Geothermal well group water head mutual resistance regulation method

Abstract

The application provides a geothermal well group water head mutual resistance regulation method, comprising the following steps: constructing a geothermal well group and heat supply pipe network integrated digital twin model; collecting water level, pressure, flow, well pump operation frequency, pipeline resistance, and regulating valve opening operation data of each geothermal well in real time; analyzing geothermal well group dynamic hydraulic coupling and water head mutual resistance by means of the digital twin model; outputting control instructions to drive the operation of the well pump and the regulating valve; continuously collecting the operation data and feeding back to the digital twin model, and calculating the deviation between the measured data and the calculated value of the hydraulic mechanism mathematical model. The geothermal well group water head mutual resistance regulation method provided by the application aims to solve the problems of water head mutual resistance and hydraulic imbalance in the prior art, and the existing manual regulation method cannot dynamically eliminate interference, which not only has high energy consumption, but also aggravates equipment wear and tear and increases operation and maintenance costs.

Description

Technical Field

[0001] This invention belongs to the field of geothermal development technology, specifically relating to a method for regulating the mutual resistance of water head in a geothermal well group. Background Technology

[0002] In geothermal centralized heating systems, to meet the heating demands of large areas and high loads, a well group operation mode is commonly adopted, where multiple geothermal wells are connected in parallel to the same main pipeline network. When multiple heat sources share the pipeline network junction node, due to differences in the geographical location of each geothermal well, well pump parameters, water pipeline length, pipe diameter, pipeline resistance, and equipment operating conditions, complex hydraulic coupling occurs between the well group branches, resulting in head mutual resistance (i.e., the output pressure and flow rate of the near-end geothermal well are high, while the output pressure and flow rate of the far-end geothermal well are insufficient due to the pressure at the front end, making it difficult to reach the design value), and the total flow rate of the overall system is consistently lower than the design standard.

[0003] Currently, the industry primarily addresses the hydraulic imbalance problem in parallel geothermal well groups by manually adjusting valve openings and fixing pump operating frequencies on-site. This approach only achieves phased and localized hydraulic compensation and cannot identify the dynamic changes in head resistance and coupling interference between well groups in real time. To offset the flow loss caused by head resistance, well pumps in the well group need to operate at high loads far from their rated operating conditions for extended periods, leading to increased pump consumption and overall system energy consumption. Long-term operation of pumps, valves, and other equipment under suboptimal conditions accelerates component aging, shortens equipment lifespan, and increases the difficulty and cost of geothermal system operation and maintenance, hindering the long-term sustainable development of geothermal resources. Summary of the Invention

[0004] This invention provides a method for regulating the mutual resistance of water head in a geothermal well group, which aims to solve the problems of mutual resistance of water head and hydraulic imbalance that easily occur in the parallel heating of geothermal well groups in the prior art. Existing manual regulation methods cannot dynamically eliminate interference, which not only consumes a lot of energy, but also aggravates equipment wear and increases operation and maintenance costs.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: to provide a method for regulating the mutual resistance of water head in a geothermal well group, comprising: An integrated digital twin model of geothermal well clusters and heating pipe network is constructed. The digital twin model includes a three-dimensional geometric model of geothermal wells, well pumps, regulating valves, water pipelines, a hydraulic mechanism mathematical model, and data acquisition points. Real-time data collection of water level, pressure, flow rate, well pump operating frequency, pipeline resistance, and regulating valve opening of each geothermal well enables synchronous mapping of data between the on-site physical operating equipment and the digital twin model; By using a digital twin model to analyze the dynamic hydraulic coupling effect and head resistance of the geothermal well group, the operating frequency of each well pump, pipeline flow rate and the opening degree of the regulating valve are determined. The system outputs control commands to drive the well pumps and regulating valves in the field. The control commands include the operating frequency commands for each well pump and the opening commands for each regulating valve. The system collects the pressure values ​​at the confluence point in real time and feeds them back to the digital twin model. The model compares the pressure values ​​with the preset target pressure value and iteratively corrects the control commands based on the comparison deviation, so that the pressure of each well at the confluence point approaches the preset target pressure value until the deviation meets the set threshold. The system also suppresses the head mutual resistance caused by parallel operation. The system continuously collects operational data and transmits it back to the digital twin model. Based on the deviation between the measured data and the calculated values ​​of the hydraulic mechanism mathematical model, it dynamically and iteratively updates the internal physical state parameters of the digital twin model and regenerates the next round of control commands based on the updated state of the digital twin model.

[0006] In one possible implementation, the three-dimensional geometric model layer constructs a 1:1 scale three-dimensional model of the geothermal well, the well pump, the water pipeline, the regulating valve, the well pump pipe section, and the confluence node. The pipe length, pipe diameter, pipe material roughness of the water pipeline, the well pump pipe section, and the confluence node, as well as the static attributes of the regulating valve parameters, are recorded. The model, rated operating parameters, and installation location information of the well pump are also recorded.

[0007] In one possible implementation, the hydraulic mechanism mathematical model includes a branch hydraulic resistance model library and a pump characteristic curve fitting model, and constructs flow conservation constraint equations and confluence node pressure equalization constraint equations.

[0008] In one possible implementation, the equalization constraint equation for the bus node is: ; in, For well pump head; This refers to the resistance loss of the pump pipe; This refers to the resistance loss of the water pipeline; The density of well water; This is the acceleration due to gravity.

[0009] In one possible implementation, the equalization constraint equation of the merge node, ; ; in, For the friction ratio module of the pump tube; This refers to the length of the pump pipe; This is the local resistance coefficient of the pump pipe; For the friction ratio module of the water pipeline; This refers to the length of the water pipeline; This is the local resistance coefficient of the water pipeline.

[0010] In one possible implementation, the along-the-path ratio module is: ; in, This is the friction coefficient along the friction path; Volumetric flow rate; This refers to the inner diameter of the pipe.

[0011] In one possible implementation, iteratively correcting the control command based on the comparison deviation includes: When the resistance of a certain branch pipeline is too high, the operating frequency of the well pump in that branch is increased to make up for the resistance loss. When the resistance of a certain branch pipeline is too low, reduce the operating frequency of the well pump in that branch and adjust the opening of the regulating valve in that branch to throttle and stabilize the pressure.

[0012] In one possible implementation, before formally issuing scheduling instructions, the optimal operating frequency and regulating valve opening combination of various thermal wells under different total water production and different confluence point target pressures are simulated in advance based on the digital twin model, and the simulation results are output for scheduling decision reference.

[0013] One possible implementation also includes acquiring external electricity price signals or load demand signals; during off-peak electricity periods or periods of low load demand, optimizing the operating conditions of thermal wells in various locations based on the digital twin model, and adjusting the operating frequency of each well pump and the opening of the regulating valve.

[0014] In one possible implementation, the system also includes monitoring the changing trends over time based on the dynamically iteratively updated resistance coefficients and pump characteristic curve parameters of each pipeline segment in the digital twin model; issuing a warning of scaling or blockage when the resistance coefficient of a certain pipeline segment exceeds the preset normal range; issuing a warning of pump efficiency degradation when the characteristic curve parameters of a certain pump deviate from the preset normal range; and issuing a valve jamming warning when the deviation between the actual opening degree and the commanded opening degree of a certain regulating valve exceeds a preset threshold.

[0015] The beneficial effects of the geothermal well group head mutual resistance regulation method provided by the present invention are as follows: Compared with the prior art, relying on digital twins to reproduce the hydraulic conditions of the pipeline network in real time, it can identify the dynamic hydraulic coupling and head mutual resistance state of the well group, realize the reasonable distribution of flow by unifying the pressure of the confluence node, and make the pressure of geothermal well water flow in each region consistent at the confluence node of the pipeline network through closed-loop regulation, weaken the head mutual resistance phenomenon caused by the parallel operation of multiple wells, eliminate the hydraulic imbalance problem of near-end flow grabbing and far-end underflow, ensure the hydraulic balance of the entire heating pipeline network, and improve the stability of heating.

[0016] During the control process, the system continuously collects on-site operating data and transmits it back to the digital twin model, dynamically updates the internal operating parameters of the model, and continuously corrects control parameters such as pump frequency, flow rate, and valve opening based on the measured operating condition deviation. This forms a closed-loop control process of data acquisition, analysis and calculation, command issuance, and feedback correction, thereby achieving adaptive dynamic adjustment of pipeline network operating conditions, avoiding pumps, valves, and other equipment from working under abnormal conditions for a long time, slowing down the aging rate of equipment components, and reducing the probability of equipment failure.

[0017] This ensures that the well pump always operates within its high-efficiency range, significantly reducing its power consumption and achieving energy-saving operation of the system. Simultaneously, it avoids the need for repeated on-site manual adjustments, reducing manual maintenance workload and costs, and supporting the long-term stable and sustainable operation of the geothermal system.

[0018] No manual on-site monitoring or debugging is required. Relying on a digital twin model, it completes working condition analysis, parameter calculation, and automatic control. It can respond to changes in pipeline conditions in real time, solving the drawbacks of traditional control and regulation that are difficult to implement and can only achieve local compensation, thus improving control accuracy and automation level. Attached Figure Description

[0019] Figure 1 This is a schematic diagram illustrating the steps of the geothermal well group water head mutual resistance control method provided in an embodiment of the present invention. Detailed Implementation

[0020] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0021] It should be noted that the terms "length", "width", "height", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", and "tail" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present 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. Therefore, they should not be construed as limitations on the present invention.

[0022] It should also be noted that, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Additionally, "multiple" and "several" mean two or more, unless otherwise explicitly specified.

[0024] Please see Figure 1 The present invention will now describe the method for regulating the mutual resistance of water head in a geothermal well group. The method for regulating the mutual resistance of water head in a geothermal well group includes the following steps: S100. Construct an integrated digital twin model of geothermal well clusters and heating pipe networks. The digital twin model includes a three-dimensional geometric model of geothermal wells, well pumps, regulating valves, water pipelines, a hydraulic mechanism mathematical model, and data acquisition points. S200: Real-time acquisition of water level, pressure, flow rate, well pump operating frequency, pipeline resistance, and regulating valve opening data of each geothermal well, realizing synchronous mapping of data between the on-site physical operating equipment and the digital twin model; S300. Using a digital twin model, analyze the dynamic hydraulic coupling effect and head resistance of the geothermal well group to determine the operating frequency of each well pump, pipeline flow rate, and the opening degree of the regulating valve. S400: Output control commands to drive the well pumps and regulating valves in the field. The control commands include the operating frequency commands of each well pump and the opening commands of the regulating valves. The pressure values ​​at the confluence point are collected in real time and fed back to the digital twin model. The model is compared with the preset target pressure value. The control commands are iteratively corrected based on the comparison deviation, so that the pressure of each well at the confluence point approaches the preset target pressure value until the deviation meets the set threshold. The system also suppresses the head mutual resistance caused by parallel operation. S500: Continuously collect the operating data and transmit it back to the digital twin model. Based on the deviation between the measured data and the calculated values ​​of the hydraulic mechanism mathematical model, dynamically iterate and update the internal physical state parameters of the digital twin model, and regenerate the next round of control commands based on the updated state of the digital twin model.

[0025] In this embodiment, an integrated digital twin model of the geothermal well group and the heating pipeline network is first constructed. This model integrates three modules: the three-dimensional geometric model of the field equipment (covering geothermal wells, well pumps, regulating valves, water pipelines, etc.), the hydraulic mechanism mathematical model, and the data acquisition points.

[0026] The 3D geometric model recreates the spatial structure of the geothermal well body, pump, regulating valve, water pipeline, and network junction nodes at a 1:1 scale based on the actual site dimensions. The hydraulic mechanism mathematical model incorporates computational logic for hydraulic resistance, pump characteristics, flow and pressure constraints, providing computational support for hydraulic condition analysis and parameter calculation. Data acquisition points correspond to various on-site sensors, ensuring data interoperability between the site and the digital model.

[0027] During system operation, real-time data such as well water level, outlet pressure, pipeline flow, well pump operating frequency, pipeline resistance, and regulating valve opening are collected from various locations via field sensors and acquisition terminals. This data is then integrated into the digital twin model in real time to achieve synchronous mapping between the physical equipment operating status and the digital model status, ensuring that the model can reflect the real-time hydraulic conditions of the pipeline network.

[0028] Based on synchronized field data, the digital twin model analyzes the dynamic hydraulic coupling relationship between multiple wells and the degree of mutual head resistance. Combined with the overall heating load and hydraulic balance requirements of the pipeline network, it calculates and determines the target operating frequency of each well pump, the flow rate of each branch pipeline, and the target opening degree of the corresponding regulating valve, forming a complete set of control parameters that match the current operating conditions.

[0029] The system converts the calculated control parameters into control commands and sends them to the field well pumps and regulating valves, controlling the operating frequency of each well pump and the opening of the regulating valves. Real-time pressure values ​​at the confluence points are collected and fed back to the digital twin model, compared with a preset target pressure value. Control commands are iteratively corrected based on the deviation, ensuring that the pressure at each well at the confluence point approaches the preset target pressure value until the deviation meets a set threshold. This ensures consistent pressure at the confluence nodes of the pipeline network for hot water from various wells, reducing head resistance caused by parallel operation of multiple wells and eliminating hydraulic imbalance problems such as near-end flow competition and far-end underflow.

[0030] During the control process, operational data is continuously collected and transmitted back to the digital twin model. Based on the deviation between the measured data and the calculated values ​​from the hydraulic mechanism mathematical model, the internal physical state parameters of the digital twin model are dynamically and iteratively updated. The next round of control commands is then regenerated based on the updated digital twin model state. This forms a closed-loop control process of data acquisition, analysis and calculation, command issuance, and feedback correction, ensuring that the geothermal well network maintains a stable and balanced hydraulic operation.

[0031] The geothermal well group head mutual resistance control method provided in this embodiment of the invention, compared with the prior art, relies on digital twin to reproduce the hydraulic conditions of the pipeline network in real time. It can identify the dynamic hydraulic coupling and head mutual resistance state of the well group, realize the reasonable distribution of flow by unifying the pressure of the confluence node, and ensure that the pressure of the geothermal well water flow at the confluence node of the pipeline network is consistent through closed-loop regulation. This reduces the head mutual resistance phenomenon caused by the parallel operation of multiple wells, eliminates the hydraulic imbalance problem of near-end flow grabbing and far-end underflow, ensures the hydraulic balance of the entire heating pipeline network, and improves the stability of heating.

[0032] During the control process, the system continuously collects on-site operating data and transmits it back to the digital twin model, dynamically updates the internal operating parameters of the model, and continuously corrects control parameters such as pump frequency, flow rate, and valve opening based on the measured operating condition deviation. This forms a closed-loop control process of data acquisition, analysis and calculation, command issuance, and feedback correction, thereby achieving adaptive dynamic adjustment of pipeline network operating conditions, avoiding pumps, valves, and other equipment from working under abnormal conditions for a long time, slowing down the aging rate of equipment components, and reducing the probability of equipment failure.

[0033] This ensures that the well pump always operates within its high-efficiency range, significantly reducing its power consumption and achieving energy-saving operation of the system. Simultaneously, it avoids the need for repeated on-site manual adjustments, reducing manual maintenance workload and costs, and supporting the long-term stable and sustainable operation of the geothermal system.

[0034] No manual on-site monitoring or debugging is required. Relying on a digital twin model, it completes working condition analysis, parameter calculation, and automatic control. It can respond to changes in pipeline conditions in real time, solving the drawbacks of traditional control and regulation that are difficult to implement and can only achieve local compensation, thus improving control accuracy and automation level.

[0035] It should be noted that pipeline resistance includes the well pump section, water delivery pipeline, and related fittings. The well pump section refers to the water delivery string from the outlet of the downhole pump to the wellhead. The water delivery pipeline refers to all surface water delivery pipelines from the wellhead to the junction of the pipeline network. Related fittings refer to components on two connected pipeline sections that generate localized resistance, such as elbows, tees, reducers, and valve connections. Pipeline resistance is the sum of the resistances of all the pipeline components.

[0036] Data synchronization mapping refers to transmitting real-time operating data of hot wells, pumps, regulating valves, and pipelines collected on-site to the corresponding virtual units of the digital twin model. This ensures that the operating parameters of the digital model are consistent with the actual operating conditions of the physical equipment on-site, achieving a one-to-one correspondence and synchronous update between the physical equipment on-site and the digital model.

[0037] In some embodiments, the three-dimensional geometric model layer constructs a three-dimensional model of the geothermal well, well pump, water pipeline, regulating valve, well pump pipe section and confluence node at a 1:1 scale. The pipe length, pipe diameter, pipe material roughness and regulating valve parameters of the water pipeline, well pump pipe section and confluence node are recorded, and the well pump model, rated operating parameters and installation location information are recorded.

[0038] In this embodiment, the 3D geometric model layer is constructed according to the actual size and spatial layout of the on-site geothermal well group heating system. A 1:1 scale model is built, including geothermal wells, well pumps, well pump pipe sections, water pipelines, regulating valves, and network confluence nodes. The well pump pipe section is the downhole water supply string extending from the well pump outlet to the geothermal well head. The confluence node is the common connection node where each branch of a single well merges into the main heating network. Through 1:1 scale modeling, the pipeline routing, equipment layout, and spatial structure of the on-site system are fully reproduced, ensuring a one-to-one correspondence between the digital model and the geometric shape of the physical site.

[0039] After the 3D model is built, standardized static parameters are entered into the model. These include the pipe length, diameter, and inner wall roughness of each section of water pipeline, well pump section, and confluence node; valve parameters such as model, nominal diameter, opening range, and resistance characteristics of each branch regulating valve; and rated operating parameters for each well pump, including model, rated flow rate, rated head, rated power, and rated operating frequency, as well as the installation elevation and location information of the well pumps.

[0040] The 1:1 model fully covers all water transmission channels and equipment from the downhole pump pipe to the surface pipeline network, providing a precise geometric basis for subsequent head resistance analysis and hydraulic condition simulation, ensuring that the model calculation results match the actual on-site conditions.

[0041] In some embodiments, please refer to Figure 1 The hydraulic mechanism mathematical model includes a branch hydraulic resistance model library and a pump characteristic curve fitting model, and constructs flow conservation constraint equations and pressure equalization constraint equations at the confluence nodes. In this embodiment, the branch hydraulic resistance model library constructs an independent hydraulic resistance calculation model for each water transmission branch corresponding to each geothermal well, and then summarizes them to form the branch hydraulic resistance model library.

[0042] Each branch model performs real-time calculations of friction loss and local resistance loss for the well pump section and the surface water transmission pipeline. Based on pre-entered static parameters such as pipeline inner diameter, pipe roughness, pipe length, and local resistance coefficient, and combined with the current real-time pipeline flow rate, the total pipeline resistance loss under the current operating condition is calculated iteratively using hydraulic friction loss formulas and local resistance formulas. This accurately characterizes the resistance characteristics of each branch under different flow conditions, providing basic data for head resistance analysis and head demand calculation.

[0043] The pump characteristic curve fitting model, based on the rated operating parameters of each well pump, generates the flow-head (QH) characteristic curve of the well pump at its rated frequency. It also incorporates the pump frequency conversion similarity law to establish a conversion logic for frequency conversion conditions. When the well pump's operating frequency changes, the model can automatically convert the flow-head curve to the corresponding frequency, matching the output head and operating flow rate corresponding to the current pump frequency in real time. Furthermore, it can reverse-engineer the target operating frequency of the well pump based on the target head required for the branch, providing a quantitative calculation basis for pump frequency regulation.

[0044] The flow conservation constraint equation is: the total system water supply flow rate equals the sum of the output flow rates of the heat well branches in each region. This equation serves as the fundamental constraint for flow distribution within the well group, ensuring that the sum of the distributed flow rates of each individual well always matches the total flow rate demand corresponding to the total heating load of the system, preventing the total flow rate from deviating from the design conditions, and guaranteeing that the overall heating capacity meets the standards.

[0045] The pressure equalization constraint equation at the confluence node ensures that the static head of the water flow from each hot well branch to the confluence node is equal. Specifically, the head of the confluence of a single well branch is equal to the output head of the well pump, minus the resistance loss of the well pump pipe section and the resistance loss of the surface water pipeline. The head of the confluence of all branches is uniformly equal to the set pressure head of the confluence node, avoiding hydraulic coupling interference phenomena such as excessive pressure in near-end wells and crowding out the flow of far-end wells.

[0046] In the above embodiment, the flow conservation constraint equation is: = +……+ +……+ Where Q represents flow rate.

[0047] In some embodiments, the equalization constraint equation for the bus node is: ;in, For well pump head; This refers to the resistance loss of the pump pipe; This refers to the resistance loss of the water pipeline; The density of well water; This is the acceleration due to gravity. In this embodiment, The target static head at the confluence node is the head value that all geothermal well branch water flows must reach when delivered to the confluence node. It is the head height calculated after the set pressure at the confluence node and serves as a unified benchmark for hydraulic balance control.

[0048] The pump output head of the i-th geothermal well is obtained by matching the pump characteristic curve fitting model with the current operating frequency of the pump, and is the total energy source of the water flow in the single well branch.

[0049] The pressure resistance loss of the pump pipe section corresponding to the i-th geothermal well is... The pressure resistance loss of the surface water pipeline corresponding to the i-th geothermal well is calculated by combining the branch hydraulic resistance model library with the pipeline static parameters and real-time flow rate.

[0050] The effective static head of the water delivered from a single well branch to the confluence node is equal to the total head output by the well pump. This is calculated by successively deducting the head loss due to resistance in the well pump section and the head loss due to resistance in the surface water pipeline, leaving the final head energy. In actual control, the system uses the confluence head of all branches as the basis for calculation. Using equality as a constraint and combining the pipeline resistance characteristics of each branch, the target head required by each well pump is calculated in reverse. Then, the target operating frequency of the well pump is obtained by fitting the pump characteristic curve model.

[0051] For branches with excessively large differences in pipeline resistance, where frequency conversion regulation alone cannot match the pressure equalization requirements, the resistance is supplemented by fine-tuning the opening of the electric regulating valve. Ultimately, this ensures that the static pressure head of all branches is consistent at the confluence node, eliminating the mutual head resistance interference of multiple wells in parallel.

[0052] In some embodiments, in the equalization constraint equation of the merge node... ; ;in, For the friction ratio module of the pump tube; This refers to the length of the pump pipe; This is the local resistance coefficient of the pump pipe; For the friction ratio module of the water pipeline; This refers to the length of the water pipeline; This is the local resistance coefficient of the water pipeline.

[0053] In this embodiment, Let be the friction ratio module of the pump pipe for the i-th geothermal well, and be the friction pressure resistance loss per unit length of pump pipe. Its value is determined by the inner diameter of the pump pipe, the roughness of the inner wall of the pipe material, the flow rate of the fluid in the pipe, and the physical properties of the well water. It is a parameter characterizing the friction resistance characteristics of the downhole pump pipe.

[0054] The total length of the pump pipe of the i-th geothermal well corresponds to the total length of the water delivery string from the outlet of the downhole pump to the wellhead of the geothermal well. It is a static basic parameter of the pre-entered three-dimensional geometric model.

[0055] Let be the local resistance coefficient of the pump pipe of the i-th geothermal well, which is the ratio of the total local resistance loss generated by all pipe fittings (including pipe joints, reducers, downhole valves, etc.) within the pump pipe section to the friction loss along the pipe section. This coefficient can be used to convert the dispersed local resistance loss into an equivalent proportion of the friction loss along the pipe section, thereby simplifying the calculation of the total resistance of the pipe section.

[0056] For the i-th geothermal well, the friction ratio module represents the friction pressure resistance loss per unit length of the surface water pipeline. Its value is determined by the nominal inner diameter of the water pipeline, the pipe material, the inner wall roughness, and the real-time flow rate inside the pipe.

[0057] The total length of the surface water pipeline corresponding to the i-th geothermal well is the total length of the surface water pipeline from the geothermal wellhead to the pipe network junction node, which is a static pipeline parameter pre-entered into the model.

[0058] Let be the local resistance coefficient of the surface water pipeline corresponding to the i-th geothermal well, and be the ratio of the total local resistance loss generated by all pipe fittings such as elbows, tees, reducers, and electric regulating valves in this pipe section to the friction loss along the pipe section.

[0059] In actual operation, the branch hydraulic resistance model library updates the friction ratio module values ​​of the pump pipe and water delivery pipeline simultaneously based on real-time collected pipeline flow data. Then, using the aforementioned formulas, the pump pipe resistance loss and water delivery pipeline resistance loss under the current operating conditions are calculated. Substituting the two resistance losses into the pressure equalization constraint equation of the confluence node completes the calculation of the single-well branch confluence head. Since there are significant differences between the underground pump pipe and the surface water delivery pipeline in terms of pipe diameter, material characteristics, length, and fitting configuration, a segmented independent modeling and calculation method is adopted. This method can restore the different resistance characteristics of the two pipeline segments and avoid systematic calculation errors caused by a unified simplified model.

[0060] In some embodiments, the travel ratio module is ;in, This is the friction coefficient along the friction path; Volumetric flow rate; This is the inner diameter of the pipe. In this embodiment, The friction factor is the pipe's friction resistance coefficient, and its value is determined by the roughness of the pipe's inner wall and the flow regime (Reynolds number) of the fluid inside the pipe. Under normal operating conditions of a geothermal heating system, the hot water inside the pipe is mostly in the turbulent rough region. This coefficient can be selected based on empirical values ​​according to the type of pipe material, or iteratively corrected by combining measured data from long-term system operation to adapt to changes in operating conditions such as pipe scaling and inner wall wear.

[0061] Let be the volumetric flow rate within the i-th pipe segment, collected and uploaded in real time by flow sensors deployed on-site. This is a dynamic parameter affecting the magnitude of the friction resistance. The formula shows that the friction resistance of the pipe is positively correlated with the square of the flow rate; fluctuations in flow rate will affect the total resistance of the pipe.

[0062] Let be the inner diameter of the i-th segment of the pipeline, which is a static pipeline parameter pre-entered into the three-dimensional geometric model; the formula shows that the friction resistance is inversely proportional to the fifth power of the inner diameter of the pipeline, and small changes in the pipe diameter will affect the friction resistance of the pipeline.

[0063] For well water density, π represents pi, and all are known physical properties and mathematical constants. The density of well water can be dynamically adjusted according to the actual water temperature. This calculation formula is applicable to the friction ratio module calculation of both downhole pump pipe sections and surface water transmission pipeline sections. Simply substitute the inner diameter, flow rate, friction coefficient, and other parameters of the corresponding pipe section to obtain the friction loss per unit length of the corresponding pipe section.

[0064] In actual operation, the system updates the friction ratio module values ​​of the pump pipe and water delivery pipe synchronously with the formula based on the real-time collected pipeline flow data. Then, by substituting the values ​​into the corresponding resistance loss calculation formula, the total pressure resistance loss of the two pipeline sections under the current operating conditions can be obtained. This provides basic data for the resistance dimension of the iterative solution of the pressure equalization constraint equation of the confluence node.

[0065] In some embodiments, iteratively correcting the control command based on the comparison deviation includes: when the resistance of a branch pipeline is too high, increasing the operating frequency of the well pump in that branch to compensate for the resistance loss; when the resistance of a branch pipeline is too low, decreasing the operating frequency of the well pump in that branch and adjusting the opening of the regulating valve in that branch for throttling-assisted pressure stabilization.

[0066] In this embodiment, the scenarios for determining excessive pipeline resistance include: the natural resistance of the remote geothermal well is excessive due to the long water pipeline and high frictional resistance, or the actual resistance exceeds the initial calculated value due to scaling and increased inner wall resistance in the pipeline after long-term operation of the system. Ultimately, this manifests as the actual head of the water flow from the branch to the confluence node being lower than the target equalizing head.

[0067] At this point, the system prioritizes compensation by increasing the operating frequency of the well pump in that branch. Based on the pump characteristic curve fitting model, the required additional head increment is calculated according to the current resistance deviation value, and the target operating frequency that the well pump needs to increase is obtained by reverse calculation. After the well pump operating frequency is increased, the total output head increases synchronously, which can directly offset the additional pipeline resistance loss, allowing the runoff head of this branch to rise back to the target equal pressure value, achieving pressure unification with other branches. This adjustment process prioritizes well pump frequency conversion as the adjustment means, eliminating the need for additional throttling with regulating valves and avoiding unnecessary energy loss.

[0068] When the resistance of a certain branch pipeline is too low, pressure stabilization is achieved by using a graded adjustment method that primarily reduces the operating frequency of the well pump and secondarily uses the throttling of the regulating valve opening.

[0069] A typical scenario where pipeline resistance is low is near-end geothermal wells. Because the water pipeline is short and the friction resistance is low, the natural resistance is much lower than that of the distant branch. This results in the actual head of the water flowing into the branch being higher than the target equal pressure head, which is also a cause of head mutual obstruction and near-end flow competition.

[0070] The adjustment process is divided into two stages: The first stage prioritizes reducing the operating frequency of the branch pump, directly lowering the branch runoff head by reducing the total pump output head, bringing it closer to the target equal pressure value. This method directly reduces the pump's power consumption and is an energy-saving adjustment measure. Once the pump operating frequency drops to the minimum permissible operating frequency, if the branch runoff head is still higher than the target value, or if fine-tuning of the pressure is required, the second stage of adjustment is initiated. This involves gradually closing the opening of the branch's electric regulating valve, increasing the local resistance of the branch through the valve's throttling effect, consuming excess head energy, and ultimately stabilizing the branch runoff head at the target equal pressure value.

[0071] The above adjustment process is a continuous iterative closed-loop process. After each parameter adjustment, the system continuously collects on-site operating data and recalculates the branch resistance and confluence head deviation. If the deviation still exceeds the allowable threshold, the control parameters are fine-tuned until the confluence head deviation of all branches is controlled within the preset accuracy range, ultimately achieving equal confluence pressure across all branches and dynamically suppressing the head mutual resistance effect of the well group.

[0072] In some embodiments, the geothermal well group water head mutual resistance control method provided by the present invention further includes, before formally issuing the scheduling command, simulating the optimal operating frequency and regulating valve opening combination of each geothermal well under different total water production and different confluence point target pressures based on a digital twin model, and outputting the simulation results for scheduling decision reference.

[0073] In this embodiment, before generating formal scheduling instructions and driving field equipment actions, the system first initiates the simulation calculation mode of the digital twin model, using two types of variables as simulation input boundaries to conduct multi-condition combination simulations. The first type is the total water production of the system, corresponding to the heat load demand under different heating periods and different climatic conditions, which can cover the entire operating range, including off-peak load, design conditions, and peak load. The second type is the target pressure at the confluence point, corresponding to different operating pressure levels of the main pipeline network, and multiple sets of target pressure values ​​can be set according to the pressure-bearing capacity of the pipeline network and the terminal heating pressure difference requirements.

[0074] Meanwhile, the rated parameters of the equipment, static properties of the pipelines, pump characteristic curves, resistance calculation models, and other parameters already entered into the simulation are used as fixed boundary conditions to ensure that the parameters of the virtual simulation model are consistent with those of the actual operating system on site.

[0075] For each combination of total water production and target pressure at the confluence point, the digital twin model relies on the built-in branch hydraulic resistance model library and pump characteristic curve fitting model, combined with the flow conservation constraint equation and the pressure equalization constraint equation at the confluence point, with the optimization objectives of minimizing the total system operating energy consumption and minimizing the hydraulic balance deviation of each branch, and obtains the optimal combination of operating frequency and corresponding branch regulating valve for each geothermal well under the given conditions through iterative solution of optimization algorithm.

[0076] The system synchronously calculates and outputs key operating indicators such as total system power consumption, flow distribution deviation of each branch, equipment operating load rate, and pipeline pressure distribution under this scheme, and fully restores the system operating status after the scheme is implemented.

[0077] After the simulation calculations are completed, the system organizes the simulation results of all operating condition combinations into a multi-scheme comparison dataset, which is output in the form of quantitative reports and operating condition comparisons for dispatching decision-making reference. Dispatchers can select the optimal control scheme from multiple simulation schemes based on actual heating demand, equipment operation and maintenance status, energy-saving assessment targets, and other actual conditions.

[0078] Once the scheme is confirmed to be correct, the corresponding control parameters are converted into formal control commands and sent to the on-site pump and valve equipment for execution. This completes the entire scheduling process of simulation verification, scheme optimization, and implementation, ensuring that the geothermal well group system regulation process is stable and controllable, and solving the problem that traditional on-site commissioning is prone to causing large fluctuations in operating conditions.

[0079] In some embodiments, the geothermal well group head mutual resistance control method provided by the present invention further includes acquiring external electricity price signals or load demand signals. During off-peak electricity periods or periods of low load demand, the operating conditions of each geothermal well are uniformly optimized based on the digital twin model, and the operating frequency of each well pump and the opening degree of the regulating valve are adjusted.

[0080] In this embodiment, external electricity price signals can be obtained by connecting to the power grid marketing system and power dispatching platform to acquire real-time electricity price data, or by pre-entering the local peak-valley time-of-use electricity price time-sharing rules and corresponding price standards. The system compares the current time with the electricity price time-sharing rules in real time, automatically identifies the start and end points of the off-peak electricity period, and synchronously obtains the off-peak electricity price as an economic parameter for optimization calculation.

[0081] The load demand signal can be connected to the heating management and control system and the terminal heat load monitoring platform to obtain real-time heating load data, or combined with outdoor temperature and time period patterns to generate load forecast values, which are then converted into corresponding total water production demand. The system determines whether it is currently in a low load demand period based on the total water production threshold, and uses the total water production demand as a flow constraint condition for hydraulic calculations.

[0082] Once the system identifies a period of off-peak electricity demand or low load demand, it inputs the current electricity price, total water production demand, pipeline pressure limit, and equipment rated parameters as optimization boundary conditions into the digital twin model. The model is based on the fundamental constraints of equal pressure at each branch confluence and hydraulic balance compliance. It utilizes a built-in library of branch hydraulic resistance models and pump characteristic curve fitting models, combined with flow conservation constraint equations and confluence node pressure equalization constraint equations, to execute corresponding optimization logic for the two types of time periods.

[0083] Electricity prices are lower during off-peak hours. The system aims to minimize electricity costs and optimize overall energy efficiency throughout the entire operating cycle. While meeting the total heating demand, the total water production can be appropriately increased by combining the heating system's thermal storage device. Geothermal thermal energy can be stored in the thermal storage equipment for heating during flat and peak periods, reducing the water intake load during periods of high electricity prices.

[0084] During the optimization process, the algorithm iterates through feasible combinations of operating frequencies and regulating valve openings for geothermal wells in various locations, prioritizing wells with high pump efficiency and favorable pipeline resistance characteristics to bear more water production load. Simultaneously, it strictly adheres to the pressure equalization constraints at the confluence nodes, ensuring consistent confluence pressure across all branches to prevent exacerbated head resistance effects and flow distribution imbalances after increasing the total load. Finally, the algorithm iteratively solves for the globally optimal combination of operating parameters adapted to off-peak electricity periods, which is then converted into control commands and sent to the field pumps and valves for execution.

[0085] During periods of low load demand, the total water production demand decreases. If the original well group is maintained in full operation, problems such as low-frequency and inefficient operation of well pumps and prominent head resistance effects under low flow conditions are likely to occur. At this time, the system aims to achieve stable hydraulic balance and high single-well operating efficiency under low load conditions. Based on a digital twin model, the system simulates the operating effects of different well group start-up and shutdown combinations and different parameter configurations to select the best well group operation scheme suitable for the current low load.

[0086] Specifically, some geothermal wells with lower energy efficiency and higher pipeline resistance can be shut down, with the remaining well groups handling the water production load. The operating frequency of the pumps and the opening of the regulating valves in the operating wells are adjusted simultaneously to ensure equal pressure in each operating branch even under low total flow conditions, suppressing hydraulic imbalance at low flow rates. This also keeps the pumps operating within their rated high-efficiency range, preventing a significant drop in pump efficiency and an increase in energy consumption per unit of water produced under low load. Furthermore, this reduces operating electricity costs while meeting heating demands.

[0087] In some embodiments, the geothermal well group head mutual resistance control method provided by the present invention further includes monitoring the changing trends over time based on the dynamically iteratively updated resistance coefficients and pump characteristic curve parameters of each pipeline segment in a digital twin model. When the resistance coefficient of a certain pipeline segment exceeds a preset normal range, a warning of pipeline scaling or blockage is issued. When the characteristic curve parameter of a certain pump deviates from a preset normal range, a warning of pump efficiency decline is issued. When the deviation between the actual opening degree and the commanded opening degree of a certain regulating valve exceeds a preset threshold, a valve jamming warning is issued.

[0088] In this embodiment, during the daily closed-loop control operation of the system, the digital twin model will, based on real-time collected operating data such as pipeline flow, inlet and outlet pressure, well pump operating frequency, and actual valve opening, combined with the built-in hydraulic mechanism calculation model, reverse iteratively correct the actual resistance coefficient of each pipeline section and the actual characteristic curve parameters of each well pump, while simultaneously recording the command opening degree of each valve control and the actual opening value fed back from the field.

[0089] The system establishes a time-dimensional operational database for the parameters of the aforementioned pipelines, well pumps, and regulating valves, continuously tracking the daily, weekly, and monthly trends of these parameters. Simultaneously, based on the equipment's factory parameters and stable operational data from the system commissioning phase, it sets normal operating ranges and deviation warning thresholds for each parameter, serving as the benchmark for fault diagnosis.

[0090] Pipeline scaling or blockage warning: During long-term operation of geothermal well water supply systems, minerals in the groundwater are prone to deposit on the pipe walls to form scale, or debris may accumulate and cause local blockage of the pipeline. This is visually manifested as a continuous and abnormal increase in the pipeline resistance coefficient.

[0091] The system dynamically iterates and compares the actual resistance coefficient of each pipeline segment with the preset normal resistance coefficient range. When the resistance coefficient of a pipeline segment exceeds the upper limit of the normal range and shows a continuous upward trend, it determines that the pipeline has a risk of scaling or blockage. It then issues a scaling / blockage warning, simultaneously marking the location of the faulty pipeline and the magnitude of the resistance deviation, reminding maintenance personnel to promptly carry out pipeline cleaning, blockage investigation, and other maintenance work. Simultaneously, the system can predict the degree of scaling development based on the rate of increase in the resistance coefficient, assisting in the formulation of preventative maintenance plans.

[0092] Pump efficiency degradation warning: During long-term operation, well pumps are prone to problems such as impeller wear, seal aging, and component corrosion, which lead to a decline in the actual output performance of the well pump. This is manifested in the pump's characteristic curve parameters deviating from the initial reference value, and the output head and flow rate being lower than the design value at the same operating frequency, resulting in a continuous decline in operating efficiency.

[0093] The system backfits the actual characteristic curve of the well pump under the current operating conditions using real-time operating data, and compares the fitted characteristic curve parameters with the preset normal parameter range. When the characteristic curve parameters of a well pump deviate from the normal range and the performance degradation exceeds the allowable threshold, it is determined that the well pump has an efficiency degradation fault, and a pump efficiency degradation warning is issued, prompting maintenance personnel to promptly carry out well pump maintenance, impeller cleaning, or component replacement to avoid long-term inefficient operation of the well pump leading to a significant increase in system energy consumption.

[0094] Valve jamming warning: Electric regulating valves are the core actuators for hydraulic balance control. During long-term operation, problems such as valve core scaling, transmission mechanism jamming, and actuator failure are prone to occur. This manifests as an excessive deviation between the actual valve opening and the control command opening, making it unable to accurately respond to the control command, thus affecting the accuracy of hydraulic balance control.

[0095] After each control command to adjust the valve opening is issued, the system collects the actual feedback valve opening in real time and compares the commanded opening with the actual opening. When the deviation between the two continuously exceeds the preset allowable deviation threshold, or when the valve response lags behind for more than a specified time, the system determines that the control valve has a jamming fault and immediately issues a valve jamming warning, reminding maintenance personnel to promptly inspect, lubricate, or clean the valve to ensure the control valve's adjustment accuracy and response performance, and maintain the reliability of closed-loop control.

[0096] Real-time reflection of the actual health status of equipment is the foundation for proactive fault prediction and maintenance.

[0097] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for regulating the mutual resistance of water head in a geothermal well group, characterized in that, Includes the following steps: An integrated digital twin model of geothermal well clusters and heating pipe network is constructed. The digital twin model includes a three-dimensional geometric model of geothermal wells, well pumps, regulating valves, water pipelines, a hydraulic mechanism mathematical model, and data acquisition points. Real-time data collection of water level, pressure, flow rate, well pump operating frequency, pipeline resistance, and regulating valve opening of each geothermal well enables synchronous mapping of data between the on-site physical operating equipment and the digital twin model; By using a digital twin model to analyze the dynamic hydraulic coupling effect and head resistance of the geothermal well group, the operating frequency of each well pump, pipeline flow rate and the opening degree of the regulating valve are determined. The output control commands drive the well pumps and regulating valves in the field to operate. The control commands include the operating frequency commands of each well pump and the opening commands of the regulating valves. The pressure value at the confluence point is collected in real time and fed back to the digital twin model. It is compared with the preset target pressure value. The control command is iteratively corrected according to the comparison deviation, so that the pressure of each well at the confluence point approaches the preset target pressure value until the deviation meets the set threshold; suppressing the head mutual resistance caused by parallel operation; The system continuously collects operational data and transmits it back to the digital twin model. Based on the deviation between the measured data and the calculated values ​​of the hydraulic mechanism mathematical model, it dynamically and iteratively updates the internal physical state parameters of the digital twin model and regenerates the next round of control commands based on the updated state of the digital twin model.

2. The method for regulating the mutual resistance of water head in a geothermal well group as described in claim 1, characterized in that, The three-dimensional geometric model layer is built at a 1:1 scale, depicting the geothermal well, the well pump, the water pipeline, the regulating valve, the well pump pipe section, and the confluence node. The pipe length, pipe diameter, pipe material roughness of the water pipeline, the well pump pipe section, and the confluence node, as well as the static attributes of the regulating valve parameters, are recorded. The model, rated operating parameters, and installation location information of the well pump are also recorded.

3. The method for regulating the mutual resistance of water head in a geothermal well group as described in claim 1, characterized in that, The hydraulic mechanism mathematical model includes a branch hydraulic resistance model library and a pump characteristic curve fitting model, and constructs flow conservation constraint equations and pressure equalization constraint equations at the confluence nodes.

4. The method for regulating the mutual resistance of water head in a geothermal well group as described in claim 3, characterized in that, The equalization constraint equation for the merge node is: ; in, For well pump head; This refers to the resistance loss of the pump pipe; This refers to the resistance loss of the water pipeline; The density of well water; This is the acceleration due to gravity.

5. The geothermal well group head mutual resistance control method as described in claim 4, characterized in that, In the pressure equalization constraint equation of the merge node ; ; in, For the friction ratio module of the pump tube; This refers to the length of the pump pipe; This is the local resistance coefficient of the pump pipe; For the friction ratio module of the water pipeline; This refers to the length of the water pipeline; This is the local resistance coefficient of the water pipeline.

6. The geothermal well group head mutual resistance control method as described in claim 5, characterized in that, The friction ratio module is ; in, This is the friction coefficient along the friction path; Volumetric flow rate; This refers to the inner diameter of the pipe.

7. The method for regulating the mutual resistance of water head in a geothermal well group as described in claim 1, characterized in that, The step of iteratively correcting the control command based on the comparison deviation includes: When the resistance of a certain branch pipeline is too high, the operating frequency of the well pump in that branch is increased to make up for the resistance loss. When the resistance of a certain branch pipeline is too low, reduce the operating frequency of the well pump in that branch and adjust the opening of the regulating valve in that branch to throttle and stabilize the pressure.

8. The method for regulating the mutual resistance of water head in a geothermal well group as described in claim 1, characterized in that, It also includes, before officially issuing dispatch instructions, using the digital twin model to pre-simulate the optimal operating frequency and regulating valve opening combination of various thermal wells under different total water production and different target pressures at different confluence points, and outputting simulation results for dispatch decision-making reference.

9. The method for regulating the mutual resistance of water head in a geothermal well group as described in claim 1, characterized in that, It also includes acquiring external electricity price signals or load demand signals; and during off-peak electricity periods or periods of low load demand, optimizing the operating conditions of thermal wells in various locations based on the digital twin model, and adjusting the operating frequency of each well pump and the opening of the regulating valve.

10. The method for regulating the mutual resistance of water head in a geothermal well group as described in claim 1, characterized in that, It also includes monitoring the changing trend of the resistance coefficient and pump characteristic curve parameters of each pipeline segment based on the dynamically iteratively updated parameters in the digital twin model; when the resistance coefficient of a certain pipeline segment exceeds the preset normal range, a warning of pipeline scaling or blockage is issued. When the characteristic curve parameters of a pump deviate from the preset normal range, a pump efficiency decline warning is issued; when the deviation between the actual opening degree and the commanded opening degree of a regulating valve exceeds the preset threshold, a valve jamming warning is issued.

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