Hydrothermal type geothermal heat reservoir protection method and system

Abstract

The invention relates to a hydrothermal type geothermal heat reservoir protection method and system, and provides a technical scheme of taking heat without taking water aiming at the problems of heat reservoir pressure unbalance, ground subsidence and pollution caused by traditional water taking type development. The system comprises a thermal reservoir parameter monitoring module which collects temperature, pressure and working medium states in real time; the double-path regulation and control module is divided into a first control path and a second control path; the execution module executes two types of signals through interlaced time sequences and controls the rotating speed of the circulating pump and the working medium flow. The core of the method is time domain decoupling: the pump speed is immediately reduced when the temperature exceeds a threshold value, and the flow is adjusted after the pressure abnormity is delayed for 10-30 seconds, so that the pressure and the temperature fluctuation are separated on a time axis. The delay duration is dynamically calculated to be 1.2-1.5 times of the thermal recovery period of the thermal reservoir, and self-adaptive adjustment is performed in combination with the rock heat capacity characteristic and the fracture development state.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of geothermal resource development and utilization, in particular to a hydrothermal geothermal reservoir protection method and system based on heat extraction without water extraction technology, which realizes efficient utilization of geothermal resources while effectively protecting the heat reservoir and maintaining its sustainability through innovative technical means. BACKGROUND

[0002] As a clean and renewable energy source, hydrothermal geothermal resources play an increasingly important role in the global energy structure. The main utilization method is to extract hot water or steam from the heat reservoir and convert the heat energy contained therein into electricity, heating and other forms of energy. However, in the traditional development process of geothermal resources, the water extraction development method is commonly used, which means that hot water is extracted from the heat reservoir and after heat energy utilization, the cooled water is directly discharged or recharged to the underground.

[0003] This water extraction development method has many drawbacks. First, the large-scale extraction of water from the heat reservoir will cause the heat reservoir pressure to drop, which will in turn cause ground subsidence, posing a serious threat to the surrounding geological environment and building safety. Second, during the recharging process, if the water quality of the recharged water does not meet the requirements of the heat reservoir, it may contaminate the heat reservoir and affect the sustainable use of geothermal resources. In addition, with the continuous expansion of the scale of geothermal resource development, the water consumption of water extraction development is also increasing, and this problem is particularly prominent in water scarce areas.

[0004] In order to solve the above problems, researchers have been exploring new geothermal resource development technologies. In recent years, the heat extraction without water extraction technology has gradually become a research hotspot, which aims to extract heat energy effectively without extracting water from the heat reservoir, thereby avoiding damage to the heat reservoir. However, the existing heat extraction without water extraction technology still has some shortcomings, such as low heat energy extraction efficiency, poor system stability, high cost, etc., which cannot meet the needs of large-scale commercial development. Therefore, there is an urgent need for an efficient, stable and cost-effective hydrothermal geothermal reservoir protection method and system to promote the sustainable development and utilization of geothermal resources. SUMMARY

[0005] The purpose of the present application is to provide a hydrothermal geothermal reservoir protection method and system, which effectively protects the heat reservoir through the heat extraction without water extraction technology, avoids ground subsidence, heat reservoir pollution and other problems, and at the same time improves the heat energy extraction efficiency, reduces the development cost, and realizes the efficient and sustainable utilization of geothermal resources.

[0006] The present application aims to provide a hydrothermal geothermal reservoir protection system, which comprises: a heat reservoir parameter monitoring module for real-time acquisition of heat reservoir temperature, pressure and circulating working medium state parameters; a double-path regulation module comprising: a first control path directly responding to the monitoring data and generating a primary regulation signal; a second control path parallel to the first control path and configured with a delay unit for generating a delayed secondary regulation signal; an execution module receiving the primary regulation signal and the secondary regulation signal and controlling the circulating pump speed and the working medium flow rate respectively through staggered execution timing, so as to decouple the abnormal fluctuation of the thermal reservoir parameters in the time domain.

[0007] Further, the delay duration of the delay unit is set to 10-30 seconds, which enables the thermal reservoir to recover from the disturbance caused by the primary regulation signal before the secondary regulation signal is triggered.

[0008] Further, the first control path comprises: a data conversion unit converting the temperature monitoring signal into a complementary temperature control signal pair; the temperature control signal pair directly driving the circulating pump frequency converter; the second control path comprises: a delay processing unit delaying the pressure monitoring signal to generate a complementary delayed pressure control signal pair; the delayed pressure control signal pair driving the working medium flow rate regulation valve.

[0009] Further, the double-path regulation module is arranged in a data analysis and processing center, wherein: the first control path is configured with a non-delayed real-time response channel; the second control path is configured with a programmable delay chip, and the delay duration is dynamically adjusted according to the rock heat capacity characteristics of the thermal reservoir.

[0010] The application also provides a hydrothermal geothermal reservoir protection method, comprising the following steps: receiving the thermal reservoir monitoring data through the parallel first control path and second control path; generating an immediate regulation instruction in the first control path; generating a delayed regulation instruction after injecting controllable delay in the second control path; staggered execution of the immediate regulation instruction and the delayed regulation instruction to decouple the pressure fluctuation and the temperature fluctuation of the thermal reservoir in the time domain.

[0011] Further, the delay duration is set to 1.2-1.5 times of the thermal recovery period of the thermal reservoir, which is determined by the following steps: measuring the rock thermal conductivity coefficient of the thermal reservoir; calculating the diffusion duration of the thermal disturbance in the rock; superimposing the fluid convection delay coefficient.

[0012] Further, when generating immediate adjustment instructions: When the temperature exceeds the threshold, immediately reduce the circulating pump speed; When generating delayed adjustment instructions: Reduce the working fluid flow after a delay of 10-30 seconds; Time interleaving of adjustment actions is formed.

[0013] Further, it also includes: Real-time transmission of monitoring data through 5G communication; Generating complementary control signal pairs in the data analysis center, including: The first group of signals drives the heat exchanger power adjustment; The second group of signals generated by the delay drives the back pressure valve opening.

[0014] Further, the second control path contains multiple levels of signal processing: First level: digital conversion of pressure data; Second level: inject programmable time delay; Third level: generate working fluid flow control waveform.

[0015] The application has active decoupling control of thermal reservoir parameter fluctuations. Specifically, it uses dual-path independent regulation, the first path (temperature → pump speed) responds in real time, and the second path (pressure → flow) injects a 10-30 second programmable delay. The interleaved execution timing includes primary signals (pump speed adjustment) and secondary signals (flow adjustment) triggered at different times to avoid adjustment action superposition. Compared with traditional geothermal systems where temperature and pressure fluctuations are physically coupled and amplified, leading to thermal reservoir instability, the application separates the two types of fluctuation responses in the time domain: when the temperature suddenly changes (such as exceeding the threshold), the pump speed is immediately reduced to reduce heat extraction; while pressure fluctuations (such as injection-production imbalance) trigger flow adjustment after rock thermal disturbance diffusion (about 10-30 seconds). The delay duration is dynamically calculated by a formula to ensure that the thermal reservoir returns to stability after the primary disturbance (pump speed change) and then responds to the secondary disturbance (flow change).

[0016] The application adopts complementary signal pair driving for precise execution. Specifically, the first path: temperature signal→analog-to-digital conversion (response <0.1 second)→generating a complementary rotating speed control signal pair→driving a frequency converter, pump speed adjustment range ±5%. The second path: pressure signal→digital filtering (cutoff frequency 0.1 Hz)→programmable delay (FPGA implementation)→generating a PWM flow control waveform, valve adjustment range ±15%. The complementary signal pair design (such as the temperature control signal pair and the delayed pressure control signal pair) solves the problem of insufficient accuracy of single signal control. Taking the temperature path as an example: the complementary signal pair can simultaneously output forward / reverse driving current to the circulating pump frequency converter, realizing millisecond-level fine adjustment (±5%) of rotating speed, and avoiding water hammer effect induced by pump speed step change. The pressure path is filtered by low-pass filtering (0.1 Hz cutoff) to filter out high-frequency noise, and then injected with precise delay by FPGA, and finally outputs a PWM waveform to smoothly adjust the valve, with a flow rate change rate limited to 3% / second.

[0017] The application has fault tolerance enhancement capability of a dual-path parallel architecture. The first path is a real-time channel without delay, and the second path is configured with a programmable delay chip. The two paths independently run in the data analysis center, and either path can take over the basic regulation in case of any failure. Traditional serial control links are prone to system crash due to single-point failure (such as sensor failure). The system adopts a parallel architecture, and the dual paths are decoupled in hardware and logic: the first path ensures the determinacy of temperature emergency response (such as reducing pump speed within 0.5 seconds when the temperature is too high), and the second path focuses on pressure stability. If the delay chip fails, the system can switch to a fixed delay mode (default 20 seconds); if the real-time channel is interrupted, the pressure path can still maintain flow control independently. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The figure is a schematic diagram of the framework of the application; Figure 2 The figure is a flowchart of the method of the application. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0020] Reference Figure 1 and Figure 2The application aims to provide a hydrothermal geothermal reservoir protection system, comprising: a reservoir parameter monitoring module for real-time collection of reservoir temperature, pressure and circulating working medium state parameters; a dual-path regulation module, comprising: a first control path for direct response to monitoring data and generation of a primary regulation signal; a second control path connected in parallel to the first control path and configured with a delay unit for generation of a delayed secondary regulation signal; and an execution module for receiving the primary and secondary regulation signals and controlling circulating pump speed and working medium flow rate through staggered execution timing, so as to decouple abnormal fluctuations of reservoir parameters in the time domain.

[0021] In the above embodiment, the real-time collection of temperature / pressure sensors and working medium flow meters is realized by the reservoir parameter monitoring module to form a closed-loop control input source. The dual-path regulation module is adopted: the first path (without delay): temperature signal→straight-through→pump speed instruction (fast temperature suppression). The second path (with delay): pressure signal→delay unit→flow rate instruction (pressure variation lagging). The execution module staggered timing: pump speed regulation (e.g. t=0 seconds start) and flow rate regulation (e.g. t=20 seconds start) staggered execution to avoid parameter resonance.

[0022] In the above embodiment, the application realizes the time domain decoupling of abnormal fluctuations of reservoir parameters through the three-level architecture of "reservoir parameter monitoring-dual-path regulation-execution module", and the core is "dual-path parallel regulation + staggered timing execution".

[0023] In the above embodiment, the reservoir parameter monitoring module as the "perception end" of data, real-time collection of reservoir temperature, pressure and circulating working medium (e.g. heat conducting fluid) state parameters (flow rate, temperature, etc.). Its role is to provide real-time data basis for regulation to avoid the problem of "parameter collection lag leading to regulation error" in traditional development. For example, the temperature monitoring accuracy can reach ±0.5℃, and the pressure monitoring resolution can reach 0.01MPa, ensuring that abnormal signals (e.g. temperature sudden rise, pressure sudden drop) are captured in time.

[0024] The dual-path regulation module is the "decision core" of the application, which realizes differentiated response by adopting a parallel architecture: the first control path is a "real-time channel without delay", which directly converts the monitoring data into a primary regulation signal (such as a pump speed reduction instruction when the temperature exceeds the threshold), ensuring a rapid response to emergency parameter abnormalities (such as a sudden temperature rise that may cause the thermal reservoir to overheat); the second control path is a "delayed regulation channel", which generates a secondary regulation signal by delaying the monitoring data (mainly the pressure signal) through a delay unit, avoiding the superposition of the regulation actions of the primary and secondary signals. The execution module, as the "execution end", receives the two levels of signals and controls the circulating pump speed (affecting the heat extraction intensity) and the working fluid flow (affecting the thermal reservoir fluid balance) through staggered timing. For example, when the temperature exceeds the threshold, the execution module first responds to the primary signal to reduce the pump speed, and then responds to the secondary signal to adjust the flow after 10-30 seconds, so that the temperature fluctuation and the pressure fluctuation are separated in the time axis (i.e. "time domain decoupling"), avoiding parameter resonance caused by mutual interference (such as the superposition of pressure drop and temperature rise in traditional development, which causes the destruction of the thermal reservoir structure).

[0025] In some embodiments, the delay duration of the delay unit is set to 10-30 seconds, which allows the thermal reservoir to recover from the disturbance caused by the primary regulation signal before the secondary regulation signal is triggered.

[0026] In the above embodiments, the core role of the delay duration is to buffer the disturbance impact of the primary regulation. The primary regulation signal (such as pump speed reduction) will temporarily change the heat flow distribution of the thermal reservoir, which may cause a small pressure fluctuation; if the secondary signal (such as flow adjustment) immediately follows, it will superimpose the disturbance, causing parameter fluctuation amplification. The 10-30 second delay provides a "self-recovery window" for the thermal reservoir - according to the thermal capacity characteristics of the thermal reservoir rock (the ability of the rock to absorb / release heat), this duration is sufficient for the thermal reservoir to recover from the primary disturbance to a relatively stable state. For example: when the temperature exceeds the threshold, the first path instruction reduces the pump speed, at which time the thermal reservoir's temperature begins to fall due to the decrease in heat extraction intensity, but may be accompanied by a temporary pressure rise; after 10-30 seconds, when the pressure fluctuation naturally subsides, the second path instructs to adjust the flow, avoiding secondary pressure fluctuation.

[0027] Based on the thermal inertia of the thermal reservoir (slow rock heat conduction, time required for thermal recovery), the delay design provides a self-regulation space for the thermal reservoir, ensuring the "non-superposition" of the two-level regulation actions and reducing the parameter fluctuation amplitude.

[0028] In some embodiments, the first control path includes a data conversion unit that converts the temperature monitoring signal into a complementary pair of temperature control signals; the pair of temperature control signals directly drives the circulating pump frequency converter. The second control path includes a delay processing unit that delays the pressure monitoring signal to generate a complementary pair of delayed pressure control signals; the pair of delayed pressure control signals drives the working fluid flow regulating valve.

[0029] In the above embodiment, the first path focuses on temperature-pump speed regulation, and the variable frequency driver is driven by a complementary signal pair; the second path focuses on pressure-flow rate regulation, and the flow rate valve is driven by a delayed complementary signal pair, to achieve precise regulation.

[0030] Signal processing of the first control path: the data conversion unit converts the temperature monitoring signal into a “complementary temperature control signal pair” (such as a forward driving current and a reverse driving current), which directly drives the circulating pump variable frequency driver. The advantage of the “complementary signal pair” is to avoid the insufficient accuracy of single signal regulation: for example, when the temperature is slightly higher than the threshold, the forward signal drives the variable frequency driver to reduce the speed slightly (such as by 5%); when the temperature is much higher than the threshold, the reverse signal superimposes to increase the speed reduction amplitude (such as by 10%), to achieve “stepwise precise regulation” and avoid water hammer effect caused by sudden pump speed change (traditional single signal may cause sudden pump speed change, impacting the fracture structure of the thermal reservoir).

[0031] Signal processing of the second control path: the delay processing unit delays the pressure monitoring signal for 10-30 seconds to generate a “complementary delayed pressure control signal pair”, which drives the working fluid flow rate regulating valve. For example: when the pressure is slightly lower than the threshold, the forward delayed signal drives the valve to close slightly (reduces the flow rate and increases the pressure); when the pressure drops suddenly, the reverse delayed signal drives the valve to close significantly, while avoiding superimposition with the pump speed regulation action.

[0032] Through the “complementary signal pair”, the regulation amplitude is precisely controlled, and the delay mechanism is combined to avoid action superimposition, which ensures the regulation accuracy and protects the stability of the thermal reservoir structure.

[0033] In some embodiments, the dual-path regulation module is arranged in a data analysis and processing center, wherein: the first control path is configured with a real-time response channel without delay; and the second control path is configured with a programmable delay chip, and the delay time is dynamically adjusted according to the rock heat capacity characteristics of the thermal reservoir.

[0034] In the above embodiment, the dual-path regulation module is integrated in the data analysis and processing center, the first path is a real-time channel, and the second path realizes dynamic delay adjustment based on rock heat capacity through a programmable delay chip.

[0035] The dual-path regulation module is centralized in the data analysis and processing center, which facilitates the integration of multi-source monitoring data (such as temperature, pressure, and working fluid state) and collaborative calculation. For example, the center can simultaneously receive data from sensors at different depths of the thermal reservoir, and comprehensively judge the authenticity of parameter abnormalities (to avoid false alarms of a single sensor).

[0036] The first control path is configured as a "real-time response channel without delay", adopts a high-speed signal transmission link (such as an optical fiber), ensures that the response time of the temperature signal from collection to generation of an adjustment instruction is less than 0.1 second, and meets the requirement of rapid intervention in an emergency (for example, a sudden temperature rise may cause heat energy depletion of a thermal reservoir, and immediate speed reduction is required).

[0037] The second control path is configured with a programmable delay chip (such as an FPGA chip), and the delay time of the programmable delay chip can be dynamically adjusted according to the rock heat capacity characteristics (ρ·Cp, ρ is the rock density, and Cp is the specific heat capacity) of the thermal reservoir. For example, the heat recovery of a rock with large heat capacity (such as granite) is slow, and the delay time can be set to 30 seconds; the heat recovery of a rock with small heat capacity (such as sandstone) is fast, and the delay time can be set to 10 seconds, so as to ensure that the delay is matched with the characteristics of the thermal reservoir.

[0038] The accuracy of the regulation and control decision is improved through centralized data processing, and the delay time is "adaptively optimized" through programmable hardware, so that the system is suitable for thermal reservoirs with different geological conditions (such as different rock types and different fracture development degrees).

[0039] The application also provides a hydrothermal geothermal reservoir protection method, which comprises the following steps: receiving thermal reservoir monitoring data through the first control path and the second control path in parallel; generating an immediate adjustment instruction in the first control path; injecting a controllable delay in the second control path to generate a delayed adjustment instruction; and interleaving the immediate adjustment instruction and the delayed adjustment instruction to decouple the pressure fluctuation and the temperature fluctuation of the thermal reservoir in the time domain.

[0040] In the above embodiment, the time domain decoupling of the pressure fluctuation and the temperature fluctuation of the thermal reservoir is realized through the steps of "dual-path data reception-differentiated instruction generation-interleaved execution".

[0041] Step 1: Dual-path receiving monitoring data: the temperature, pressure and working medium state data of the thermal reservoir are transmitted into the system through the first and second control paths in parallel, so as to ensure that the data is not missed. For example, the temperature data mainly enters the first path, and the pressure data mainly enters the second path, so as to realize "data shunting processing".

[0042] Step 2: Generate differentiated instructions: the first path generates "immediate adjustment instructions" (such as pump speed reduction instructions when the temperature exceeds a threshold value), without delay, to ensure emergency response; the second path generates "delayed adjustment instructions" (such as flow adjustment instructions when the pressure is abnormal) after injecting a controllable delay (10-30 seconds) into the data.

[0043] Step 3: Interleaved execution of instructions: The execution module first executes the immediate instructions, and then executes the delayed instructions after the delay ends, so that the temperature fluctuations (caused by pump speed adjustment) and pressure fluctuations (caused by flow adjustment) are separated in time (e.g. temperature fluctuations from 0-10 seconds, pressure fluctuations from 10-40 seconds), avoiding the superposition of the two to form "resonant fluctuations".

[0044] Through "action separation in time", the coupling relationship of "temperature and pressure regulation triggered synchronously, leading to parameter fluctuations amplifying each other" in traditional development is broken, and stable control of thermal reservoir parameters is achieved.

[0045] In some embodiments, the delay duration is set to 1.2-1.5 times the thermal recovery period of the thermal reservoir, and is determined by the following steps: measuring the thermal conductivity coefficient of the thermal reservoir rock; calculating the diffusion time of thermal disturbance in the rock; superimposing the convection delay coefficient of the fluid.

[0046] The delay duration is calculated based on the thermal recovery period of the thermal reservoir, specifically through the three steps of "measuring thermal conductivity coefficient - calculating diffusion time - superimposing convection delay", and the value is 1.2-1.5 times the thermal recovery period.

[0047] Definition of thermal recovery period: After the thermal reservoir is disturbed (such as changes in heat flow caused by pump speed adjustment), the natural time length for temperature and pressure to recover to a stable state, mainly determined by the thermal conductivity characteristics of the rock and the convection characteristics of the fluid.

[0048] Delay duration calculation steps: measure the thermal conductivity coefficient (λ) of the thermal reservoir rock: measured by thermal probe method in the well, the larger the λ value (such as metal ore rock), the faster the heat conduction, the shorter the thermal recovery period; By quantifying the physical properties (thermal conductivity, convection) of the thermal reservoir, the delay duration is matched with the recovery ability of the thermal reservoir itself, rather than a fixed value, improving the adaptability of regulation.

[0049] In some embodiments, when generating immediate adjustment instructions: when the temperature exceeds the threshold, immediately reduce the circulating pump speed; when generating delayed adjustment instructions: reduce the working fluid flow after a delay of 10-30 seconds; time interleaving of adjustment actions is formed.

[0050] Based on the priority division of "temperature affecting thermal energy sustainability (requiring emergency response) and pressure affecting structural stability (delayed adjustment)", the dual goals of "preserving thermal energy and structure" are achieved through time interleaving. Immediate adjustment instructions (temperature priority): temperature is a direct indicator of the "thermal energy state" of the thermal reservoir, and temperature exceeding the threshold (such as exceeding the set development temperature by 5°C) means that the heat extraction intensity is too high, which may cause the thermal reservoir to cool down for a long time (thermal energy depletion), so the circulating pump speed needs to be immediately reduced (such as from 3000 r / min to 2700 r / min), reducing the heat extraction amount per unit time, and quickly suppressing temperature rise.

[0051] Delay regulation instruction (pressure hysteresis): Pressure reflects the "fluid balance state" of the thermal reservoir. Abnormal pressure (e.g., 10% lower than the reference pressure) is usually caused by the imbalance between working fluid flow and thermal reservoir fluid supply, but adjusting the flow will change the heat flow distribution, and if it is synchronized with the pump speed reduction action, it may cause a sudden drop in pressure. Therefore, reduce the working fluid flow (e.g., from 100 m 3 / h to 85 m 3 / h) after a delay of 10-30 seconds, and after the temporary pressure fluctuation caused by temperature regulation subsides, stabilize the pressure by adjusting the flow.

[0052] Time interleaving effect: For example, at t=0, the temperature exceeds the threshold, the pump speed starts to decrease (0-5 seconds to complete regulation), and the temperature gradually falls; at t=20 seconds, the pressure is still abnormal, and the flow starts to decrease (20-25 seconds to complete regulation), and the pressure gradually rises. The two regulation actions do not overlap in time, avoiding the superposition of parameter fluctuations.

[0053] In some embodiments, it also includes real-time transmission of monitoring data through 5G communication; generating a pair of complementary control signals in the data analysis center, including: the first group of signals driving the heat exchanger power regulation; the second group of signals driving the back pressure valve opening degree with a delay. In this application, the full-link 5G communication is used for collaborative optimization, and the monitoring data is transmitted to the data analysis center through 5G. The center generates a pair of complementary control signals: the first group of signals driving the heat exchanger power in real time, and the second group of signals driving the back pressure valve opening degree with a delay. The 5G low latency (<1ms) and high bandwidth characteristics realize real-time collaboration of massive data. For example, after uploading the temperature data, the center generates a heat exchanger power regulation signal within 50ms, and simultaneously starts pressure delay calculation; after the delay ends, the back pressure valve opens and closes as needed, avoiding frequent valve action.

[0054] In some embodiments, the second control path includes multi-stage signal processing: the first stage: digital conversion of pressure data; the second stage: injection of programmable time delay; the third stage: generation of working fluid flow control waveform.

[0055] The first stage converts analog pressure signals (such as 4-20mA current signals) to digital signals (such as 0-32767 values) through digital conversion of pressure data, removes signal noise (such as fluctuations caused by electromagnetic interference), and ensures data accuracy. For example, a 16-bit AD converter is used to achieve a resolution of 0.001MPa.

[0056] The second stage injects a programmable delay based on the characteristics of the thermal reservoir (such as rock heat capacity, fracture development state), and injects a delay of 10-30 seconds to the digital signal through a programmable delay chip (such as FPGA). For example, when the fracture development is serious (fluid flow is fast), the delay is set to 10 seconds to quickly stabilize the pressure; when the rock heat capacity is large, the delay is set to 30 seconds to wait for heat recovery.

[0057] The third level generates a working fluid flow control waveform, converts the delayed pressure signal into a PWM (pulse width modulation) waveform, and drives the flow regulating valve. The PWM waveform can achieve smooth regulation of the flow (e.g., ≤3% adjustment per second) by adjusting the pulse width, avoiding pressure shocks caused by sudden opening and closing of the valve.

[0058] In the above embodiment, the temperature / pressure signals are received through two paths, and real-time speed instructions and delayed flow instructions are generated respectively, and the two fluctuation responses are separated in the time axis by staggered execution.

[0059] Signal reception and distribution: temperature signals mainly enter the first control path, and pressure signals mainly enter the second control path, realizing independent regulation links of "temperature-speed" and "pressure-flow".

[0060] The first path generates a circulating pump speed regulation instruction in real time: when the temperature exceeds the threshold, the speed is immediately reduced (e.g., 2% reduction per 1°C increase), and when the temperature is below the threshold, the speed is slowly increased (e.g., 1% increase per 0.5°C decrease); The second path injects a programmable delay to generate a flow regulation instruction: when the pressure is below the threshold, the flow is reduced after a delay (e.g., 5% reduction per 0.1 MPa decrease), and when the pressure is above the threshold, the flow is increased after a delay.

[0061] Staggered execution logic: the execution module ensures that the execution time of the speed instruction and the flow instruction does not overlap through a timing controller. For example, the execution window of the speed regulation is t=0-5 seconds, and the execution window of the flow regulation is t=20-25 seconds, and the two are separated by 15 seconds in the time axis, so that the temperature fluctuation (0-10 seconds) and the pressure fluctuation (20-30 seconds) are completely separated.

[0062] Through the whole process design of "signal distribution-independent instruction-time isolation", the coupling relationship between temperature and pressure fluctuations is fundamentally broken, the thermal reservoir parameters are always in a stable and controllable state, and the "parameter resonance" problem in traditional development is avoided.

[0063] The programmable delay duration is dynamically calculated by the following formula: t_{delay} = k * L / (ρ * c * λ), where k is an adjustment coefficient of 1.2-1.5, ρ is the rock density (kg / m 3 ), C p is the specific heat capacity of rock (J / kg·K), L is the disturbance propagation distance (m), and λ is the thermal conductivity (W / m·K). The constraint condition is: 10 seconds ≤ t_{delay} ≤ 30 seconds. The delay duration is not a fixed value, but is dynamically optimized according to the geological characteristics of the thermal reservoir. The rock heat capacity (ρ· Cp) Determine the thermal disturbance absorption capacity, thermal conductivity (λ) affects the diffusion speed. By updating the fracture state (L) in real time, the system adapts to the thermal reservoir heterogeneity. For example, increasing L when the fracture is developed can prolong the delay to avoid high-pressure fluid along the new fracture; shorten the delay to quickly stabilize the pressure when the injection-production ratio is insufficient. This mechanism matches the regulation response with the formation thermal recovery period, improving the thermal reservoir life compared to the fixed delay strategy.

[0064] In the above embodiment, the disturbance propagation distance L is updated in real time by the following method: deploy a magnetotelluric sounder to monitor the fracture development state of the thermal reservoir; when the fracture expansion rate >5% / month, the L value increases by 20%; when the injection-production ratio <0.8, the L value decreases by 15%.

[0065] In the above embodiment, the first control path includes: temperature signal analog-to-digital conversion (response time <0.1 seconds); generating a complementary pair of speed control signals; driving the frequency converter to adjust the circulating pump speed, with a regulation amplitude of ±5% of the rated value. The second control path includes: pressure signal digital filtering (cutoff frequency 0.1 Hz); injecting programmable delay through field programmable gate array; generating pulse width modulation waveform to control the opening degree of the flow valve, with a regulation amplitude of ±15%.

[0066] Based on the development concept of "taking heat without taking water", through the innovative design of "double-path regulation + time domain decoupling", the application solves the problems of thermal reservoir pressure imbalance, ground subsidence and pollution caused by traditional water-taking development. The core principle is: real-time parameter monitoring: through high-precision sensors and 5G communication, real-time capture of thermal reservoir temperature, pressure and working medium state; regulation path differentiation: the first path (temperature-pump speed) has no delay response, ensuring the sustainability of thermal energy; the second path (pressure-flow) has a delay of 10-30 seconds, ensuring the stability of the structure; execution timing interleaving: through complementary signal pairs and programmable delay, the regulation actions of temperature and pressure are separated on the time axis, avoiding fluctuation superposition; delay time dynamic: based on the physical properties of thermal reservoir rock heat capacity, thermal conductivity coefficient, etc., the delay time (1.2-1.5 times of the thermal recovery period) is dynamically calculated to ensure matching with the recovery capacity of the thermal reservoir. Through the above technology, the synergy of "efficient heat extraction" and "thermal reservoir protection" in geothermal resource development is realized, providing a systematic solution for the sustainable utilization of hydrothermal geothermal resources.

[0067] In the foregoing specification, examples have been described with reference to specific example embodiments. It will be evident, however, that various modifications and changes can be made thereto without departing from the scope as set forth in the following claims. The claims are not limited to the specific examples described above.

Claims

1. A hydrothermal geothermal reservoir protection system, characterized in that: include: Thermal reservoir parameter monitoring module, used to collect thermal reservoir temperature, pressure and circulating fluid state parameters in real time; Dual-path control module, including: a first control path that directly responds to monitoring data and generates a primary regulation signal; A second control path, connected in parallel to the first control path and configured with a delay unit, for generating a delayed secondary adjustment signal; The execution module receives the primary adjustment signal and the secondary adjustment signal, and controls the rotation speed of the circulation pump and the working fluid flow rate respectively through staggered execution timing, so as to decouple abnormal fluctuations of thermal reservoir parameters in the time domain.

2. The hydrothermal geothermal reservoir protection system according to claim 1, characterized in that: The delay time of the delay unit is set to 10-30 seconds, which allows the thermal reservoir to recover stability from the disturbance caused by the primary regulating signal before the secondary regulating signal is triggered.

3. The hydrothermal geothermal reservoir protection system according to claim 1, characterized in that: The first control path includes: a data conversion unit, converting the temperature monitoring signal into a complementary temperature control signal pair; The temperature control signal directly drives the circulating pump frequency converter; The second control path includes: a delay processing unit, delaying the pressure monitoring signal to generate a complementary delayed pressure control signal pair; The delayed pressure control signal drives the working medium flow regulating valve.

4. The hydrothermal geothermal reservoir protection system according to claim 1, characterized in that: The dual-path control module is set in the data analysis and processing center, wherein: The first control path configures a real-time response channel without delay; The second control path is configured with a programmable delay chip, and the delay duration is dynamically adjusted according to the heat capacity characteristics of the thermal reservoir rock.

5. A hydrothermal geothermal reservoir protection method, characterized in that: The steps include: receiving thermal reservoir monitoring data via a first control path and a second control path connected in parallel; generating an immediate adjustment instruction in a first control path; generating a delay adjustment instruction after injecting a controllable delay in the second control path; The immediate adjustment instructions and the delayed adjustment instructions are executed alternately to decouple the pressure fluctuation and temperature fluctuation of the thermal reservoir in the time domain.

6. The hydrothermal geothermal reservoir protection method according to claim 5, characterized in that: The delay time is set to 1.2-1.5 times the thermal recovery period of the thermal reservoir, which is specifically determined by the following steps: Measure the thermal conductivity of thermal reservoir rocks; Calculate the time it takes for thermal disturbances to diffuse through rocks; Superimposed fluid convection delay coefficient.

7. The hydrothermal geothermal reservoir protection method according to claim 5, characterized in that: When generating an immediate adjustment instruction: When the temperature exceeds the threshold, the circulation pump speed is immediately reduced; When generating delay adjustment instructions: Reduce the working fluid flow after a delay of 10-30 seconds; The time staggering of the adjustment action is formed.

8. The hydrothermal geothermal reservoir protection method according to claim 5, characterized in that: Also includes: Real-time transmission of monitoring data via 5G communications; Generate complementary control signal pairs at the data analysis center, including: The first set of signals drives the heat exchanger power regulation; The second set of signals generated with a delay drives the back pressure valve opening.

9. The hydrothermal geothermal reservoir protection method according to claim 5, characterized in that: The second control path includes multiple stages of signal processing: Level 1: Digital conversion of pressure data; Second stage: injecting programmable time delay; Level 3: Generate working fluid flow control waveform.

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