constraints, oil and water processing capacity calculation constraints for the modified combined station, and receiving capacity conservation constraints. Pipeline flow constraints are mainly used to calculate the oil and water transport capacity of each pipeline to ensure the flow balance of the gathering and transportation system network. These can be divided into pipeline flow calculation constraints and network node flow balance constraints.

[0068] In the second embodiment, the station load rate constraint is used to constrain the oil load rate and water load rate of the station.

[0069] The station load rate constraint is used to calculate the oil load rate and water load rate of each station, and to constrain the maximum and minimum allowable load rates of each station. In calculating the station load rate, to refine the station processes and balance the load rates among the various systems within the station, the load rates of the oil treatment system and the water treatment system need to be calculated separately. Oil load rate and water load rate are determined for each station. By designing load rate constraints (ensuring that the oil load rate is greater than the minimum allowable load rate and less than the maximum allowable load rate, and ensuring that the water load rate is greater than the minimum allowable load rate and less than the maximum allowable load rate), the load rates of the oil treatment system and water treatment system are balanced, and this also assists in the decision-making of the water separation process.

[0070] In the third embodiment, hydrothermal constraints are used to constrain the station's outbound pressure and temperature.

[0071] The appropriate outlet pressure and temperature for oil transfer stations or water distribution stations are calculated using hydrothermal constraints to ensure the safe and stable operation of the pipeline network. The pressure at each station and well node in the pipeline network of the gathering and transportation system must be higher than the minimum allowable pressure and lower than the maximum allowable pressure, remaining within a safe pressure range. Simultaneously, the temperature at each station and well node must be higher than the minimum allowable temperature and lower than the maximum allowable temperature, remaining within a safe temperature range.

[0072] In summary, as Figure 2As shown, this invention considers constraints such as oil transfer station constraints, pipeline connection constraints, station removal constraints, pre-water distribution process, pipeline flow rate, station load rate, and pipeline hydraulic calculation, and establishes a mixed integer nonlinear programming (MINLP) model with the objective function of minimizing the sum of construction investment and operating costs.

[0073] In the process of solving the optimization model, this embodiment of the invention first converts the objective function into a linear model and performs linear segmentation to obtain a linear programming model; then, using the configuration process constraint group and secondary constraint group as constraint boundaries, the branch and bound algorithm is used to solve the linear programming model based on the collected original basic parameters to obtain the optimized collection and transportation pipeline layout scheme.

[0074] After forming a mixed-integer nonlinear programming (MINLP) model with the objective function of minimizing the sum of reconstruction investment and operating costs, this embodiment of the invention applies a piecewise linearization method to transform the objective function into a mixed-integer linear programming (MILP) model, and uses a branch and bound algorithm to solve it, thus realizing the transformation measures such as pipeline rerouting and reducing the number of oil transfer stations.

[0075] Therefore, the station and pipeline optimization layout information obtained by the embodiments of the present invention not only includes information on pipeline rerouting, station removal, and pre-water distribution process settings, but also shows the optimized gathering and transportation pipeline network layout.

[0076] Example 2

[0077] The following example test is conducted using the gathering and transportation system of an old oilfield in China to illustrate the implementation process and effects of the gathering and transportation system optimization method described in Example 1.

[0078] The original topology of the gathering and transportation system, such as Figure 3 As shown in the figure. The gathering and transportation system includes 47 oil wells, 14 metering rooms, 6 oil transfer stations, and 2 combined stations, with an annual operating cost of RMB 89.64 million.

[0079] The above optimization model was programmed using Python, and the branch and bound method was used to solve it by calling the Gurobi solver. Through optimization, a new gathering and transportation system topology was obtained, such as... Figure 4As shown in Table 1, the optimized system reduces the number of oil transfer stations by 3, constructs 4 new pipelines, and installs pre-water separation devices at 2 oil transfer stations. The annual operating cost of the optimized stations is RMB 78.18 million. A comparison of the operating costs before and after optimization for each station is shown in Table 1. The total cost of the station renovation is RMB 48.28 million, of which RMB 32 million is for the new pre-water separation devices and RMB 16.28 million is for the new pipeline sections. Compared to before optimization, the annual operating cost of the optimized gathering and transportation system is reduced by RMB 11.46 million, resulting in a static investment payback period of 4.21 years.

[0080] Table 1 Comparison of operating costs before and after optimization of the gathering and transportation system

[0081]

[0082] Example 3

[0083] Based on the gathering and transportation system optimization methods of Embodiments 1 and 2 described above, this invention also provides a system for optimizing the gathering and transportation system of high water-cut oilfields (also referred to as a "gathering and transportation system optimization system"). This gathering and transportation system optimization system is used to implement the above-described gathering and transportation system optimization methods.

[0084] Figure 5 This is a system module block diagram for optimizing the gathering and transportation system of high water-cut oilfields, as described in an embodiment of this application. Figure 5 As shown, the collection and transportation system optimization system described in this embodiment of the invention includes: an input data generation module 51 and a pipeline network scheme optimization module 52.

[0085] Specifically, the input data generation module 51 is implemented as described in step S110 above, and is configured to obtain the original basic data of the gathering and transportation system to be optimized; the rock genesis analysis module 52 is implemented as described in step S120 above, and is configured to optimize the topology of the original gathering and transportation system using an optimization model based on the original basic parameters, and output station and pipeline optimization layout information containing different configurations.

[0086] In one embodiment, the optimization model uses different configuration processes to constrain an objective function that considers the cost of coupling the water injection system with the gathering and transportation system under evaluation. These different configuration processes include pipeline rerouting, station closure, and the implementation of pre-separation processes.

[0087] This invention discloses a method and system for optimizing the gathering and transportation system of high water-cut oilfields. The method and system categorize optimization and modification measures into three types: "series" (pipeline connection), "removal" (station removal), and "division" (pre-water allocation). Pre-water allocation is used as the coupling point between the gathering and transportation system and the water injection system. A mixed-integer nonlinear programming (MINLP) model is established with the objective function of minimizing the sum of reconstruction investment and operating costs. Constraints such as hydraulic and thermal factors, flow balance, and load balance are considered to construct a mathematical optimization model. Finally, a genetic algorithm is used to solve the mathematical model, directly obtaining the optimized gathering and transportation network and node layout results. Thus, this invention further optimizes the "series, removal, and division" constraints based on the existing coupling relationship between the gathering and transportation system and the water injection system, thereby improving the overall operating efficiency of the gathering and transportation system and reducing production and operating costs.

[0088] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

[0089] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0090] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0091] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0092] The phrase "an embodiment" or "an embodiment" used in this specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "an embodiment" appearing in various places throughout the specification does not necessarily refer to the same embodiment.

[0093] While the embodiments disclosed in this invention are as described above, the content is merely for the purpose of facilitating understanding of the invention and is not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and changes in form and detail of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection of this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A method for optimizing the gathering and transportation system of a high water-cut oilfield, characterized in that, include: Obtain the raw basic data of the collection and transportation system to be optimized; Based on the original basic parameters, the original gathering and transportation system topology is optimized using an optimization model, and the output includes station and pipeline optimization layout information with different configurations. The optimization model is an objective function that uses different configuration processes to constrain the cost of coupling the water injection system and the gathering and transportation system to be evaluated. The different configuration processes include pipeline rerouting, station removal, and pre-water distribution process settings.

2. The method according to claim 1, characterized in that, The original basic data includes pipeline topology, oil well production parameters, oilfield physical property parameters, cost parameters of station nodes and pipelines, station process parameters, and pipeline design parameters.

3. The method according to claim 1 or 2, characterized in that, The objective function is a function that aims to minimize the sum of reconstruction investment and operating costs, and is expressed by the following expression: Where C represents the sum of investment and operating costs of the gathering and transmission pipeline layout scheme to be evaluated, I represents the depreciation factor, and CO j CI represents the operating cost of the j-th station. j C represents the cost of renovating the j-th station. pipe N represents the total cost of constructing new pipelines. S This represents the set of all stations in the gathering and transportation pipeline layout scheme to be evaluated.

4. The method according to any one of claims 1 to 3, characterized in that, The optimization model also includes: a configuration-based process constraint group that affects the operating costs, station renovation costs, and new pipeline construction costs of each station in the original gathering and transportation system topology. The configuration-based process constraint group includes: Pipeline connection constraints used to determine pipeline reconstruction requirements between adjacent stations in the original gathering and transportation system topology; Station closure constraints are used to determine whether to implement station closure operations by analyzing the influence of station closure on other variables; and Pre-water separation process constraints are used to determine the pre-water separation process settings by analyzing the setting of water distribution stations in the gathering and transportation system to ensure that the water injection volume of the water injection system is in a balanced state.

5. The method according to claim 4, characterized in that, The pipeline connection constraint is used to indicate whether the pipeline between adjacent stations is a newly built pipeline or an existing pipeline, and the pipeline connection constraint is represented by the following expression: Bp m，n +Rp m，n =Tp m，n Among them, Bp m，n Rp represents a binary variable indicating whether a new pipeline is being constructed between station m and station n. m，n Tp is a binary variable representing the decision of whether the pipeline between station m and station n should be retained. m，n This represents a binary variable indicating whether a pipeline exists between station m and station n after the renovation.

6. The method according to claim 4 or 5, characterized in that, The station closure constraint is as follows: If the station node is not cancelled, the load rate of at least one inlet pipeline connected to the station is greater than the minimum allowable load rate and less than the maximum allowable load rate; or If the station node is cancelled, the station will not have an inlet pipeline and will not have a pressurization and transfer process, a pre-separation process, or an oil, gas and water treatment process.

7. The method according to any one of claims 4 to 6, characterized in that, The pre-water separation process is constrained as follows: Stations with pre-separation water technology should have a water injection pipeline connected to the water injection wells or water injection stations in the water injection system, and should take into account maintaining the water injection balance of the water injection system. For stations without pre-separation water technology, no new water injection pipelines should be constructed to connect with the water injection wells in the water injection system.

8. The method according to any one of claims 4 to 7, characterized in that, The optimization model further includes: a secondary constraint group for constraining the configuration-type process constraint group, the secondary constraint group including: Flow constraints are used to constrain the balance between the receiving and processing capacity of the station and the pipeline flow. Station load rate constraints are used to constrain the oil load rate and water load rate of the station; and Hydrothermal constraints are used to constrain the outgoing pressure and temperature of a station.

9. The method according to claim 8, characterized in that, The step of optimizing the original gathering and transportation system topology using an optimization model based on the original basic parameters, and outputting optimized layout information for stations and pipelines with different configurations, includes: The objective function is converted into a linear model and then subjected to linear piecewise processing to obtain a linear programming model. Using the configured process constraint group and the secondary constraint group as constraint boundaries, the branch and bound algorithm is used to solve the linear programming model based on the original basic parameters to obtain the optimized collection and transportation pipeline layout scheme.

10. A system for optimizing the gathering and transportation system of high water-cut oilfields, characterized in that, include: The input data generation module is configured to obtain the raw basic data of the collection and transportation system to be optimized. The pipeline network optimization module is configured to optimize the original gathering and transportation system topology based on the original basic parameters using an optimization model, and output station and pipeline optimization layout information with different configurations. The optimization model is an objective function that uses different configuration processes to constrain the cost of coupling the water injection system and the gathering and transportation system to be evaluated. The different configuration processes include pipeline rerouting, station removal, and pre-water distribution process settings.

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