System for observing recharge rate of geothermal well

Abstract

The invention belongs to the technical field of geothermal resource monitoring, and discloses a system for observing the recharge rate of a geothermal well, which comprises a main control unit and a data acquisition module, a man-machine interaction module and a communication module which are connected with the main control unit. The data acquisition module synchronously acquires flow, temperature and pressure data of the mining well and the recharge well. The main control unit firstly analyzes pressure-flow velocity long-time covariance, temperature-flow velocity medium-time response and flow velocity instantaneous stability to comprehensively calculate a reliability index of flow data; and physical rule verification is executed, and when the monitored value is inconsistent with the trend reflected by the pressure and the temperature, the equipment fault is judged. Calculating a stage recharge rate based on high-reliability data, if the stage recharge rate does not reach the standard, carrying out intelligent diagnosis, and if the data reliability is low or equipment failure exists, giving an alarm to indicate that the measurement is abnormal; if the data are reliable, an alarm is given to indicate suspected illegal mining or blockage of the recharge well. According to the invention, the data credibility and the supervision accuracy are improved, and the intelligent positioning of the abnormal source is realized.

Description

Technical Field

[0001] This invention relates to the field of geothermal resource monitoring technology, and in particular to a system for observing the reinjection rate of geothermal wells. Background Technology

[0002] Geothermal water is a type of hot water resource originating from deep within the Earth, widely distributed and utilized in my country. Geothermal water is extracted through artificially drilled wells and used for heating in buildings, industrial applications, and agricultural activities. Due to the limited underground resources and the large scale of geothermal water extraction, Chinese policy requires that after the heat is extracted, the geothermal water be returned to the Earth's depths through another well to prevent geological depletion and potential landslides or other hazards.

[0003] Existing systems rely excessively on single-point flowmeter data, failing to effectively identify data inaccuracies caused by sensor malfunctions, signal interference, calibration drift, or unfavorable installation environments (such as air pollution or vibration). Directly using this distorted data to calculate key indicators like reinjection rates can lead to regulatory misjudgments, potentially unfairly impacting compliant operators or masking genuine violations or engineering problems. Furthermore, the lack of real-time analysis of the inherent physical relationships between multiple parameters such as flow, temperature, and pressure prevents quantitative assessment and continuous tracking of monitoring data quality. Consequently, the system cannot identify potential risks at the data generation stage and cannot provide verifiable technical evidence for the validity of historical data and the impartiality of regulatory decisions. Summary of the Invention

[0004] To overcome the technical defects of existing technologies, this invention provides a system for observing the reinjection rate of geothermal wells, comprising a main control unit integrated within a protective enclosure; a data acquisition module, a human-machine interaction module, and a communication interface electrically connected to the main control unit;

[0005] The data acquisition module is used to simultaneously acquire flow rate data, temperature data, and pressure data of at least one production well and at least one reinjection well; The main control unit is configured to: calculate the reliability index of the flow data of each well based on the collected flow data, temperature data and pressure data; calculate the stage reinjection rate based on the cumulative flow growth value of reinjection wells and production wells within a calculation cycle; and generate a diagnostic conclusion based on the reliability index if the stage reinjection rate is lower than the preset threshold. The human-computer interaction module is used to display the reliability index, the stage reinjection rate, the system status, and alarm information.

[0006] Preferably, the main control unit includes a flow data reliability index calculation module, which is configured to calculate the reliability index by analyzing the coordinated changes in temperature, pressure, and flow rate, specifically including:

[0007] The pressure-velocity covariance analysis unit is used to calculate the pressure-velocity covariance index based on the consistency of the changing trends of average pressure and average velocity within a preset first time window. The temperature-flow velocity response analysis unit is used to calculate the temperature-flow velocity response index based on the consistency of the changing trends of the average temperature and average flow velocity within a preset second time window. The velocity stability analysis unit is used to calculate the velocity stability index based on the coefficient of variation of the instantaneous velocity sequence over a short period of time. The index fusion unit is used to perform weighted fusion of the pressure-flow rate covariance index, the temperature-flow rate response index, and the flow rate stability index to obtain the comprehensive reliability index.

[0008] Preferably, the first time window is at the 10-minute level; the pressure-flow rate covariance analysis unit is configured to assign a high exponent value if the average pressure increases and the average flow rate increases synchronously, or if the average pressure remains or decreases and the average flow rate remains or decreases synchronously; if the trends are contradictory, a low exponent value is assigned.

[0009] Preferably, the second time window is at the 3-minute level; the temperature-flow rate response analysis unit is configured to: assign a high index value if the average temperature rises above the first temperature threshold and the average flow rate rises synchronously, or if the average temperature falls above the second temperature threshold and the average flow rate falls synchronously; assign a low index value if the trends are seriously inconsistent.

[0010] Preferably, the flow velocity stability analysis unit is configured to: collect instantaneous flow velocity at a preset high-frequency period, and calculate the average value and standard deviation of the instantaneous flow velocity within the period at a minute-level period; calculate the coefficient of variation, and if the coefficient of variation is less than or equal to a preset stability threshold, assign a high exponent value; if the coefficient of variation is greater than the stability threshold, the exponent value decreases as the coefficient of variation increases.

[0011] Preferably, the main control unit further includes a reinjection compliance diagnosis module, which is configured to execute the following logic: if the stage reinjection rate is lower than a preset compliance threshold, then determine whether the reliability index of both the production well and the reinjection well is higher than a preset confidence threshold; if not, then generate a first type of alarm conclusion indicating abnormal measurement equipment data; if yes, then generate a second type of alarm conclusion indicating suspected illegal production or blockage of the reinjection well.

[0012] Preferably, the main control unit is configured to: when calculating the stage reinjection rate, preferentially use the flow data with a reliability index higher than a preset screening threshold for cumulative flow calculation.

[0013] Preferably, the data acquisition module acquires instantaneous flow data at a frequency of not less than twice per second, and acquires temperature and pressure data at a frequency of not less than once per second.

[0014] Preferably, the diagnostic method of the system includes the following steps: high-frequency synchronous acquisition of flow rate, temperature, and pressure data of production wells and reinjection wells; analysis of the synergistic change relationship between data based on the "temperature-pressure-flow rate" relationship model, and calculation of the reliability index of flow rate data for each well; calculation of the stage reinjection rate based on reliable cumulative flow rate data within a calculation cycle; comparison of the stage reinjection rate with a preset threshold; if the stage reinjection rate does not meet the threshold, the root cause of the problem is determined based on the reliability index, and corresponding diagnostic conclusions and alarm information are generated.

[0015] Preferably, determining the root cause of the problem based on the reliability index specifically includes: if the reliability index of either the production well or the reinjection well is lower than a preset confidence threshold, then the root cause of the problem is determined to be abnormal measurement equipment data; if the reliability indices of both the production well and the reinjection well are higher than the preset confidence threshold, then the root cause of the problem is determined to be suspected illegal mining or blockage of the reinjection well.

[0016] The beneficial effects of this invention are:

[0017] This invention establishes a multi-physical quantity collaborative verification model of "pressure-temperature-flow rate" to cross-verify the reliability of flow data across three time scales: long-term trend, medium-term response, and instantaneous fluctuation. It also incorporates a built-in rule that "device failure indicates a trend discrepancy," fundamentally solving the data distortion problems caused by interference and drift in traditional single-flow monitoring. This provides a solid and reliable data foundation for all subsequent calculations and decisions. When the reinjection rate fails to meet standards, the system can intelligently distinguish whether the problem originates from abnormal front-end measuring equipment or from back-end operational violations or geological engineering issues (such as illegal mining or blockage of reinjection wells). This leap from "alarm" to "diagnosis" significantly shortens troubleshooting time, provides clear direction for operation and maintenance, and offers precise targeting for regulatory enforcement, significantly improving management efficiency.

[0018] This invention, through precise monitoring and timely early warning, helps to detect signs of blockage in reinjection wells at an early stage, reminding people to take maintenance measures and ensuring the long-term effectiveness of reinjection projects. At the same time, it can effectively deter and identify illegal over-extraction behavior, ensuring the balance and long-term stability of geothermal field extraction and injection from a technical perspective, and supporting the green and sustainable development and utilization of geothermal resources. Attached Figure Description

[0019] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0020] Figure 1 This is a schematic diagram of the system of the present invention;

[0021] Figure 2 This is a schematic diagram of the process of the present invention.

[0022] Figure labeling: 1. Main control unit; 11. Reliability index calculation module; 111. Pressure-flow rate covariance analysis unit; 112. Temperature-flow rate response analysis unit; 113. Flow rate stability analysis unit; 114. Index fusion unit; 12. Recharge compliance diagnosis module; 2. Data acquisition module; 3. Human-machine interaction module; 31. Touch screen; 32. Status indicator light; 33. Audible and visual alarm; 4. Communication interface; 5. Protective enclosure. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the various embodiments of this invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the various embodiments of this invention to facilitate a better understanding of this application. However, the technical solutions claimed in the claims of this application can be implemented even without these technical details and with various variations and modifications based on the following embodiments.

[0024] like Figures 1 to 2 As shown, this embodiment provides a system for observing the reinjection rate of geothermal wells. The field portion of this system is installed in an outdoor enclosure with an IP65 protection rating. The enclosure integrates an industrial-grade embedded main controller (main control unit), a power module, a signal conditioning module, and a 4G DTU (communication interface). The data acquisition module is connected via shielded cables to the flow meter (electromagnetic), temperature sensor (Pt100), and pressure transmitter at the wellheads of the production and reinjection wells. After the system is powered on, the data acquisition module begins operation: flow signals are acquired at a frequency of 2Hz, and temperature and pressure signals are acquired at a frequency of 1Hz. All raw data is sent to the main control unit in real time.

[0025] Data acquisition module 2 is connected to main control unit 1 via industrial-grade terminal blocks. Its core includes a multi-channel isolated digital input circuit (for acquiring pulse flow data), a high-precision analog input conditioning circuit (for acquiring 4-20mA temperature and pressure data), and an RS-485 communication interface circuit (for acquiring smart instrument data using the Modbus protocol). All input channels employ optoelectronic or magnetoelectric isolation technology and are equipped with transient voltage suppression devices to adapt to the harsh electromagnetic environment of the well site.

[0026] The human-machine interaction module 3 includes a 7-inch industrial-grade resistive touch display 31, a set of three-color (green / yellow / red) high-brightness LED status indicators 32 and a high-decibel sound and light alarm 33. The display communicates with the main control unit through the LVDS interface.

[0027] The communication interface module 4 can be equipped with a 4G / 5G wireless communication module or an industrial Ethernet interface for remote data transmission.

[0028] All of the above modules are integrated inside the protective enclosure 5. The enclosure is made of high-strength ABS engineering plastic injection molding, achieving an IP66 protection level. The enclosure cover 51 is made of transparent acrylic material and is sealed to the enclosure by silicone sealing strips and waterproof buckles around the perimeter. Multiple waterproof cable glands are provided on the back of the enclosure for cable entry.

[0029] The main control unit 1 is integrated inside the protective enclosure; the data acquisition module 2, the human-machine interaction module 3, and the communication interface 4 are electrically connected to the main control unit 1;

[0030] The data acquisition module 2 is used to simultaneously acquire flow rate data, temperature data, and pressure data of at least one production well and at least one reinjection well; The main control unit 1 is configured to: calculate the reliability index of the flow data of each well based on the collected flow data, temperature data and pressure data; calculate the stage reinjection rate based on the cumulative flow growth value of reinjection wells and production wells within a calculation cycle; and generate a diagnostic conclusion based on the reliability index if the stage reinjection rate is lower than the preset threshold. The human-computer interaction module 3 is used to display the reliability index, the stage reinjection rate, the system status, and alarm information.

[0031] The main control unit 1 includes a flow data reliability index calculation module 11. This module is configured to calculate the reliability index by analyzing the inherent physical correlation between temperature, pressure, and flow rate, thereby achieving a quantitative assessment of the data's reliability. Specifically, it includes:

[0032] Pressure-flow rate covariance analysis unit 111: This unit calculates the pressure-flow rate covariance index based on the consistency of the changing trends of average pressure and average flow rate within a preset 10-minute time window. Its design basis and advantages are: the pressure response is on the order of seconds, and its changes are directly related to pump work and pipeline resistance. Observing over a longer 10-minute timescale, a stable increase in pressure usually corresponds to an increase in flow rate, while a stable or decreasing pressure may indicate a decrease in flow rate. This analysis can effectively identify long-term deviations in the trends caused by pressure sensor malfunction or flow meter jamming.

[0033] Temperature-flow-velocity response analysis unit 112: This unit calculates the temperature-flow-velocity response index based on the consistency of the trends in average temperature and average flow rate within a preset second time window of 3 minutes. Its design and configuration are based on the following: the temperature response is relatively slow, approximately on the order of 10 seconds, and its rise typically indicates the passage of a hot water mass. Specifically, this unit is configured as follows: if the average temperature rises by more than 1°C and the average flow rate rises simultaneously, or if the average temperature falls by more than 1°C and the average flow rate falls simultaneously, a high index value is assigned, consistent with physical laws; if the average temperature remains stable, the expected flow rate is also stable; if there is a significant discrepancy between the temperature and flow rate trends (e.g., a significant temperature rise while the flow rate remains unchanged or decreases), a low index value is assigned. Its advantage lies in its ability to sensitively capture logical contradictions between the thermodynamic and kinematic properties of the fluid, which is crucial for diagnosing anomalies in flow data.

[0034] Flow velocity stability (air / interference) analysis unit 113: This unit calculates the flow velocity stability index based on the coefficient of variation (CV) of instantaneous flow velocity sequences over a short period, and is particularly useful for detecting air content in water flow or installation problems. Its design and configuration are based on the principle of fast flow velocity response but high volatility. This unit collects instantaneous flow velocities at a high-frequency cycle of 2 seconds and calculates the average (A) and overall standard deviation (B) of 30 instantaneous flow velocity samples within a minute. The CV is then calculated (CV = B / A). The judgment logic is as follows: if the CV ≤ 5%, the flow is considered stable, and a high stability index value is assigned; if CV > 5%, the index value decreases significantly as CV increases. Based on this, the system can determine that the water flow may have excessive air content during this time period, or that there are equipment quality problems such as vibration or insufficient straight pipe sections in the flowmeter installation environment. This analysis provides in-depth insight into the sources of data noise.

[0035] The index fusion and equipment problem comprehensive judgment unit 114 is used to perform weighted fusion of the pressure-flow rate covariance index, the temperature-flow rate response index, and the flow rate stability index to obtain the comprehensive reliability index (R). Furthermore, this unit is configured to execute a key judgment rule: if the expected flow rate direction (increase / decrease / stable) reflected by the pressure and temperature change trends is significantly contrary to the measured flow rate change trend, then regardless of the weighted score, it can be directly determined that the flow meter equipment has a fundamental problem (such as impeller jamming, probe scaling, or circuit failure), and a corresponding equipment fault mark is generated. Its advantage lies in achieving multi-dimensional information fusion and the mandatory execution of key physical rules, ensuring zero tolerance for hard equipment faults and rapid identification.

[0036] The backfill compliance diagnostic module 12 is configured to execute the following intelligent diagnostic logic: if the backfill rate of the stage is lower than a preset compliance threshold, then the diagnostic process is initiated:

[0037] First, check the reliability index (R) of the flow data for the production well and the reinjection well, and whether there is an "equipment fault marker" generated by unit 114.

[0038] If the R value of any well is lower than the preset confidence threshold or a "device fault marker" is present, the system generates a first-type alarm conclusion indicating "abnormal or faulty measurement equipment data". Its advantage is that it can immediately prompt maintenance personnel to check instruments and wiring, preventing misjudgments and resource waste due to equipment problems.

[0039] If the R-values ​​of both wells are higher than the preset reliability threshold and there are no equipment fault markers, indicating that the data is highly reliable, a second type of alarm conclusion is generated indicating "suspected illegal mining (excessive mining volume) or reinjection well blockage (insufficient injection capacity)". Its advantage lies in that, after ruling out data quality issues, it focuses the problem on substantive operational management or geological engineering issues, providing regulatory personnel with a clear direction for investigation or key evidence for process adjustments.

[0040] Further optimized, the main control unit 1 is configured to: when calculating the stage reinjection rate, prioritize the use of traffic data with a reliability index higher than a preset screening threshold and no equipment fault markers for cumulative traffic calculation. Its advantage lies in that this strategy automatically filters out low-quality data segments and data from periods with known faults, ensuring the accuracy and fairness of the calculation basis for the core regulatory indicator (reinjection rate).

[0041] The system operates by including the following steps: S1: High-frequency synchronous acquisition: Instantaneous flow data is acquired twice per second through data acquisition module 2, and temperature and pressure data are acquired once per second.

[0042] S2: Multi-scale Reliability Index Calculation and Equipment Diagnosis: The long-term covariance trend of pressure and flow rate is analyzed based on a 10-minute window. The temperature-flow rate response relationship is analyzed based on a 3-minute window, applying a significance threshold of 1℃. The flow rate variation coefficient is calculated based on a 1-minute window (containing 30 sampling points), applying a stability threshold of 5% to determine gas content or installation interference. The above indices are combined to obtain the reliability index (R), and the rule that "if the pressure-temperature trend contradicts the measured flow rate value, the equipment is considered faulty" is enforced.

[0043] S3: Accumulated Reliable Data and Recharge Rate Calculation: Within a calculation period, the flow data of all production wells and recharge wells that meet the reliability index and have no fault markers are accumulated to obtain the credible cumulative production volume (Q_s) and credible cumulative recharge volume (Q_r) respectively. The recharge rate η = Q_r / Q_s is calculated during the calculation period.

[0044] S4: Compliance Assessment and Intelligent Diagnosis: If η ≥ preset compliance threshold, the process ends. If η < preset compliance threshold: then... a. Abnormal data path: If the R value of the production well or the reinjection well is lower than the confidence threshold or there is an equipment fault mark, it is determined as "abnormal or faulty measurement equipment data".

[0045] b. Operational / Geological Issues Path: If the data from both wells are reliable (high R-value, no faults), then it is determined as "suspected illegal mining or blockage of the reinjection well".

[0046] S5: Result output: Generate corresponding diagnostic conclusions and alarm information, and display them through the human-computer interaction module (3).

[0047] The system design closely aligns with the physical characteristics of geothermal fluids: rapid pressure response, slow temperature response, and large flow velocity fluctuations. By setting differentiated analysis time windows (10 minutes, 3 minutes, 1 minute) and reasonable thresholds (1℃, 5%), the model better reflects actual processes, and the diagnostic conclusions align more with engineering intuition. The newly added rules of "contradictory trends indicate equipment failure" and "high coefficient of variation warns of gas content / installation problems" provide more specific and direct fault indications beyond the comprehensive indicator of "reliability index," greatly facilitating rapid repairs by on-site maintenance personnel. This invention, through the dual logic of "using only reliable data to calculate regulatory indicators" and "verifying data before determining violations," ensures that the final "suspected violation" conclusion is based on indisputable data quality, enhancing the authority and impartiality of supervision and making it more convincing to those being managed.

[0048] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A system for observing the recharge rate of a geothermal well, characterized in that, The main control unit (1) is integrated into the protective enclosure; the data acquisition module (2), the human-machine interaction module (3) and the communication interface (4) are electrically connected to the main control unit (1); The data acquisition module (2) is used to simultaneously acquire flow rate data, temperature data and pressure data of at least one production well and at least one reinjection well; The main control unit (1) is configured to: calculate the reliability index of the flow data of each well based on the collected flow data, temperature data and pressure data; calculate the stage reinjection rate based on the cumulative flow growth value of the reinjection well and the production well within a calculation cycle; and generate a diagnostic conclusion based on the reliability index if the stage reinjection rate is lower than the preset threshold. The human-computer interaction module (3) is used to display the reliability index, the stage reinjection rate, the system status, and alarm information.

2. The system for observing the recharge rate of a geothermal well according to claim 1, characterized in that, The main control unit (1) includes a reliability index calculation module (11) for flow data. The reliability index calculation module (11) is configured to calculate the reliability index by analyzing the coordinated changes in temperature, pressure, and flow rate, specifically including: The pressure-velocity covariance analysis unit (111) is used to calculate the pressure-velocity covariance index based on the consistency of the changing trends of average pressure and average velocity within a preset first time window. Temperature-flow velocity response analysis unit (112) is used to calculate temperature-flow velocity response index based on the consistency of the changing trends of average temperature and average flow velocity within a preset second time window. The velocity stability analysis unit (113) is used to calculate the velocity stability index based on the coefficient of variation of the instantaneous velocity sequence over a short period of time. The index fusion unit (114) is used to perform weighted fusion of the pressure-flow rate covariance index, the temperature-flow rate response index and the flow rate stability index to obtain the comprehensive reliability index.

3. The system for observing the recharge rate of a geothermal well of claim 2, wherein: The first time window is at the 10-minute level; the pressure-flow rate covariance analysis unit (111) is configured to: assign a high index value if the average pressure increases and the average flow rate increases synchronously, or if the average pressure remains or decreases and the average flow rate remains or decreases synchronously; assign a low index value if the trends are opposite.

4. The system for observing the recharge rate of a geothermal well of claim 2, wherein: The second time window is at the 3-minute level; the temperature-flow rate response analysis unit (112) is configured to: assign a high index value if the average temperature rises above the first temperature threshold and the average flow rate rises synchronously, or the average temperature falls above the second temperature threshold and the average flow rate falls synchronously; assign a low index value if the trend is seriously inconsistent.

5. The system for observing the recharge rate of a geothermal well of claim 2, wherein: The flow velocity stability analysis unit (113) is configured to: collect instantaneous flow velocity at a preset high-frequency period, and calculate the average value and standard deviation of instantaneous flow velocity within the period at a minute-level period; calculate the coefficient of variation, and if the coefficient of variation is less than or equal to a preset stability threshold, assign a high exponent value; if the coefficient of variation is greater than the stability threshold, the exponent value decreases as the coefficient of variation increases.

6. The system for observing the recharge rate of a geothermal well of claim 1, wherein, The main control unit (1) also includes a reinjection compliance diagnosis module (12), which is configured to execute the following logic: if the stage reinjection rate is lower than the preset compliance threshold, then determine whether the reliability index of the mining well and the reinjection well is higher than the preset confidence threshold; if not, then generate a first type of alarm conclusion indicating abnormal measurement equipment data; if yes, then generate a second type of alarm conclusion indicating suspected illegal mining or blockage of the reinjection well.

7. The system for observing the recharge rate of a geothermal well of claim 1, wherein, The main control unit (1) is configured to: when calculating the stage recharge rate, prioritize the use of flow data with a reliability index higher than the preset screening threshold for cumulative flow calculation.

8. The system for observing the recharge rate of a geothermal well according to any one of claims 1 to 7, characterized in that, The data acquisition module (2) acquires instantaneous flow data at a frequency of no less than twice per second, and acquires temperature and pressure data at a frequency of no less than once per second.

9. The system for observing geothermal well reinjection rate according to any one of claims 1 to 8, characterized in that, The diagnostic method of the system includes the following steps: high-frequency synchronous acquisition of flow rate, temperature, and pressure data of production wells and reinjection wells; analysis of the synergistic changes between data based on the "temperature-pressure-flow rate" relationship model, and calculation of the reliability index of flow rate data for each well; calculation of the stage reinjection rate based on reliable cumulative flow rate data within a calculation cycle; comparison of the stage reinjection rate with a preset threshold; if the stage reinjection rate does not meet the threshold, the root cause of the problem is determined based on the reliability index, and corresponding diagnostic conclusions and alarm information are generated.

10. The system for observing geothermal well reinjection rate according to claim 9, characterized in that, The method of determining the root cause of a problem based on the reliability index specifically includes: if the reliability index of any well in the production well or the reinjection well is lower than a preset confidence threshold, the root cause of the problem is determined to be abnormal measurement equipment data; if the reliability index of both the production well and the reinjection well is higher than the preset confidence threshold, the root cause of the problem is determined to be suspected illegal production or blockage of the reinjection well.

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