Geothermal reservoir anti-blocking and energy storage coordination system and control method

Abstract

The geothermal reservoir anti-blocking and energy storage coordination system and control method include a green electricity supply unit, a heat storage unit having an electric heating module, the electric heating module being electrically connected with the green electricity supply unit, the green electricity supply unit supplying power to the electric heating module, the electric heating module being used for heating the recharge water in the heat storage unit, and a recharge unit connected to the heat storage unit, the recharge unit being used for delivering the recharge water output by the heat storage unit to an injection well for recharging. The green electricity supply unit is used to supply power to the electric heating module, so that the recharge water in the heat storage unit can reach a high temperature before being input into the injection well, thereby reducing the temperature difference between the recharge water entering the injection well and the heat reservoir, reducing the risk of silica precipitation, clay mineral hydration expansion and particle migration caused by sudden temperature change, and solving the problems of large chemical agent consumption, high risk of formation pollution and limited effect on siliceous scale in the related art, and the technical problem of high maintenance cost of physical law.

Description

Technical Field

[0001] This application relates to the intersection of geothermal energy development and utilization with renewable energy consumption, specifically to a geothermal reservoir anti-blocking and energy storage synergy system and control method. Background Technology

[0002] In geothermal resource development, reinjection technology is commonly used to re-inject geothermal tailwater into the reservoir to maintain pressure. However, during long-term reinjection, blockage has become a core bottleneck restricting the development of the geothermal industry. In the circulation path from the production well to the reinjection well, the temperature undergoes drastic changes (the high-temperature fluid drops significantly after surface heat exchange, and is then reinjected into the high-temperature reservoir as low-temperature tailwater). This rapid temperature drop and rise is the fundamental driving force triggering various chemical precipitation processes, altering fluid properties, and affecting microbial activity. Different types of geothermal reservoirs exhibit significant differences in mineral composition, pore scaling, and fluid chemical environment, leading to drastically different blockage mechanisms caused by temperature changes.

[0003] Sandstone geothermal reservoirs are primarily composed of quartz, feldspar, and clay cement (such as montmorillonite). During reinjection, the influx of low-temperature reinjection water into the high-temperature sandstone reservoir disturbs the original water-rock interaction environment, promoting the hydration and expansion of clay minerals such as montmorillonite, leading to pore channel shrinkage and decreased permeability. Simultaneously, the reinjection process easily triggers clay particle stripping and migration, which deposits in narrow pore areas. Low-temperature reinjection conditions further enhance this blocking effect. As reinjection continues, migrating particles may combine with carbonates, silica, and other precipitates to form complex blockages, further reducing reservoir permeability. Therefore, sandstone geothermal reservoir blockage is a physical-chemical coupling process involving clay expansion, particle migration, and mineral precipitation.

[0004] Granite (hot dry rock) geothermal reservoirs are mainly composed of quartz and feldspar. During reinjection, the low-temperature reinjection water enters the high-temperature reservoir, disturbing the original thermodynamic and geochemical equilibrium of the reservoir, reducing the stable dissolved state of silica in the fluid, and promoting its precipitation and formation of siliceous scale. As reinjection continues, silica deposits continuously adhere to the fracture walls and near-wellbore area, leading to narrowing of flow channels, increased reinjection resistance, and decreased reservoir accepting capacity. Therefore, siliceous scaling induced by low-temperature reinjection is an important cause of blockage in granite geothermal reservoirs and a major factor affecting the long-term stable operation of reinjection wells.

[0005] The aforementioned blockages mainly occur in the injection section and near-wellbore area of ​​the reinjection well. When low-temperature reinjection water enters a high-temperature reservoir, it easily alters the fluid chemical environment and water-rock interaction conditions in the near-wellbore area, promoting silica precipitation and adhesion to the wellbore wall and fracture surfaces. For sandstone reservoirs, low-temperature reinjection promotes the hydration and expansion of clay minerals, and the migration of particles generated during reinjection is more likely to cause pore channel blockage and a decrease in reservoir permeability under low-temperature conditions. As the blockage material accumulates, the reinjection pressure gradually increases, and the reservoir's accepting capacity continuously decreases.

[0006] In related technologies, chemical descaling or physical cleaning methods are mainly used for descaling. However, chemical methods have problems such as high consumption of reagents, high risk of formation contamination, and limited effectiveness against silica scale. Physical methods usually require well shutdown operations, resulting in high maintenance costs. Summary of the Invention

[0007] This application provides a geothermal reservoir anti-blocking and energy storage synergy system and control method, which can solve the problems in related technologies where chemical descaling methods are used to remove blockages generated by geothermal tailwater, resulting in high consumption of reagents, high risk of formation contamination, and limited effectiveness against silica scale; and physical methods usually require well shutdown operations, resulting in high maintenance costs.

[0008] In a first aspect, embodiments of this application provide a geothermal reservoir anti-blocking and energy storage synergy system, comprising: a green electricity supply unit; a thermal storage unit having an electric heating module, the electric heating module being electrically connected to the green electricity supply unit so that the green electricity supply unit supplies energy to the electric heating module, the electric heating module being used to heat the reinjection water in the thermal storage unit; and a reinjection unit connected to the thermal storage unit, the reinjection unit being used to transport the reinjection water output from the thermal storage unit to an injection well for reinjection.

[0009] In conjunction with the first aspect, in one embodiment, the geothermal reservoir anti-blocking and energy storage synergy system further includes: an energy management unit, which is electrically connected to the green energy supply unit and the electric heating module respectively. The energy management unit is used to obtain the power supply status of the green energy supply unit and control the operation of the electric heating module.

[0010] In conjunction with the first aspect, in one embodiment, the geothermal reservoir anti-blocking and energy storage synergy system further includes a reservoir type determination module, which is used to obtain the reservoir type of the target reservoir. The reservoir type determination module includes a data acquisition submodule, a lithology identification submodule, a reservoir database, and an identification result output submodule. The data acquisition submodule is used to acquire basic information about the target reservoir. The lithology identification submodule is used to analyze and process the acquired basic information and determine the reservoir type of the target reservoir based on geological data or fluid geochemical parameters. The reservoir database is used to store lithological characteristics, hydrochemical characteristic parameters, and recommended reinjection control parameters corresponding to different reservoir types. The identification result output submodule is signal-connected to the power management unit, and is used to send the target reservoir type to the power management unit. The power management unit is used to call the corresponding reinjection temperature parameters based on the reservoir type determination result of the target reservoir.

[0011] In conjunction with the first aspect, in one embodiment, the geothermal reservoir anti-blocking and energy storage coordination system further includes a temperature control unit: the temperature control unit includes multiple temperature sensors and a controller, the multiple temperature sensors are respectively installed at the outlet of the thermal storage unit and the inlet of the injection well, and the multiple temperature sensors are all signal-connected to the controller; the power management unit is signal-connected to the controller, and the controller is used to control the output power of the electric heating module according to the reinjection temperature parameters called by the power management unit and the temperatures obtained by the multiple temperature sensors.

[0012] In conjunction with the first aspect, in one embodiment, the data acquisition submodule includes multiple monitoring sensors. The multiple monitoring sensors are installed in the front-end sampling pipeline before the produced fluid from the production well enters the surface heat exchange system. The multiple monitoring sensors are used to collect characteristic parameters of the target thermal reservoir fluid and transmit them to the lithology identification submodule for thermal reservoir type identification. The characteristic parameters of the target thermal reservoir fluid include at least one of temperature, pressure, silica concentration, mineralization, turbidity, and flow rate.

[0013] In conjunction with the first aspect, in one embodiment, the thermal storage unit includes a reinjection water storage tank, an inlet pipe, and an outlet pipe. The inlet pipe is connected to the reinjection water storage tank, and the electric heating module is installed in the reinjection water storage tank so that the reinjection water storage tank is used to store high-temperature reinjection water. One end of the outlet pipe is connected to the reinjection water storage tank, and the other end is connected to the reinjection unit.

[0014] In conjunction with the first aspect, in one embodiment, an inlet valve is installed on the side of the inlet pipe near the reinjection water storage tank, and an outlet valve is installed on the side of the outlet pipe near the reinjection water storage tank. Both the inlet valve and the outlet valve are signal-connected to the power management unit. The power management unit is used to control the opening and closing of the inlet valve and the outlet valve according to the power supply status of the green electricity supply unit.

[0015] In conjunction with the first aspect, in one embodiment, the electric heating module includes a plurality of electric heating elements, all of which are installed within the heat storage unit; The power management unit is used to control the operation of some or all of the multiple electric heating elements according to the power supply of the green power supply unit.

[0016] Secondly, this application provides a control method for a geothermal reservoir anti-blocking and energy storage synergy system as described above. The control method includes: using surplus electricity from a green power supply unit to drive an electric heating module to heat the reinjection water in the thermal storage unit; controlling the start of a reinjection pump in the reinjection unit to output the reinjection water in the thermal storage unit to an injection well for reinjection.

[0017] In conjunction with the second aspect, in one embodiment, the geothermal reservoir anti-blocking and energy storage synergy system further includes an energy management unit. The method of using surplus electricity from the green energy supply unit to drive the electric heating module to heat the reinjection water in the thermal storage unit includes: acquiring the power supply status of the green energy supply unit; when the green energy supply unit provides sufficient power, controlling both the inlet valve of the inlet pipe and the outlet valve of the outlet pipe to open, and having the energy management unit control the electric heating module to operate continuously to heat the reinjection water in the reinjection water storage tank, so that the water temperature reaches or maintains the target reinjection temperature; when the green energy supply unit provides insufficient power, driving the inlet valve of the inlet pipe to close and the outlet valve of the outlet pipe to open, and having the energy management unit control the electric heating module to stop operating or reduce its output power, and using the high-temperature reinjection water already stored in the reinjection water storage tank to continue supplying water to the reinjection unit.

[0018] The beneficial effects of the technical solutions provided in this application include: By utilizing green electricity supply units to power the electric heating modules, the reinjection water in the thermal storage unit can reach a higher temperature before entering the injection well. This reduces the temperature difference between the reinjection water entering the injection well and the thermal storage, thereby reducing the risk of blockage caused by sudden temperature changes, such as silica precipitation, clay mineral hydration expansion, and particle migration. This solves the problems of high reagent consumption, high risk of formation contamination, and limited effectiveness against silica scale in related technologies using chemical descaling, as well as the high maintenance costs associated with physical methods. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram of the principle of the geothermal reservoir anti-blocking and energy storage synergy system provided in the embodiments of this application; Figure 2 This is another schematic diagram of the principle of the geothermal reservoir anti-blocking and energy storage synergy system provided in the embodiments of this application; Figure 3 A flowchart of the control method for a geothermal reservoir anti-blocking and energy storage synergistic system provided in the embodiments of this application. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0022] This application provides a geothermal reservoir anti-clogging and energy storage synergistic system, which solves the problems in related technologies where chemical descaling methods for removing blockages from geothermal tailwater have high reagent consumption, high risk of formation contamination, and limited effectiveness against siliceous scale; physical methods typically require well shutdown operations, resulting in high maintenance costs.

[0023] See Figure 1 The diagram illustrates a geothermal reservoir anti-blocking and energy storage synergy system provided in this application embodiment. It may include: a green electricity supply unit; a thermal storage unit, the thermal storage unit having an electric heating module electrically connected to the green electricity supply unit, enabling the green electricity supply unit to supply energy to the electric heating module, the electric heating module being used to heat the reinjection water within the thermal storage unit; and a reinjection unit connected to the thermal storage unit, the reinjection unit being used to transport the reinjection water output from the thermal storage unit to an injection well for reinjection. It should be understood that the green electricity source for the green electricity supply unit may include surplus electricity generated by wind power generation, photovoltaic power generation, and other renewable energy power generation systems. Preferably, the green electricity supply unit preferentially utilizes surplus electricity (including curtailed wind and solar power) generated by wind power generation and photovoltaic power generation to drive the electric heating module to heat the reinjection water, realizing the conversion of electrical energy into thermal energy in the reinjection water, and achieving underground thermal energy storage through high-temperature reinjection.

[0024] This application embodiment utilizes a green electricity supply unit to power the electric heating module, enabling the reinjection water in the thermal storage unit to reach a higher temperature before entering the injection well. This reduces the temperature difference between the reinjection water entering the injection well and the thermal storage, mitigating the risk of blockage caused by sudden temperature changes such as silica precipitation, clay mineral hydration expansion, and particle migration. It also solves the problems of high reagent consumption, high formation contamination risk, and limited effectiveness against silica scale associated with chemical descaling in related technologies; and the high maintenance costs associated with physical methods. In this application embodiment, the electric heating module can be an immersion electric heater, a shell-and-tube electric heater, or other electric heating devices, and can be installed inside the thermal storage unit. Its rated power is determined based on the reinjection flow rate, target reinjection temperature, and required reinjection water temperature rise, preferably 10-100kW.

[0025] In some optional embodiments, the geothermal reservoir anti-blocking and energy storage coordination system may further include: an energy management unit, which is electrically connected to both the green electricity supply unit and the electric heating module. The energy management unit is used to acquire the power supply status of the green electricity supply unit and control the operation of the electric heating module. It should be understood that the energy management unit can acquire the green electricity supply status in the green electricity supply unit in real time and control the operation of the electric heating module according to the green electricity supply capacity. In this embodiment, when the green electricity supply is sufficient, green electricity is preferentially used to heat the reinjection water, and excess electricity can be stored or connected to the grid for output; when the green electricity supply is insufficient, the energy management unit cooperates with the thermal storage unit to release the stored heat to maintain the stable operation of the reinjection system. It should be understood that the output end of the green electricity supply unit is connected to the electric heating module, and surplus green electricity such as wind and solar power is preferentially used to heat the reinjection water, realizing the conversion and storage of electrical energy into underground thermal energy; when the green electricity supply is sufficient, excess electricity can be stored or connected to the grid for output.

[0026] In some optional embodiments, the geothermal reservoir anti-blocking and energy storage synergy system further includes a reservoir type determination module, which is used to obtain the reservoir type of the target reservoir. This module includes a data acquisition submodule, a lithology identification submodule, a reservoir database, and an identification result output submodule. The data acquisition submodule is used to obtain basic information about the target reservoir. It should be understood that reservoir types typically include granite-type and sandstone-type reservoirs. The critical temperature for silica precipitation in granite-type reservoirs and the trigger temperature for clay mineral hydration expansion in sandstone-type reservoirs are different. Therefore, identifying the target reservoir type before reinjection and adjusting the reinjection water to a target reinjection temperature matching the reservoir type based on the identification results is crucial for reducing the risk of reservoir blockage and ensuring the long-term stable operation of the reinjection system.

[0027] Furthermore, the lithology identification submodule is used to analyze and process the acquired basic information and determine the reservoir type of the target reservoir based on geological data or fluid geochemical parameters. In this embodiment, the basic information may include manually input reservoir geological data, lithological descriptions, well logging data, and well logging data from the geothermal exploration database, as well as operating parameters such as fluid temperature, pressure, silica concentration, mineralization, turbidity, and flow rate collected in real time by monitoring sensors. Correspondingly, the basic information may be operating parameters such as fluid temperature, pressure, silica concentration, mineralization, turbidity, and flow rate collected in real time by monitoring sensors through the data acquisition submodule; or it may be parameters such as manually input reservoir geological data, lithological descriptions, well logging data, and well logging data directly obtained from geothermal exploration data.

[0028] Furthermore, the geothermal reservoir database is used to store lithological characteristics, hydrochemical characteristic parameters, and recommended reinjection control parameters corresponding to different geothermal reservoir types. Preferably, the geothermal reservoir database may include rock and mineral composition, fluid chemical characteristics, and operating parameter ranges corresponding to different lithological geothermal reservoirs. For granite-type geothermal reservoirs, the determination is primarily based on silica concentration, water temperature, and pressure variation characteristics; for sandstone-type geothermal reservoirs, the determination is primarily based on salinity, turbidity, and pressure variation characteristics. The determination results can serve as the basis for subsequent target reinjection temperature setting and anti-clogging control strategy adjustment.

[0029] Furthermore, the identification result output submodule is signal-connected to the power management unit. This submodule sends the target thermal storage type to the power management unit, which then calls the corresponding reinjection temperature parameters based on the thermal storage type determination result. In other words, the power management unit can call the corresponding reinjection control parameters based on the determination result obtained from the identification result output submodule. The typical temperature of granite-type thermal storage is 150-200℃, and its main blockage form is silica scale formed by silica precipitation. Therefore, based on the blockage characteristics of granite-type thermal storage, this application sets the target reinjection water temperature to 60%-80% of the thermal storage temperature (i.e., 90-120℃). The typical reservoir temperature of sandstone-type geothermal reservoirs is 40-80℃. The main blockage forms are pore blockage caused by clay expansion and particle migration. Therefore, based on the blockage characteristics of sandstone-type geothermal reservoirs, this application controls the target reinjection water temperature within a range close to the geothermal reservoir temperature, preferably 35℃-60℃, or controls the temperature difference between the reinjection water and the geothermal reservoir to not exceed 20℃.

[0030] See Figure 2As shown, in some optional embodiments, the geothermal reservoir anti-blocking and energy storage collaborative system may further include a temperature control unit: the temperature control unit includes multiple temperature sensors and a controller, the multiple temperature sensors are respectively installed at the outlet of the thermal storage unit and the inlet of the injection well, and the multiple temperature sensors are all signal-connected to the controller; the power management unit is signal-connected to the controller, and the controller is used to control the output power of the electric heating module according to the reinjection temperature parameters called by the power management unit and the temperature obtained by the multiple temperature sensors. In this embodiment, two temperature sensors are set, and the two temperature sensors are respectively installed at the outlet of the thermal storage unit and the inlet of the injection well, for real-time acquisition of reinjection water temperature, and sending the acquired temperature data to the controller. At this time, the controller is connected to the power management unit and the temperature sensors respectively, for receiving the target reinjection temperature control command sent by the power management unit, and combining it with the reinjection water temperature acquired in real time by the temperature sensors. Preferably, the controller can also be electrically connected to the electric heating module to perform closed-loop control of the electric heating module's output power after receiving the target reinjection temperature control command sent by the power management unit and combining it with the real-time reinjection water temperature collected by the temperature sensor. Preferably, the controller employs a PID control algorithm to dynamically adjust the output power of the electric heating module based on the temperature deviation between the target reinjection temperature and the real-time reinjection water temperature, ensuring the reinjection water temperature remains stable within ±2℃ of the target reinjection temperature. Specifically, when the target geothermal reservoir is identified as a granite-type geothermal reservoir, the temperature control unit calls the reinjection temperature control parameters corresponding to granite-type geothermal reservoirs to heat the reinjection water and control it to reach the set temperature, thereby reducing the risk of silica scaling; when the target geothermal reservoir is identified as a sandstone-type geothermal reservoir, the temperature control unit calls the reinjection temperature control parameters corresponding to sandstone-type geothermal reservoirs to maintain the reinjection water temperature within a suitable range, thereby reducing the risk of clay mineral expansion and particle blockage. This application embodiment, through the above-mentioned determination of geothermal reservoir type and differentiated reinjection control method, can select the corresponding reinjection temperature control strategy according to the blockage characteristics of geothermal reservoirs of different lithologies, realize the coordinated operation of geothermal reservoir anti-blockage and green energy storage processes, and improve the long-term stability of geothermal reinjection system.

[0031] In some optional embodiments, the data acquisition submodule may include multiple monitoring sensors installed in the front-end sampling pipeline before the produced fluid from the production well enters the surface heat exchange system. These sensors collect characteristic parameters of the target geothermal reservoir fluid and transmit them to the lithology identification submodule for geothermal reservoir type identification. The characteristic parameters of the target geothermal reservoir fluid include at least one of temperature, pressure, silica concentration, salinity, turbidity, and flow rate. In this embodiment, the multiple monitoring sensors may include a pressure sensor, a silica concentration sensor, a salinity sensor, and a turbidity sensor, respectively. Preferably, each monitoring sensor is installed in the front-end sampling pipeline before the produced fluid enters the heat exchange system, so that the collected parameters can accurately reflect the pressure state and hydrochemical characteristics of the original fluid in the target geothermal reservoir, avoiding changes in the physical properties of the produced fluid after surface heat exchange, cooling, desanding, or transportation treatment, which could affect the accuracy of the geothermal reservoir type identification results. It should be understood that after the data acquisition submodule obtains the various parameters, it can transmit these parameters to the lithology identification submodule. The lithology identification submodule, combined with typical characteristic parameters from the existing geothermal reservoir database, comprehensively analyzes the operating parameters collected by the monitoring sensors, such as reinjection fluid temperature, pressure, silica concentration, mineralization, and turbidity, and determines the target geothermal reservoir type through parameter feature matching. Preferably, the lithology identification submodule can directly determine whether the target geothermal reservoir belongs to a granite-type or sandstone-type geothermal reservoir based on geothermal exploration data. However, when lithology data is unavailable, the data acquisition submodule can be used to obtain the parameters from the original fluid.

[0032] Preferably, multiple monitoring sensors can be installed at the inlet of the injection well. These sensors may include at least one of a pressure sensor, a silica concentration sensor, a mineralization sensor, and a turbidity sensor. Each monitoring sensor is signal-connected to a data acquisition submodule, which is communicatively connected to a power management unit. The operating parameters collected by each monitoring sensor are transmitted to the power management unit in real time via the data acquisition submodule. The power management unit combines the reservoir type identification result output by the reservoir type determination module with at least one of the operating parameters collected by each monitoring sensor, including temperature, pressure, flow rate, silica concentration, mineralization, and turbidity, to comprehensively assess the blockage risk of the target reservoir. Specifically, when the target reservoir is a granite-type reservoir, the power management unit assesses the risk of silica scaling based on changes in silica concentration, temperature, and pressure; when the target reservoir is a sandstone-type reservoir, the power management unit assesses the risk of particulate blockage based on changes in mineralization, turbidity, pressure, and flow rate. Based on the blockage risk assessment results, the power management unit determines or corrects the target reinjection temperature within the preset reinjection temperature range corresponding to the thermal storage type, and sends the corrected target reinjection temperature to the controller of the temperature control unit; the controller adjusts the output power of the electric heating module according to the deviation between the corrected target reinjection temperature and the real-time reinjection water temperature.

[0033] In some optional embodiments, the thermal storage unit may include a reinjection water storage tank, an inlet pipe, and an outlet pipe. The inlet pipe is connected to the reinjection water storage tank, and the electric heating module is installed in the reinjection water storage tank, enabling the reinjection water storage tank to store high-temperature reinjection water. One end of the outlet pipe is connected to the reinjection water storage tank, and the other end is connected to the reinjection unit. It should be understood that the reinjection water storage tank is used to store reinjection water heated by the electric heating module, and to achieve thermal energy storage and stable supply. In this embodiment, the electric heating module is installed inside the reinjection water storage tank to heat the reinjection water inside the tank; in some other embodiments, the electric heating module may also be installed on the inlet pipe connected to the reinjection water storage tank to heat the reinjection water entering the tank. Preferably, the reinjection water storage tank is an insulated water storage tank, the tank body includes a stainless steel inner liner, a polyurethane insulation layer and a stainless steel outer shell, and the tank volume is designed for 4-8 hours of reinjection water storage to meet the continuous reinjection needs under green power fluctuation conditions.

[0034] Preferably, the thermal storage unit is connected to an electric heating module, a temperature control unit, an energy management unit, and a reinjection unit. The electric heating module heats the reinjection water to the target reinjection temperature before delivering it to the thermal storage unit; the temperature control unit monitors the reinjection water temperature at the outlet of the thermal storage unit in real time; the energy management unit controls the thermal storage and heating process of the thermal storage unit according to the green electricity supply status, thermal storage status, and reinjection demand; and the reinjection unit delivers the reinjection water output from the thermal storage unit to the injection well for reinjection.

[0035] In some optional embodiments, an inlet valve is installed on the side of the inlet pipe near the reinjection water storage tank, and an outlet valve is installed on the side of the outlet pipe near the reinjection water storage tank. Both the inlet and outlet valves are signal-connected to the power management unit, which controls the opening and closing of the inlet and outlet valves according to the power supply status of the green energy supply unit. That is, an inlet valve is provided on the inlet pipe, and an outlet valve is provided on the outlet pipe; both the inlet and outlet valves are signal-connected to the power management unit, which controls the opening and closing of the inlet and outlet valves according to the power supply status of the green energy supply unit.

[0036] In some optional embodiments, the electric heating module includes multiple electric heating elements, all of which are installed within the thermal storage unit. The power management unit controls the operation of some or all of the multiple electric heating elements based on the power supply of the green energy supply unit. In this embodiment, each electric heating element is an independent heating module, and each heating module can be started and stopped independently or operated in combination to adapt to the fluctuating characteristics of green energy supply such as wind power and photovoltaic power generation. The power management unit controls the activation of the appropriate number of heating modules based on the green energy supply status, the thermal storage status of the thermal storage unit, and the reinjection requirements. It also adjusts the output power of the electric heating modules in real time through a temperature control unit to stabilize the reinjection water temperature within the target reinjection temperature range.

[0037] See Figure 3 As shown in the embodiments of this application, a control method for using the geothermal reservoir anti-blocking and energy storage synergistic system as described above is also provided. The control method may include: S1: The surplus electricity from the green energy supply unit drives the electric heating module to heat the reinjection water in the thermal storage unit. When the electricity generated by the wind power or photovoltaic power generation system exceeds the grid's absorption capacity, the power management unit transmits the surplus electricity to the electric heating module, which then heats the reinjection water in the thermal storage unit. The electric heating module converts electrical energy into heat energy, gradually increasing the temperature of the reinjection water in the thermal storage unit until it reaches the target reinjection temperature for the corresponding thermal storage type. Through this method, surplus green electricity that might otherwise be wasted is converted into heat energy and stored in the reinjection water within the thermal storage unit, achieving the conversion of electrical energy into heat energy and the effective utilization of green electricity.

[0038] S2: The reinjection pump in the reinjection unit is started to output the reinjection water from the thermal storage unit to the injection well for reinjection. In this embodiment, the reinjection unit may include a reinjection pump, a main reinjection pipeline, and an injection well, used to transport and inject the reinjection water heated by the electric heating module into the target thermal storage. The reinjection pump provides the power to transport the reinjection water, delivering the reinjection water output from the thermal storage unit to the injection well; the injection well injects the heated reinjection water into the target thermal storage, realizing thermal energy reinjection and underground thermal storage. The reinjection unit can also be connected to an energy management unit and a temperature control unit. Based on the control parameters issued by the energy management unit and the target reinjection temperature set by the temperature control unit, the unit heats the reinjection water for reinjection, maintaining the reinjection water temperature within the target reinjection temperature range for the corresponding thermal storage type.

[0039] In some optional embodiments, the geothermal reservoir anti-blocking and energy storage synergy system further includes an energy management unit, wherein the use of surplus electricity from the green electricity supply unit to drive the electric heating module to heat the reinjection water in the thermal storage unit includes: S11: Obtain the power supply status of the green energy supply unit.

[0040] S12: When the green energy supply unit provides sufficient power, both the inlet valve of the inlet pipe and the outlet valve of the outlet pipe are opened. The power management unit controls the electric heating module to operate continuously, heating the reinjected water in the reinjection water storage tank to reach or maintain the target reinjection temperature. In other words, when the green energy supply unit provides sufficient power, water from the inlet pipe can continuously enter the reinjection water storage tank. The power management unit controls the electric heating module to operate continuously, ensuring the reinjected water in the storage tank remains within the rated temperature range before entering the reinjection unit. During this process, the electric heating module automatically adjusts its output power based on real-time changes in the water temperature in the storage tank to maintain a stable water temperature, avoiding overheating or insufficient temperature, thereby achieving a continuous and stable conversion and supply of surplus green electricity into heat energy.

[0041] S13: When the green electricity supply unit is insufficient, the inlet valve of the inlet pipeline is closed and the outlet valve of the outlet pipeline is opened. The power management unit then controls the electric heating module to stop operating or reduce its output power, utilizing the high-temperature reinjection water stored in the reinjection water tank to continue supplying water to the reinjection unit. Specifically, because the output power of the green electricity supply unit cannot meet the normal operating requirements of the electric heating module, the power management unit controls the inlet valve to close, stopping the replenishment of reinjection water to the reinjection water tank. Simultaneously, it controls the electric heating module to stop operating or switch to a low-power state. At the same time, the outlet valve on the outlet pipeline remains open, and the pre-stored high-temperature reinjection water in the reinjection water tank is output to the reinjection unit via the outlet pipeline, and then transported by the reinjection pump to the injection well for continued reinjection. Through this control method, even under conditions of insufficient green electricity supply, the system can still rely on the heat energy stored in the reinjection water tank to maintain a stable target reinjection water temperature, ensuring continuous operation of the reinjection process and realizing cross-period utilization of heat energy.

[0042] Preferably, before using surplus electricity from the green energy supply unit to drive the electric heating module to heat the reinjection water in the thermal storage unit, the rock type of the target thermal storage unit can be determined by a thermal storage type determination module; then, based on the thermal storage type identification result output by the thermal storage type determination module, the corresponding target reinjection water temperature is determined. Specifically: when the thermal storage type is granite-type, the reinjection water temperature is controlled at 60%-80% of the thermal storage temperature (90-120℃ recommended) to reduce the reinjection temperature difference and inhibit silica precipitation; when the thermal storage type is sandstone-type, the target reinjection water temperature is controlled to be maintained within the preset temperature range corresponding to the thermal storage type (35-60℃ recommended) to reduce clay mineral expansion and particle migration.

[0043] In this embodiment, the target reinjection temperature is determined according to the target geothermal reservoir type. By reducing the temperature difference between the reinjection water and the geothermal reservoir, the risk of silica precipitation and scaling in granite-type geothermal reservoirs and the risk of blockage caused by clay mineral expansion and particle migration in sandstone-type geothermal reservoirs are reduced, thus improving the blockage problem in the reinjection process from the source. Furthermore, surplus electricity from renewable energy sources such as wind and solar power is used to heat the reinjection water, and combined with the thermal storage unit to achieve thermal energy storage. This meets the reinjection demand while improving the utilization rate of green electricity, achieving coordinated operation of green electricity supply and geothermal reinjection. Additionally, by combining the geothermal reservoir type determination module, monitoring sensor group, and power management unit, the target reinjection temperature is determined according to different geothermal reservoir types and real-time operating parameters, and the reinjection operating parameters are dynamically adjusted to achieve differentiated anti-blockage control for granite-type and sandstone-type geothermal reservoirs, improving the adaptability of system operation. Moreover, high-temperature reinjection is used to supplement the underground geothermal reservoir with thermal energy, slowing down the temperature decay of the reservoir and improving the underground thermal energy storage capacity, providing support for the sustainable development and utilization of geothermal resources. This application mainly achieves geothermal reservoir anti-clogging through reinjection temperature control, which eliminates or reduces the need for chemical scale inhibitors, thus reducing the impact on underground geothermal reservoirs and the geological environment and improving the environmental friendliness of the geothermal reinjection process.

[0044] In some optional embodiments, taking a granite-type geothermal reservoir as an example: the reservoir temperature is approximately 180°C, and the original reinjection water temperature is 30°C. During long-term operation, due to the large temperature difference between the reinjection water and the geothermal reservoir, silica precipitation and silica scale formation occur in the injection section of the reinjection well and the near-wellbore fracture area, leading to a gradual increase in reinjection pressure and a decrease in the reservoir's accepting capacity.

[0045] Correspondingly, the geothermal reservoir anti-blocking and energy storage synergy system configuration includes a 50kW photovoltaic power generation system, a 40kW electric heating module, and a 20m³ / h electric heating system. 3 The system comprises an insulated storage tank, an energy management unit, a thermal storage type determination module, a monitoring sensor group, and a reinjection unit. The thermal storage type determination module identifies the target thermal storage as granite-type. The energy management unit then calls the corresponding granite-type reinjection control parameters, and the temperature control unit sets the target reinjection water temperature to 110℃. During system operation, when the photovoltaic power generation system provides sufficient power, the green energy supply unit prioritizes supplying power to the electric heating module to heat the reinjection water, storing the water at the target temperature in the thermal storage unit. When photovoltaic output decreases or there is no sunlight at night, the system prioritizes using the hot water stored in the thermal storage unit for continuous reinjection.

[0046] Taking a sandstone-type geothermal reservoir as an example: The target geothermal reservoir is a sandstone-type geothermal reservoir with a reservoir temperature of 45℃ and an original reinjection water temperature of about 15℃. During long-term operation, due to the presence of a high proportion of clay minerals in the near-wellbore area, clay mineral hydration and expansion and particle migration occur during reinjection, resulting in a continuous increase in reinjection pressure and a gradual decrease in the reservoir's accepting capacity.

[0047] Correspondingly, the geothermal reservoir anti-blocking and energy storage synergy system configuration includes a 30kW photovoltaic array, a 20kW electric heater, and a 15m... 3 The system includes a thermal storage unit, an electrical management unit, a thermal storage type determination module, a monitoring sensor group, and a reinjection unit. The thermal storage type determination module identifies the target thermal storage as a sandstone-type thermal storage. The electrical management unit calls the corresponding sandstone-type reinjection control parameters, and the temperature control unit sets the target reinjection water temperature to 45℃.

[0048] During system operation: When the photovoltaic power generation system provides sufficient power, the green electricity supply unit drives the electric heating module to heat the reinjection water and stores the reinjection water that has reached the target temperature in the thermal storage unit; when the green electricity supply decreases or there is no sunlight at night, the system prioritizes using the hot water in the thermal storage unit to maintain reinjection operation.

[0049] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0050] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0051] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A geothermal reservoir anti-blocking and energy storage synergistic system, characterized in that, It includes: Green electricity supply unit; A thermal storage unit, wherein the thermal storage unit has an electric heating module, the electric heating module is electrically connected to the green electricity supply unit, so that the green electricity supply unit supplies power to the electric heating module, and the electric heating module is used to heat the reinjected water in the thermal storage unit; A reinjection unit is connected to the thermal storage unit and is used to transport the reinjection water output from the thermal storage unit to the injection well for reinjection.

2. The geothermal reservoir anti-blocking and energy storage synergistic system as described in claim 1, characterized in that, The geothermal reservoir anti-blocking and energy storage synergy system also includes: The power management unit is electrically connected to both the green energy supply unit and the electric heating module. The power management unit is used to obtain the power supply status of the green energy supply unit and control the operation of the electric heating module.

3. The geothermal reservoir anti-blocking and energy storage synergistic system as described in claim 2, characterized in that: The geothermal reservoir anti-blocking and energy storage coordination system also includes a thermal reservoir type determination module, which is used to obtain the thermal reservoir type of the target thermal reservoir. The reservoir type determination module includes a data acquisition submodule, a lithology identification submodule, a reservoir database, and an identification result output submodule. The data acquisition submodule is used to obtain basic information about the target reservoir. The lithology identification submodule is used to analyze and process the acquired basic information and determine the reservoir type of the target reservoir based on geological data or fluid geochemical parameters. The thermal reservoir database is used to store lithological characteristics, hydrochemical characteristic parameters, and recommended reinjection control parameters corresponding to different thermal reservoir types. The identification result output submodule is signal-connected to the power management unit. The identification result output submodule is used to send the target thermal storage type to the power management unit. The power management unit is used to call the corresponding reinjection temperature parameters according to the thermal storage type determination result of the target thermal storage.

4. The geothermal reservoir anti-blocking and energy storage synergistic system as described in claim 3, characterized in that, The geothermal reservoir anti-blockage and energy storage synergy system also includes a temperature control unit: The temperature control unit includes multiple temperature sensors and a controller. The multiple temperature sensors are respectively installed at the outlet of the thermal storage unit and the inlet of the injection well, and the multiple temperature sensors are all connected to the controller. The power management unit is signal-connected to the controller, and the controller is used to control the output power of the electric heating module according to the reinjection temperature parameters called by the power management unit and the temperature obtained by the multiple temperature sensors.

5. The geothermal reservoir anti-blocking and energy storage synergistic system as described in claim 3, characterized in that: The data acquisition submodule includes multiple monitoring sensors, which are installed in the front-end sampling pipeline before the produced fluid from the production well enters the surface heat exchange system. The multiple monitoring sensors are used to collect characteristic parameters of the target thermal reservoir fluid and transmit them to the lithology identification submodule for thermal reservoir type identification. The characteristic parameters of the target thermal reservoir fluid include at least one of temperature, pressure, silica concentration, mineralization, turbidity, and flow rate.

6. The geothermal reservoir anti-blocking and energy storage synergistic system as described in claim 2, characterized in that: The thermal storage unit includes a reinjection water storage tank, an inlet pipe and an outlet pipe. The inlet pipe is connected to the reinjection water storage tank, and the electric heating module is installed in the reinjection water storage tank so that the reinjection water storage tank can be used to store high-temperature reinjection water. One end of the outlet pipeline is connected to the reinjection water storage tank, and the other end is connected to the reinjection unit.

7. The geothermal reservoir anti-blocking and energy storage synergistic system as described in claim 6, characterized in that: An inlet valve is installed on the side of the inlet pipe near the reinjection water storage tank, and an outlet valve is installed on the side of the outlet pipe near the reinjection water storage tank. Both the inlet valve and the outlet valve are connected to the power management unit via signal. The power management unit is used to control the opening and closing of the inlet valve and the outlet valve according to the power supply status of the green electricity supply unit.

8. The geothermal reservoir anti-blocking and energy storage synergistic system as described in claim 2, characterized in that: The electric heating module includes multiple electric heating elements, all of which are installed inside the heat storage unit; The power management unit is used to control the operation of some or all of the multiple electric heating elements according to the power supply of the green power supply unit.

9. A control method utilizing the geothermal reservoir anti-blocking and energy storage synergistic system as described in any one of claims 1 to 8, characterized in that, The control method includes: The surplus electricity from the green energy supply unit is used to drive the electric heating module to heat the reinjected water in the thermal storage unit; The reinjection pump in the control reinjection unit is started, and the reinjection water in the thermal storage unit is output to the injection well for reinjection.

10. The control method as described in claim 9, characterized in that, The geothermal reservoir anti-blocking and energy storage synergy system also includes an energy management unit. The system utilizes surplus electricity from the green electricity supply unit to drive an electric heating module to heat the reinjected water within the thermal storage unit, including: Obtain the power supply status of the green energy supply unit; When the green energy supply unit provides sufficient power, the inlet valve of the water inlet pipeline and the outlet valve of the water outlet pipeline are both opened, and the power management unit controls the electric heating module to run continuously to heat the reinjection water in the reinjection water storage tank so that the water temperature reaches or maintains the target reinjection temperature. When the green energy supply unit is insufficient, the inlet valve of the inlet water pipeline is closed and the outlet valve of the outlet water pipeline is opened. The power management unit controls the electric heating module to stop operating or reduce its output power, and uses the high-temperature reinjection water stored in the reinjection water storage tank to continue to supply water to the reinjection unit.

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