An energy-saving optimization and control method based on offshore oilfield water injection tubing

Abstract

This invention discloses an energy-saving optimization and control method for water injection tubing in offshore oilfields, relating to the field of intelligent water injection control technology. The method includes: denoising the characterization signal of the entire flow channel's operating state to obtain a denoised characterization signal; based on the denoised characterization signal, generating dynamic characteristics of the fluid state and local energy consumption of the entire tubing flow channel through a water injection energy efficiency coupling model; and using operating state feedback to correct the water injection operating state online, obtaining an updated energy-saving control instruction set. This invention achieves dynamic updates to the energy-saving control instruction set by using operating state feedback to correct the water injection operating state online, ensuring that the water injection process continuously adapts to the actual operating conditions of the tubing, effectively improving the energy efficiency and operational stability of water injection in offshore oilfields.

Description

Technical Field

[0001] This invention relates to the field of intelligent water injection control technology, and in particular to an energy-saving optimization and control method based on offshore oilfield water injection tubing. Background Technology

[0002] As wellhead control equipment in oil and gas field development, wellheads are gradually integrating pressure, temperature, and flow injection functions to support remote monitoring and intelligent management of water injection wells. With the increasing demands for water injection efficiency and reliability in offshore oilfields, closed-loop control based on multi-source sensing has become an important direction for expanding the functions of wellheads. Due to its non-invasive nature and sensitivity to mechanical conditions, operational monitoring is being explored for use in evaluating the operation of tubing systems.

[0003] However, existing wellheads still lack the ability to collaboratively perceive the state of themselves and the downstream water injection tubing throughout the entire flow path. The control logic relies heavily on preset operating parameters and cannot dynamically correlate the local energy consumption and structural state of the throttle valve and water injection tubing, making it difficult to achieve unified optimization of energy saving and safe operation under complex water injection conditions. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides an energy-saving optimization and control method based on offshore oilfield water injection tubing to solve the problem of minimizing energy consumption and optimizing operational safety during the water injection process while ensuring the safe operation of the wellhead.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides an energy-saving optimization and control method based on offshore oilfield water injection tubing. The method includes: synchronously extracting operational status data of the throttle valve and wellhead in the entire water injection well tubing flow channel; performing response inversion based on the water injection tubing flow channel model and operational status data to obtain a characterization signal of the entire flow channel operational status; denoising the characterization signal of the entire flow channel operational status to obtain a denoised characterization signal of the entire flow channel operational status; generating dynamic characteristics of the fluid state and local energy consumption of the entire tubing flow channel through a water injection energy efficiency coupling model based on the denoised characterization signal of the entire flow channel; generating an energy-saving control instruction set by adopting a multi-objective collaborative optimization method with energy minimization as the objective and tubing operational status as a safety constraint, based on the dynamic characteristics and reservoir water injection requirements; dynamically adjusting the water injection pump speed, throttle valve opening, and stratified injection parameters according to the energy-saving control instruction set to generate the water injection operational status; and using operational status feedback to correct the water injection operational status online to obtain an updated energy-saving control instruction set.

[0007] As a preferred embodiment of the energy-saving optimization and control method based on offshore oilfield water injection tubing described in this invention, the operating status data of the throttle valve and the wellhead in the entire tubing flow channel of the water injection well are extracted synchronously throughout the time period to obtain multi-channel original operating status data. The flow channel status is fused from the original operating status data of multiple channels. With time delay compensation, the flow channel pressure gradient, velocity distribution and energy dissipation characteristics are inverted based on the data nodes available in the upstream and downstream, and a characterization signal of the entire flow channel operating status is generated.

[0008] As a preferred embodiment of the energy-saving optimization and control method based on offshore oilfield water injection tubing described in this invention, the operating status information refers to the status signal content generated by the throttle valve and the wellhead under the action of fluid, reflecting the operating status and energy dissipation, and combined with the water injection channel section between the throttle valve and the formation inlet obtained by inversion, characterized by a combination of pressure fluctuation characteristics and flow stability indicators.

[0009] As a preferred embodiment of the energy-saving optimization and control method based on offshore oilfield water injection tubing described in this invention, the specific steps for denoising the characterization signal of the entire flow channel operation state to obtain a denoised characterization signal of the entire flow channel operation state are as follows. The data filtering method is used to suppress interference components in the characterization signal of the entire flow channel operation state, and to obtain the initially separated state components; Based on the flow channel fluid state obtained by inversion from the throttle valve, the wellhead, and the water injection tubing, feature enhancement processing is performed on the state components to obtain a denoised full-flow channel operation state characterization signal of the full tubing flow channel fluid state information.

[0010] As a preferred embodiment of the energy-saving optimization and control method based on offshore oilfield water injection tubing described in this invention, the water injection energy efficiency coupling model is constructed as follows: A water injection energy efficiency coupling model is constructed based on the whole tubing operation status perception layer, structure and status alignment layer, status and energy consumption coupling layer, and status and structure association solidification layer. The whole tubing string operation status sensing layer synchronously extracts the operation status data of the throttle valve, production tree and water injection string in the whole tubing string flow channel of the water injection well to obtain the original status time series data; The structure and state alignment layer performs time delay compensation processing on the original state time series data to obtain a set of local state fragments. The state and energy consumption coupling layer analyzes the dynamic characteristics of pressure and flow in the set of local state segments to identify the operating state and extract energy dissipation, thereby obtaining the dynamic characteristic sequence of local energy consumption. The state-structure association solidification layer performs consistency screening on the state response characteristics corresponding to multiple operations under the same water injection conditions in the dynamic feature sequence, eliminates abnormal items with deviations, obtains the state-structure coupling relationship framework, and constructs the water injection energy efficiency coupling model.

[0011] As a preferred embodiment of the energy-saving optimization and control method based on offshore oilfield water injection tubing described in this invention, the dynamic characteristics of the fluid state and local energy consumption of the entire tubing channel are generated through a water injection energy efficiency coupling model based on the characterization signal of the denoised full-channel operation state. The specific steps are as follows. Based on the characterization signal of the denoised full-channel operation status, the operation status data of the throttle valve and the wellhead are processed by component separation to obtain characteristic state segments. Based on the characteristic state segments, the structure-fluid coupling analysis method is used to jointly analyze the pressure gradient, flow stability and energy dissipation characteristics of the water injection channel section between the throttle valve and the formation obtained by inversion, so as to obtain the dynamic characteristics characterizing the fluid state and local energy consumption of the entire tubing channel.

[0012] As a preferred embodiment of the energy-saving optimization and control method based on offshore oilfield water injection tubing described in this invention, the reservoir water injection demand refers to dynamic water injection based on the water injection pressure, injection volume, and interlayer water absorption capacity difference of the offshore oilfield reservoir.

[0013] As a preferred embodiment of the energy-saving optimization and control method based on offshore oilfield water injection tubing described in this invention, the method involves generating an energy-saving control instruction set by employing a multi-objective collaborative optimization method based on dynamic characteristics and reservoir water injection requirements, with energy consumption minimization as the objective and tubing operation status as a safety constraint. The specific steps are as follows: Based on the dynamic characteristics and reservoir water injection requirements, with the total energy consumption of water injection as the optimization objective, a multi-objective collaborative optimization method is adopted to jointly weigh the pressure drop of the throttle valve, the pressure fluctuation intensity of the wellhead, the flow velocity of the water injection channel section between the throttle valve and the water injection sand tubing obtained by inversion, and the pressure difference of the water injection tubing, to obtain a feasible combination of controllable parameters with the minimum total energy consumption, thus forming a feasible controllable parameter space. Based on the feasible controllable parameter space, the pump speed, throttle valve opening and stratified injection parameters are optimized in a coordinated manner to generate an energy-saving control instruction set.

[0014] As a preferred embodiment of the energy-saving optimization and control method based on offshore oilfield water injection tubing described in this invention, the specific steps for dynamically adjusting the water injection pump speed, throttle valve opening, and stratified injection parameters according to the energy-saving control instruction set to generate the water injection operation status are as follows. Based on the energy-saving control instruction set, the water injection pump speed, throttle valve opening and stratified injection parameters are synchronously adjusted to obtain the water injection execution parameters. The water injection execution parameters are dynamically executed and adapted to the flow regime to obtain a water injection operation state consistent with the energy-saving control instruction set.

[0015] As a preferred embodiment of the energy-saving optimization and control method based on offshore oilfield water injection tubing described in this invention, the specific steps for using operational status feedback to online correct the water injection operation status and obtain an updated energy-saving control instruction set are as follows. Based on the extracted throttle valve and tree operating status data, and combined with the flow channel model based on the water injection tubing, the characterization signal of the entire flow channel operating status is inverted to perform online deviation correction of the water injection operating status and obtain dynamic deviation information between the water injection operating status and the state response. Based on dynamic deviation information, the energy-saving control instruction set is fine-tuned online using operational status feedback to obtain an updated energy-saving control instruction set.

[0016] The beneficial effects of this invention are as follows: By constructing a water injection energy efficiency coupling model, dynamic characteristics of the operating status and local energy consumption of the throttle valve, the wellhead, and the water injection tubing are generated, providing input for multi-objective collaborative optimization, and enabling the control commands to take into account both energy consumption minimization and tubing safety constraints; by using operating status feedback to correct the water injection operating status online, the energy-saving control command set is dynamically updated, ensuring that the water injection process continuously adapts to the actual operating conditions of the tubing, and effectively improving the water injection energy efficiency and operational stability of offshore oilfields. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of an energy-saving optimization and control method based on offshore oilfield water injection tubing.

[0019] Figure 2 This is a flowchart of energy-saving control of water injection tubing based on state awareness.

[0020] Figure 3 The flowchart shows the construction and operation of the water injection energy efficiency coupling model.

[0021] Figure 4 This is a flowchart of closed-loop energy regulation and operational status feedback. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0025] Reference Figures 1-4 This is one embodiment of the present invention, which provides an energy-saving optimization and control method based on offshore oilfield water injection tubing, comprising the following steps: S1: Simultaneously extract the operating status data of the throttle valve and the wellhead in the entire tubing flow channel of the water injection well, and based on the water injection tubing and the flow channel model of the water injection tubing, combine the operating status data to perform response inversion and obtain the characterization signal of the entire flow channel operating status.

[0026] S1.1: Simultaneously extract the operating status data of the throttle valve and the wellhead in the entire tubing of the water injection well throughout the entire time frame to obtain multi-channel raw operating status data.

[0027] Furthermore, multiple data extraction channels are deployed at the outlet of the throttle valve, the tree body, and the outlet of the water injection tubing in the entire tubing flow path of the water injection well, forming a set of data channels covering the data nodes that can be acquired. The operating status data of each location is continuously extracted through the extraction cycle of the data extraction channels, and synchronous extraction is performed at all times to obtain multi-channel raw status response data of the operating status of the entire tubing flow path.

[0028] It should be noted that the data extraction channel refers to acquiring and reading the pressure, differential pressure, flow rate, and signals generated by the throttle valve, the wellhead, and the water injection tubing under the action of fluid.

[0029] The extraction cycle includes the number of times the running data is extracted per second.

[0030] Operational status data refers to the operational data generated by pressure fluctuations, flow rate changes, and mechanical factors in throttle valves, wellheads, and water injection tubing under the influence of fluids.

[0031] A data channel set refers to a collection of multiple data extraction channels that are laid out along the entire tubing of a water injection well and simultaneously acquire operational status data of the throttle valve, the wellhead, and the water injection tubing.

[0032] S1.2 performs flow channel state fusion on the original operating status data of multiple channels, adopts time delay compensation, and inverts the flow channel pressure gradient, velocity distribution and energy dissipation characteristics based on the data nodes available in the upstream and downstream, generating a characterization signal of the entire flow channel operating status.

[0033] Furthermore, based on the multi-channel raw state response data extracted from the operating status data of the throttle valve, production tree, and water injection tubing in the entire tubing flow channel of the water injection well, the flow channel state is fused by the multi-channel raw state response data. Based on the flow channel pressure gradient and velocity distribution inverted from the measurable node response, the spatial characteristics of the state response generated by the throttle valve, production tree, and water injection tubing under the action of fluid are fused to form a characterization signal of the entire flow channel operating status of the entire tubing flow channel.

[0034] Flow state fusion is based on the multi-channel raw state response data extracted from the data extraction channel array deployed along the entire flow channel of the injection well. It utilizes the spatial positional relationship between each data extraction channel and the propagation characteristics of fluid in the pipe. By taking into account the propagation delay of the operating data from the throttle valve, the Christmas tree, and the injection tubing to each data extraction channel, the state response of each channel is time-domain aligned based on the propagation delay and fused according to the data extraction channel position to obtain the energy dissipation and pressure drop distribution corresponding to each structural position. Furthermore, the fluid state distribution of the injection flow channel section between adjacent data extraction channels is inverted to form a continuous state field covering the entire flow channel, thus obtaining a characterization signal of the entire flow channel operating state that represents the operating state of the throttle valve, the Christmas tree, and the injection tubing.

[0035] The preferred method is to integrate the flow channel state based on the multi-channel raw state response data extracted from the data channel set, and to invert the continuous fluid state distribution of the entire flow channel from the throttle valve to the water injection tubing based on the measurable node response. The state of the water injection tubing section is generated by the inversion of the upstream and downstream data nodes, forming a characterization signal of the entire flow channel operating state that represents the operating state of the throttle valve, the wellhead, and the water injection tubing.

[0036] Specifically, spatial characteristics refer to the spatial distribution differences in the state responses of the throttle valve, the Christmas tree, and the water injection tubing within the entire tubing flow path of the water injection well, caused by their different positions.

[0037] S2: Denoise the characterization signal of the entire flow channel operation state to obtain a denoised characterization signal of the entire flow channel operation state.

[0038] S2.1: Operational status information refers to the status signals generated by the throttle valve and the wellhead under the action of fluid, reflecting the operational status and energy dissipation. It is combined with the water injection channel section between the throttle valve and the formation inlet obtained by inversion, and characterized by a combination of pressure fluctuation characteristics and flow stability indicators.

[0039] The data filtering method is used to suppress interference components in the characterization signal of the entire flow channel operation state, and to obtain the initially separated state components.

[0040] Furthermore, based on the operating status signals generated by the throttle valve, the wellhead, and the water injection tubing under the action of fluid, a data filtering method is used to suppress interference components in the characterization signals of the entire flow channel, retain the operating status information of the fluid state of the entire tubing flow channel, suppress environmental noise, pump body and non-structural interference components, and obtain the preliminary separated state components.

[0041] Specifically, the data filtering method refers to applying state filtering processing to the characterization signal of the entire flow channel's operating state, retaining the state components generated by the throttle valve, the wellhead, and the water injection string under the action of the fluid, while suppressing the interference components of the statistical filtering processing.

[0042] The characterization signal of the entire flow channel operation status is obtained by fusing and reconstructing the operation status data of the throttle valve, the wellhead, and the water injection tubing.

[0043] Interference components refer to the state components in the characterization signal of the entire flow channel operation state, excluding the hydraulic response content generated by the throttle valve, the wellhead, and the water injection string under the action of fluid. These include offshore platform transmission, water injection pump start-up and shutdown impact, cable electromagnetic interference, false signals caused by thermal expansion and contraction of the pipe wall, as well as data extraction channel drift and communication noise.

[0044] S2.2: Based on the flow channel fluid state obtained by inversion based on the throttle valve, production tree and water injection tubing, the state components are subjected to feature enhancement processing to obtain the characterization signal of the denoised full flow channel operation state of the full tubing flow channel fluid state information.

[0045] Furthermore, based on the fluid state of the entire tubing flow channel, a data filtering method is used to suppress interference components in the characterization signal of the entire flow channel operation state. Based on the characteristics of the fluid state of the entire tubing flow channel, feature enhancement processing is performed on the initially separated state components. The enhancement targets are the components of the operation state and energy dissipation of the throttle valve, the wellhead, and the water injection tubing under the action of fluid, highlighting the operation state information of the entire tubing flow channel fluid state, and obtaining a denoised characterization signal of the entire flow channel operation state that retains the fluid state of the entire tubing flow channel.

[0046] It should be noted that the characteristics of the fluid state in the entire tubing flow path originate from the state response of the throttle valve, the wellhead, and the water injection tubing under the action of the fluid.

[0047] The characteristics of the fluid state in the entire tubular flow channel are derived from the historical operating condition calibration library and the historical operating condition calibration library interval identified by the water injection energy efficiency coupling model in the previous control cycle. The historical calibration library is incrementally updated using a sliding time window.

[0048] The historical calibration database refers to a mapping database of structural characteristics and energy consumption operation characteristics obtained by offline extraction of the state response of throttle valves, wellheads, and water injection tubing under different operating conditions and their corresponding operating states (such as opening degree, flow velocity, and pressure difference) before commissioning and during historical water injection cycles.

[0049] Feature enhancement processing refers to strengthening the components that reflect the operating status and energy dissipation of the initially separated state components, such as the throttle valve, the wellhead, and the water injection string under the action of fluid (enhancing the intensity of the components in the characterization signal of the entire flow channel operating status by denoising).

[0050] Instantaneous fluctuation characteristics refer to the short-term changes in the state response signals of throttle valves, wellheads, and water injection tubing under the action of fluids, reflecting the dynamic disturbances and energy dissipation behavior of the operating state.

[0051] S3: Based on the characterization signal of the denoised full-channel operation status, the dynamic characteristics of the fluid state and local energy consumption of the entire tubular flow channel are generated through the water injection energy efficiency coupling model; the water injection energy efficiency coupling model is constructed based on the full-channel operation status perception layer, the structure and state alignment layer, the state and energy consumption coupling layer, and the state and structure association solidification layer.

[0052] S3.1: The whole tubing string operation status sensing layer synchronously extracts the operation status data of the throttle valve, production tree and water injection string in the whole tubing string flow channel of the water injection well to obtain the original status time series data.

[0053] Furthermore, based on the multi-channel original state response data, the spatial and temporal state responses at each location are integrated through flow channel state fusion to generate a characterization signal of the entire flow channel operation state covering the entire tubular flow channel. The reconstructed characterization signal of the entire flow channel operation state is then used as input to the water injection energy efficiency coupling model to obtain the original state time series data.

[0054] S3.2: Structure and state alignment layer, performs time delay compensation processing on the original state time series data to obtain a set of local state fragments.

[0055] Furthermore, based on the original state time series data, according to the positional distribution of the throttle valve, the wellhead, and the water injection tubing in the entire tubing flow channel, the propagation delay of the state signal at each data extraction channel location is calculated, and time delay compensation processing is used to time-align the original state time series data to generate a set of local state fragments corresponding to each structural unit.

[0056] Specifically, time delay compensation processing refers to aligning the original state time series data according to the differences in the propagation path and flow velocity of the fluid at different locations in the full tubing of the injection well, thereby eliminating the state response time offset caused by the different locations of the data extraction channels.

[0057] S3.3: State and energy consumption coupling layer. By analyzing the dynamic characteristics of pressure and flow in the set of local state segments, the operating state is identified and energy dissipation is extracted to obtain the dynamic characteristic sequence of local energy consumption.

[0058] Furthermore, based on the pressure fluctuation amplitude, flow stability index, and differential pressure evolution trend in the local state fragment set, the hydraulic operation status of the throttle valve, production tree, and water injection string under fluid action is identified, and the flow resistance dissipation characteristics are obtained simultaneously. Combined with the energy dissipation characteristics of the water injection channel section between the throttle valve and the water injection string obtained by inversion, a local energy consumption dynamic characteristic sequence reflecting the energy consumption evolution behavior of the entire string (including the water injection string section) is formed.

[0059] It should be noted that the identification of hydraulic operating status refers to characterizing the pressure drop characteristics, flow response delay, and flow stability of the throttle valve, production tree, and water injection string under fluid excitation based on local state segments.

[0060] Flow resistance dissipation characteristics refer to the energy loss in the operating status signal caused by local geometric changes, frictional resistance and turbulent disturbances when the fluid flows through the throttle valve, the wellhead and the water injection string.

[0061] S3.4: State and structure association solidification layer. Consistency screening is performed on the state response characteristics corresponding to multiple runs under the same water injection conditions in the dynamic feature sequence. Anomalies with deviations are eliminated to obtain the state and structure coupling relationship framework and construct the water injection energy efficiency coupling model.

[0062] Furthermore, based on the dynamic characteristic sequence of local energy consumption, and according to the consistency between the state response and the operating state of the throttle valve, the wellhead, and the water injection tubing, the dynamic characteristic sequence is screened to obtain a framework of state-structure coupling relationship, and a water injection energy efficiency coupling model is constructed.

[0063] It should be noted that consistency screening refers to retaining the characteristics of synchronous changes in the water injection string and state in the dynamic characteristic sequence of local energy consumption based on the correlation between the operating state and state response of the throttle valve, the wellhead, and the water injection string under the action of fluid, and removing abnormal characteristics that do not match the structural operating state and deviate from normal coupling (removing abnormal items where the inverted flow channel state is inconsistent with the response of the upstream and downstream available data nodes), thus obtaining the framework of the coupling relationship between state and structure.

[0064] The training process of the water injection energy efficiency coupling model is as follows: the original state time series data is obtained by using the whole tubing operation perception layer, and then the time delay compensation is performed by the structure and state alignment layer to form a set of local state fragments corresponding to each location. The state and energy consumption coupling layer extracts the dynamic feature sequence reflecting the operation state and energy dissipation. In the state and structure association solidification layer, based on the consistency of hydraulic characteristics and actual energy consumption under historical operating conditions, stable and reproducible operation and structure mapping relationships (covering throttle valves, production trees, water injection tubing and water injection channel sections) are selected to form a real-time simulation framework of state and structure coupling relationships.

[0065] S3.5: Based on the characterization signal of the denoised full-channel operation status, the operation status data of the throttle valve and the wellhead are processed by component separation to obtain characteristic state segments.

[0066] Furthermore, the characterization signal of the denoised full-channel operation state is spatiotemporally segmented according to the structural position of the state response of the throttle valve, the Christmas tree, and the water injection tubing. The state response components generated by each structure under the action of fluid are separated. Based on the structural position of each structure's state response in the spatiotemporal segmentation according to the structural position, the separated state response components are processed by component separation (inversion of the fluid state of the water injection channel section) to obtain the characteristic state segments of the throttle valve, the Christmas tree, and the water injection tubing.

[0067] Specifically, component separation processing refers to separating the state components belonging to the throttle valve, the wellhead, and the water injection string in the mixed state response by dividing the structural state response into independent characteristic state segments at the structural location that is spatiotemporally segmented according to the structural location.

[0068] S3.6 Based on the characteristic state segments, the structure-fluid coupling analysis method is used to jointly analyze the pressure gradient, flow stability and energy dissipation characteristics of the water injection channel section between the throttle valve and the formation obtained by inversion, so as to obtain the dynamic characteristics characterizing the fluid state and local energy consumption of the entire tubing channel.

[0069] Furthermore, the characteristic state segments are input into the state and energy consumption coupling layer of the water injection energy efficiency coupling model. By analyzing the pressure gradient, flow stability and local pressure difference of the characteristic state segments, the operating states of the throttle valve, the wellhead and the water injection tubing are identified. At the same time, the energy dissipation information associated with each structural location is extracted. The structure and fluid coupling analysis method is used to jointly analyze the operating state and energy dissipation of the water injection channel section between the throttle valve and the water injection tubing obtained by inversion, and generate the dynamic characteristics of the fluid state and local energy consumption of the entire tubing channel.

[0070] The dynamic characteristics of local energy consumption are generated by the following expression: ; in, It is a state indicator of the fluid state and local energy consumption of the entire tubular flow channel. It is the first The local energy dissipation characterization quantity corresponding to each monitored structure (i.e., throttle valve, wellhead, and water injection tubing). The four monitored structures in the entire injection well tubing flow channel are numbered as follows: throttle valve, Christmas tree, injection tubing flow channel section, and injection tubing.

[0071] It should be noted that each Based on the same extraction and processing procedures, and having the same units of measurement, they are directly summed to form the comprehensive energy consumption status index. The preprocessed feature representations used for coupled analysis, rather than the original physical quantities, have consistent dimensions in the formulas for generating the dynamic features of local energy consumption.

[0072] It should be noted that the structure-fluid coupling analysis method refers to a method based on the operational response generated by the interaction between the water injection tubing structure and the internal fluid. By analyzing the state characteristics of the throttle valve, the wellhead, and the water injection tubing during fluid generation, the structural mechanical response is coupled with the fluid dynamics behavior, and the structural operating state is simultaneously identified and local energy dissipation is quantified.

[0073] A superior structural-fluid coupling analysis method utilizes the pressure fluctuation amplitude and flow stability index in the operating state signal to reflect the energy loss and structural state caused by throttling and friction factors when the fluid passes through different tubing components. The analysis process relies on the state and energy consumption coupling layer in the water injection energy efficiency coupling model and performs joint analysis based on the extracted characteristic state segments and tubing structure.

[0074] S4: Based on dynamic characteristics and reservoir water injection requirements, a multi-objective collaborative optimization method is adopted with the goal of minimizing energy consumption and the safety constraint of tubing operation status to generate an energy-saving control instruction set.

[0075] S4.1: The reservoir water injection demand refers to dynamic water injection based on the water injection pressure, injection volume, and interlayer water absorption capacity difference of the offshore oilfield reservoir.

[0076] Based on dynamic characteristics and reservoir water injection requirements, with total water injection energy consumption as the optimization objective, a multi-objective collaborative optimization method is adopted to jointly weigh the pressure drop of the throttle valve, the pressure fluctuation intensity of the wellhead, the flow velocity of the water injection channel section between the throttle valve and the water injection tubing obtained by inversion, and the pressure difference of the water injection tubing, to obtain the feasible combination of controllable parameters with the minimum total energy consumption, thus forming a feasible controllable parameter space.

[0077] Furthermore, based on the dynamic characteristics of the fluid state and local energy consumption of the entire tubing flow channel, and combined with the water injection pressure, injection volume, and interlayer water absorption capacity differences in reservoir water injection demand, the water injection pump speed, throttle valve opening, and stratified injection parameters are used as adjustable control variables. Under the safe operating conditions of the throttle valve, the wellhead, the water injection flow channel section between the inverted throttle valve and the water injection tubing, a multi-objective collaborative optimization method is used to simultaneously consider reducing energy consumption and meeting operational safety requirements. This allows for the selection of combinations of water injection pump speed, throttle valve opening, and stratified injection parameters that meet both safety constraints and low energy consumption, thus forming a feasible controllable parameter space.

[0078] Specifically, the multi-objective collaborative optimization method refers to, during the operation of the entire injection well tubing, taking as a premise the safety constraints the pressure drop of the throttle valve, the intensity of pressure fluctuations in the wellhead, and the inverted flow velocity and pressure difference parameters of the injection tubing section between the throttle valve and the injection tubing, simultaneously minimizing total injection energy consumption, meeting reservoir injection demand (including injection pressure, injection volume, and the balance of interlayer water absorption capacity), and the stability of the injection tubing as multiple coupled optimization objectives. Through the mapping relationship between adjustable control variables (including injection pump speed, throttle valve opening, and stratified injection parameters) and objectives and constraints, multi-objective optimization is used to select a set of engineering-acceptable control parameter combinations within the feasible solution space, achieving synergy between energy efficiency and operational safety, and ensuring that the injection operation is dynamically executed in a highly efficient, stable, and reliable state.

[0079] The adjustable control variables refer to the water injection pump speed, throttle valve opening, and stratified injection parameters.

[0080] Water injection pressure refers to the pressure that must be maintained when water is injected into a water injection well to meet the reservoir's oil displacement requirements.

[0081] The injection volume refers to the amount of water allocated to a single well and a single layer based on oilfield development.

[0082] Poor interlayer water absorption capacity refers to the difference in water absorption capacity between different oil layers in a reservoir under the same water injection conditions.

[0083] The safety requirement refers to the safe operation of the throttle valve, the wellhead, the water injection channel section between the throttle valve and the water injection tubing obtained from the inversion, and the water injection tubing. The safety status of the water injection channel section between the throttle valve and the water injection tubing obtained from the inversion is determined based on the flow velocity, pressure gradient, and energy dissipation characteristics. The operating status refers to the normal operation of the structural bearing capacity, fluid flow, and sand control function, and the absence of structural damage, flow instability, and sand control failure during the water injection process.

[0084] S4.2: Based on the feasible controllable parameter space, the pump speed, throttle valve opening and stratified injection parameters are optimized in a coordinated manner to generate an energy-saving control instruction set.

[0085] Furthermore, within the feasible controllable parameter space, combining the dynamic characteristics of the fluid state and local energy consumption of the entire tubing flow channel with the reservoir water injection requirements, a multi-objective collaborative optimization method is used to collaboratively optimize the water injection pump speed, throttle valve opening, and stratified injection parameters. Under the constraints of the throttle valve, the wellhead, the water injection flow channel section between the throttle valve and the water injection tubing obtained from the inversion, and the safe operation of the water injection tubing, the overall energy consumption is minimized, and the water injection pump speed, throttle valve opening, and stratified injection parameters for controlling the water injection operation are output, forming an energy-saving control instruction set.

[0086] It should be noted that collaborative optimization refers to the process in which, in a multi-objective collaborative optimization method, the coupling relationship between the injection pump speed, throttle valve opening, and stratified injection parameters is considered, and synchronous adjustments are made under the safety constraints of the tubing operation state to achieve the optimization between minimizing energy consumption and reservoir water injection demand.

[0087] The energy-saving control instruction set includes instructions for water injection pump speed, throttle valve opening degree, and tiered injection parameter instructions.

[0088] The water pump speed command is in rpm, with an allowable range of 500–2800 rpm and a minimum adjustment step of 10 rpm.

[0089] Throttling valve opening command, in percentage, ranging from 10% to 100% (to avoid water hammer caused by complete closure), with an adjustment step of 1%.

[0090] The layered injection parameter command indicates the injection flow rate of each layer, in m³ / d. The sum of these parameters equals the total injection volume. The minimum injection volume for a single layer is not less than 5 m³ / d to maintain the sand control screen tube.

[0091] S5: Based on the energy-saving control instruction set, dynamically adjust the water injection pump speed, throttle valve opening, and stratified injection parameters to generate the water injection operation status.

[0092] S5.1: Based on the energy-saving control instruction set, the water injection pump speed, throttle valve opening, and tiered injection parameters are synchronously adjusted to obtain the water injection execution parameters.

[0093] Furthermore, the energy-saving control command set maps the water injection pump speed command, throttle valve opening command, and tiered injection parameter command to the control interface. Multi-channel synchronous output is used to synchronize the control signals output within the same control cycle. The water injection pump speed command drives the water injection pump to adjust its operating speed, the throttle valve opening command drives the throttle valve to adjust its flow cross section, and the tiered injection parameter command drives the tiered injection to adjust the distribution ratio of each water injection layer. The control signals are synchronously adjusted and processed in time sequence, so that the water injection pump speed, throttle valve opening, and tiered injection parameters are coordinated and consistent in their control actions, and consistent water injection execution parameters are obtained from the energy-saving control command set.

[0094] Specifically, synchronous regulation refers to adjusting the water injection pump, throttle valve, and stratified injection in a time-aligned manner according to the energy-saving regulation instruction set within the same regulation cycle, so that the operating status changes synchronously at the same time according to their respective instructions.

[0095] Water injection execution parameters refer to the set of control parameters that drive the operation of the water injection pump, throttle valve, and tiered injection parameters by synchronously adjusting the water injection pump speed, throttle valve opening, and tiered injection parameters according to the energy-saving control instruction set.

[0096] S5.2: Dynamically execute and adapt the water injection parameters to the flow regime to obtain a water injection operation state consistent with the energy-saving control instruction set.

[0097] Furthermore, based on the water injection execution parameters, combined with the operating status data of the throttle valve, the wellhead, the water injection channel section between the throttle valve and the formation obtained by inversion, and the water injection tubing, the dynamic characteristics of the fluid state and local energy consumption of the entire tubing channel are generated through the water injection energy efficiency coupling model. Based on the dynamic characteristics, the water injection execution parameters are dynamically executed and adapted to the flow state, so that the flow state of the fluid in the entire tubing channel during the water injection process simultaneously meets the energy consumption minimization target of the energy-saving control instruction set and the safety constraints of the tubing operating state, thus obtaining the water injection operating state consistent with the energy-saving control instruction set.

[0098] It should be noted that dynamic execution and flow regime adaptation refers to the process of tracking flow regime changes during water injection, adjusting pump speed, valve opening, and stratified injection execution volume online, and adapting the operation to the water injection state and energy-saving control commands.

[0099] S6: Utilize operational status feedback to correct the water injection operation status online and obtain an updated set of energy-saving control instructions.

[0100] S6.1: Based on the extracted operating status data of the throttle valve, the wellhead, and the water injection tubing, and combined with the characterization signal of the entire flow channel operating status obtained by inverting the operating status data of the throttle valve and the wellhead, the deviation of the water injection operating status is corrected online to obtain the dynamic deviation information between the water injection operating status and the state response.

[0101] Furthermore, the operating status signal of the water injection flow channel section between the throttle valve and the water injection pipe column, obtained by the inversion of the entire pipe column flow channel, is input into the water injection energy efficiency coupling model. Time delay compensation is performed through the structure and state alignment layer to obtain a set of local state segments. The pressure fluctuation amplitude and flow stability index in the set of local state segments are analyzed by the state and energy consumption coupling layer to extract the dynamic characteristics of the fluid state and local energy consumption of the entire pipe column flow channel. The dynamic characteristics are compared and corrected online with the water injection operating status and dynamic characteristics of the energy-saving control command set. The difference between the operating status and dynamic characteristics in the state response is identified through the operating status feedback to obtain the dynamic deviation information between the water injection operating status and the state response.

[0102] It should be noted that online calibration refers to dynamically generating operational deviation information based on the difference in the state response of the water injection operation state by comparing the characterization signal of the entire flow channel of the whole tubing. This is done in order to adjust the energy-saving control command set.

[0103] Operational status feedback refers to the process of correcting deviations in the water injection operation status online based on the characterization signals of the entire flow channel of the entire tubing, and using the deviation information to fine-tune the energy-saving control command set online.

[0104] S6.2 Based on the dynamic deviation information, the energy-saving control instruction set is fine-tuned online using the operating status feedback to obtain an updated energy-saving control instruction set.

[0105] Furthermore, by adopting operational status feedback, dynamic deviation information is used as feedback input. With energy consumption minimization and tubing operation status as safety constraints, the control commands for water injection pump speed, throttle valve opening, and stratified injection parameters are fine-tuned online and corrected in real time, generating an updated energy-saving control command set that is consistent with the current operational feedback and meets the reservoir water injection requirements.

[0106] The updated energy-saving control instruction set is generated using the following expression: ; in, It is the updated regulatory output indicator. It is the first The target quantity for this project is determined by the reservoir water injection demand. It is the first The operational status feedback correction amount of the item is obtained from the dynamic deviation information and represents the correction range that needs to be adjusted (normalized, dimensionless). It is the first Feedback adjustment indicators for items, It is the target setting quantity. It is the operation status feedback correction amount. It is a feedback adjustment indicator. These are the sequence numbers of the three energy-saving control commands: water injection pump speed, throttle valve opening, and stratified injection parameters.

[0107] It should be noted that the control characteristic quantity is transformed into a dimensionless control characteristic quantity through the water injection energy efficiency coupling model and multi-objective collaborative optimization method. The dimensions are consistent in the actual generation of the updated energy-saving control instruction set, so the dimensions of the updated energy-saving control instruction set generation formula are consistent.

[0108] The online fine-tuning and real-time correction of the operating status feedback determine the adjustment direction based on the signs of the components of the water injection pump speed, throttle valve opening, and stratified injection parameters in the dynamic deviation information. The magnitude of a single correction does not exceed the preset adjustment step size (the amount of adjustment to the water injection pump speed, throttle valve opening, and stratified injection parameters each time). After each correction, it is verified whether the tubing operation status meets the safety constraints (the throttle valve pressure drop, the pressure fluctuation intensity of the wellhead, and the flow velocity and pressure difference of the water injection tubing section between the throttle valve and the water injection tubing obtained by inversion do not exceed their respective preset safety values). If the limits are exceeded, the correction is canceled. Fine-tuning is only triggered when a same-direction deviation is detected in two consecutive sampling cycles, and a low-pass filter is applied before the command output to suppress high-frequency jitter, generating an updated energy-saving control command set.

[0109] The preset safety value is obtained by combining the allowable pressure drop, allowable strength, allowable flow velocity and allowable differential pressure of the throttle valve, the wellhead and the water injection string with the statistical distribution of the energy-saving control instruction set, and is set during initialization and dynamically updated in segments according to the water injection conditions.

[0110] In summary, this invention achieves dynamic characteristic generation of the operating status and local energy consumption of throttle valves, wellhead, and water injection tubing by constructing a water injection energy efficiency coupling model, providing input for multi-objective collaborative optimization, and ensuring that control commands take into account both energy consumption minimization and tubing safety constraints; by utilizing operating status feedback to correct the water injection operating status online, it achieves dynamic updating of the energy-saving control command set, ensuring that the water injection process continuously adapts to the actual operating conditions of the tubing, and effectively improving the water injection energy efficiency and operational stability of offshore oilfields.

[0111] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An energy-saving optimization and control method based on offshore oilfield water injection tubing, characterized in that: include, The operating status data of the throttle valve and the wellhead in the entire tubing flow channel of the water injection well are extracted synchronously, and the response inversion is performed based on the flow channel model of the water injection tubing and the operating status data to obtain the characterization signal of the operating status of the entire flow channel. The characterization signal of the entire flow channel operation status is denoised to obtain a denoised characterization signal of the entire flow channel operation status. Based on the characterization signal of the entire flow channel operating state after denoising, the dynamic characteristics of the fluid state and local energy consumption of the entire tubular flow channel are generated through a water injection energy efficiency coupling model. The specific construction process is as follows: A water injection energy efficiency coupling model is constructed based on the whole tubing operation status perception layer, structure and status alignment layer, status and energy consumption coupling layer, and status and structure association solidification layer. The whole tubing string operation status sensing layer synchronously extracts the operation status data of the throttle valve, production tree and water injection string in the whole tubing string flow channel of the water injection well to obtain the original status time series data; The structure and state alignment layer performs time delay compensation processing on the original state time series data to obtain a set of local state fragments. The state and energy consumption coupling layer analyzes the dynamic characteristics of pressure and flow in the set of local state segments to identify the operating state and extract energy dissipation, thereby obtaining the dynamic characteristic sequence of local energy consumption. The state-structure association solidification layer performs consistency screening on the state response characteristics corresponding to multiple operations under the same water injection conditions in the dynamic feature sequence, removes abnormal items with deviations, obtains the state-structure coupling relationship framework, and constructs the water injection energy efficiency coupling model. Based on dynamic characteristics and reservoir water injection requirements, a multi-objective collaborative optimization method with energy consumption minimization as the objective and tubing operation status as a safety constraint is adopted to generate an energy-saving control instruction set. Based on the energy-saving control instruction set, the water injection pump speed, throttle valve opening and stratified injection parameters are dynamically adjusted to generate the water injection operation status. The water injection operation status is corrected online by utilizing operational status feedback to obtain an updated set of energy-saving control instructions.

2. The energy-saving optimization and control method based on offshore oilfield water injection tubing as described in claim 1, characterized in that: The specific steps for obtaining the characterization signal of the entire flow channel's operating state are as follows: The operating status data of the throttle valve and the wellhead in the entire tubing of the water injection well are extracted synchronously at all times to obtain multi-channel raw operating status data; The flow channel status is fused from the original operating status data of multiple channels. With time delay compensation, the flow channel pressure gradient, velocity distribution and energy dissipation characteristics are inverted based on the data nodes available in the upstream and downstream, and a characterization signal of the entire flow channel operating status is generated.

3. The energy-saving optimization and control method based on offshore oilfield water injection tubing as described in claim 2, characterized in that: The operational status information refers to the status signals generated by the throttle valve and the wellhead under the action of fluid, reflecting the operational status and energy dissipation, and combined with the water injection channel section between the throttle valve and the formation inlet obtained by inversion, characterized by a combination of pressure fluctuation characteristics and flow stability indicators.

4. The energy-saving optimization and control method based on offshore oilfield water injection tubing as described in claim 3, characterized in that: The noise reduction process is performed on the characterization signal of the entire flow channel operation state to obtain a denoised characterization signal of the entire flow channel operation state. The specific steps are as follows: The data filtering method is used to suppress interference components in the characterization signal of the entire flow channel operation state, and to obtain the initially separated state components; Based on the flow channel fluid state obtained by inversion from the throttle valve, the wellhead, and the water injection tubing, feature enhancement processing is performed on the state components to obtain a denoised full-flow channel operation state characterization signal of the full tubing flow channel fluid state information.

5. The energy-saving optimization and control method based on offshore oilfield water injection tubing as described in claim 1, characterized in that: The characterization signal based on the denoised full-channel operating state is used to generate dynamic characteristics of the fluid state and local energy consumption of the entire tubular flow channel through a water injection energy efficiency coupling model. The specific steps are as follows. Based on the characterization signal of the denoised full-channel operation status, the operation status data of the throttle valve and the wellhead are processed by component separation to obtain characteristic state segments. Based on the characteristic state segments, the structure-fluid coupling analysis method is used to jointly analyze the pressure gradient, flow stability and energy dissipation characteristics of the water injection channel section between the throttle valve and the formation obtained by inversion, so as to obtain the dynamic characteristics characterizing the fluid state and local energy consumption of the entire tubing channel.

6. The energy-saving optimization and control method based on offshore oilfield water injection tubing as described in claim 1, characterized in that: The reservoir water injection demand refers to dynamic water injection based on the water injection pressure, injection volume, and interlayer water absorption capacity differences of offshore oilfield reservoirs.

7. The energy-saving optimization and control method based on offshore oilfield water injection tubing as described in claim 1, characterized in that: Based on dynamic characteristics and formation water injection requirements, a multi-objective collaborative optimization method is adopted, with energy consumption minimization as the objective and tubing operation status as a safety constraint, to generate an energy-saving control instruction set. The specific steps are as follows. Based on dynamic characteristics and formation water injection requirements, with total water injection energy consumption as the optimization objective, a multi-objective collaborative optimization method is adopted to jointly weigh the pressure drop of the throttle valve, the pressure fluctuation intensity of the wellhead, and the flow velocity of each water injection channel section between the throttle valve and the formation obtained by inversion, so as to obtain a feasible combination of controllable parameters with the minimum total energy consumption, thus forming a feasible controllable parameter space. Based on the feasible controllable parameter space, the pump speed, throttle valve opening and stratified injection parameters are optimized in a coordinated manner to generate an energy-saving control instruction set.

8. The energy-saving optimization and control method based on offshore oilfield water injection tubing as described in claim 1, characterized in that: The process of dynamically adjusting the water injection pump speed, throttle valve opening, and tiered injection parameters based on the energy-saving control instruction set to generate the water injection operation status is as follows: Based on the energy-saving control instruction set, the water injection pump speed, throttle valve opening and stratified injection parameters are synchronously adjusted to obtain the water injection execution parameters. The water injection execution parameters are dynamically executed and adapted to the flow regime to obtain a water injection operation state consistent with the energy-saving control instruction set.

9. The energy-saving optimization and control method based on offshore oilfield water injection tubing as described in claim 1, characterized in that: The specific steps for utilizing operational status feedback to online correct the water injection operation status and obtain an updated energy-saving control instruction set are as follows. Based on the extracted operating status data of the throttle valve, the wellhead, and the water injection tubing, and combined with the characterization signal of the entire flow channel operating status obtained by inverting the operating status data of the throttle valve and the wellhead, the deviation of the water injection operating status is corrected online to obtain the dynamic deviation information between the water injection operating status and the state response. Based on dynamic deviation information, the energy-saving control instruction set is fine-tuned online using operational status feedback to obtain an updated energy-saving control instruction set.

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