Measurement and control method and system for stable high-pressure water injection

Abstract

The invention discloses a measurement and control method for stable high-pressure water injection, and relates to the oilfield water injection technology. Related data in the water injection process are obtained; based on the flow related parameters and the water injection related data, utilizing a temperature influence model, a pressure control model and a corrosion evaluation and compensation model to comprehensively calculate a corrected flow value; if the collected flow is not consistent with the target flow, the opening degree of a flow adjusting valve is calculated according to set parameters; and regulating and controlling according to the calculated opening degree of the flow valve by utilizing an executing mechanism. An intelligent measurement and control system integrating multi-parameter real-time monitoring, multi-model cooperative calculation and self-adaptive dynamic regulation and control is constructed, comprehensive sensing and accurate processing of temperature and pressure changes and equipment corrosion conditions in the water injection process are achieved, and therefore stable and efficient operation of the high-pressure water injection process is guaranteed, the water injection quality is remarkably improved, and the water injection cost is reduced. The service life of water injection equipment is effectively prolonged, and production cost and safety risks are reduced.

Description

Technical Field

[0001] The present application relates to the technical field of oilfield water injection, and in particular to a measurement and control method and system for stable high-pressure water injection. Background Art

[0002] In high-pressure water injection operations in industries like oil extraction, the stability and accuracy of the injection process are crucial for maintaining formation pressure and improving oil recovery. However, actual operating conditions are extremely complex and subject to numerous interfering factors. For one thing, formation temperature varies significantly with depth. Temperature differences between different regions can alter the physical properties of the injected water (such as viscosity and density), affecting injection flow and oil recovery efficiency. Furthermore, pressure fluctuations in high-pressure environments can not only destabilize the injection flow but also cause structural damage to the injection equipment. Furthermore, chemical reactions between the injected water, the formation material, and the equipment itself can easily cause corrosion, which not only reduces equipment lifespan but also significantly increases maintenance costs and safety risks.

[0003] Currently, traditional high-pressure water injection measurement and control methods mostly consider only a single or a few influencing factors, lacking the ability to comprehensively address multiple factors such as temperature, pressure, and corrosion. This results in low control accuracy and an inability to meet the requirements for stable water injection under complex operating conditions. While some methods incorporate PID control algorithms, these fixed parameters make them difficult to adapt to dynamic operating conditions. These methods suffer from slow response and large overshoot, severely impacting water injection effectiveness and equipment stability. Summary of the Invention

[0004] The embodiments of the present application provide a stable high-pressure water injection measurement and control method and system for comprehensively considering the influence of multiple factors and realizing dynamic and precise control of high-pressure water injection measurement and control.

[0005] The present application provides a method for measuring and controlling stable high-pressure water injection, including: Collect flow-related parameters of the pipe section; as well as relevant data during the water injection process; Based on the flow-related parameters and water injection-related data, a temperature influence model, a pressure control model, and a corrosion assessment and compensation model are used to comprehensively calculate and obtain a corrected flow value; If the collected flow rate is inconsistent with the target flow rate, the flow valve opening is calculated based on the set parameters; The actuator is used to control the flow valve opening according to the calculated flow valve opening.

[0006] The present application provides a measurement and control system for stable high-pressure water injection, including: Data acquisition module, used to collect flow-related parameters of the pipe section; as well as relevant data during the water injection process; The intelligent control table head is used for obtaining a corrected flow value through comprehensive calculation based on the flow-related parameters, the related data of water injection, a temperature influence model, a pressure control model, and a corrosion evaluation and compensation model. If the collected flow is inconsistent with the target flow, the opening of the flow valve is calculated according to the set parameters; The actuator adjusts and controls the opening of the flow valve according to the flow valve opening calculated by the intelligent control table head.

[0007] The embodiments of the present application construct an intelligent measurement and control system integrating real-time multi-parameter monitoring, multi-model collaborative calculation, and self-adaptive dynamic regulation, realize comprehensive perception and accurate processing of temperature, pressure change, and equipment corrosion in the water injection process, and perform real-time optimization calculation and dynamic regulation on the water injection parameters by using complex algorithms, so as to ensure stable and efficient operation of the high-pressure water injection process, significantly improve the water injection quality, effectively prolong the service life of the water injection equipment, and reduce the production cost and safety risk.

[0008] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application, the embodiments can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0009] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of the preferred embodiments and are not meant to limit the present application. Moreover, the same reference numerals in the attached drawings indicate the same or similar components. In the drawings: Figure 1 The basic flow of the measurement and control method for stable high-pressure water injection of the embodiments of the present application is shown. DETAILED DESCRIPTION

[0010] Exemplary embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be accurately conveyed to those skilled in the art.

[0011] The embodiments of the present application provide a measurement and control method for stable high-pressure water injection, as shown in Figure 1 The method comprises the following steps: In step S101, flow-related parameters of the pipe section are collected, and related data in the water injection process are collected. In some embodiments, the flow-related parameters include: pipe segment instantaneous flow value, cumulative flow value, temperature value, pressure value, pipe segment thickness; The relevant data in the water injection process includes flow, temperature, pressure, and equipment corrosion data. In a specific example, various sensors are reasonably deployed at key positions of the water injection pipeline and equipment to collect real-time key data. Among them, the flow meter is used to accurately measure the pipe segment instantaneous flow value and the cumulative flow value; the temperature sensor acquires the fluid temperature in real time; the pressure sensor group collects pressure data at different positions to calculate the pressure difference; the ultrasonic thickness gauge regularly monitors the pipeline thickness to obtain data related to the degree of equipment corrosion, ensuring that the running state information during the water injection process is comprehensively and accurately mastered.

[0012] In step S102, based on the flow-related parameters and the relevant data of water injection, the corrected flow value is calculated by using the temperature influence model, the pressure control model, and the corrosion evaluation and compensation model. Specifically, this part can be realized by an intelligent control table header. As the core, the intelligent control table header is built-in with various algorithms. After receiving the multi-source data of temperature, pressure, flow, corrosion, etc. transmitted by the data acquisition module, the temperature influence model, the pressure control model, the corrosion evaluation and compensation model, and the adaptive PID feedback control algorithm are used for comprehensive processing.

[0013] For example, in a specific example, first, the temperature influence model corrects the parameters required for flow calculation according to the established function relationship between the physical properties of injected water and temperature; the pressure control model establishes the dynamic relationship between pressure and flow based on the principles of fluid mechanics, combining Bernoulli's equation and the continuity equation, and calculates the required adjusted flow value according to the current pressure state; the corrosion evaluation and compensation model evaluates the degree of equipment corrosion in combination with the material properties and service time of the equipment, and compensates and adjusts the water injection parameters according to the modified Darcy formula when the corrosion degree reaches the threshold; finally, the adaptive PID feedback control algorithm uses the gradient descent method with momentum term to dynamically adjust the proportional coefficient , the integral coefficient , and the differential coefficient , and by dynamically adjusting the learning rate η and setting a reasonable parameter adjustment frequency, the optimal valve opening adjustment amount is obtained through precise calculation of the flow control parameters.

[0014] In step S103, if the collected flow is inconsistent with the target flow, the opening degree of the flow regulating valve is calculated according to the set parameters.

[0015] In step S104, the actuator adjusts the flow valve opening degree according to the calculated flow valve opening degree. The actuator adjusts the flow regulating valve (grinding wheel sleeve type valve) in real time according to the control instruction output by the intelligent control table header, accurately adjusts the valve opening degree, and realizes precise control of the water injection flow parameter, ensuring that the water injection flow is stable within the target value range.

[0016] The method proposed in this application comprehensively considers factors such as temperature, pressure, and corrosion. By constructing an intelligent measurement and control system that integrates real-time multi-parameter monitoring, multi-model collaborative calculation, and adaptive dynamic control, it achieves comprehensive perception and precise processing of temperature and pressure changes and equipment corrosion during the water injection process. Complex algorithms are used to optimize and dynamically control water injection parameters in real time, thereby ensuring the stable and efficient operation of the high-pressure water injection process, significantly improving water injection quality, effectively extending the service life of water injection equipment, and reducing production costs and safety risks.

[0017] In some embodiments, the temperature effect model is used to correct the effect of temperature changes on injection flow calculation by establishing a functional relationship between the physical properties of injected water and temperature. The temperature effect model is a water dynamic viscosity calculation model:

[0018] Where a, b, and c are fitting coefficients, η is the dynamic viscosity of water, and T represents temperature (°C).

[0019] According to Poiseuille's law: , where Q is the volume flow rate, is the pressure difference before and after the pipe section, D is the inner diameter of the pipe (m), L is the length of the pipe section (m), The dynamic viscosity is used to eliminate the influence of temperature change on the injection flow calculation. The empirical correlation between the dynamic viscosity of water and temperature T is: , get traffic .

[0020] In some embodiments, the pressure control model is based on the principles of fluid mechanics, combined with the Bernoulli equation and the continuity equation , establish a dynamic relationship between pressure and flow and adjust the water injection flow according to pressure changes; The dynamic relationship between pressure and flow is established as:

[0021] in is the pressure at different positions (Pa), is the fluid density (kg / ), 、 is the flow velocity at different positions (m / s), g is the acceleration due to gravity, h is the height of the fluid relative to the reference horizontal plane (m), The cross-sectional area of ​​the pipe at different positions, in this application example, the subscripts 0 and 1 represent different positions respectively. In the specific example, the flow value that needs to be adjusted under the current pressure state is calculated based on the real-time collected pressure data (P0, P1), pipe parameters (A0, A1, h0, h1) and medium density. ( ), providing a basis for traffic control.

[0022] Adjust the water injection flow rate according to the pressure adjustment changes.

[0023] In some embodiments, the corrosion assessment and compensation model is used to assess the degree of equipment corrosion based on the material characteristics and service life of the equipment, and to compensate and adjust the water injection parameters when the degree of corrosion reaches a certain threshold; The corrosion assessment and compensation model is compensated and adjusted according to the modified Darcy formula:

[0024] in, Lambda is the friction coefficient, L is the pipe length, D is the inner diameter of the pipe, v is the flow rate, is the fluid density.

[0025] In a specific example, the corrosion data of the equipment on the pipeline is obtained by an ultrasonic thickness gauge to obtain the pipeline inner diameter data D(t). The corrosion degree of the equipment is evaluated by combining the material characteristics of the equipment and the service time t. When the corrosion degree reaches a certain threshold, the water injection parameters are compensated and adjusted. The adjustment is based on the Darcy formula Δ P = Lambda ， where Δ P Resistance loss (m), Lambda is the friction coefficient, L is the pipe length, D is the inner diameter of the pipe, v is the flow rate, is the fluid density. Friction coefficient Lambda From the Colebrook formula we can get is the Darcy friction coefficient (dimensionless), ε is the absolute roughness of the inner wall of the pipe (m), D is the pipe diameter (m), Re is the Reynolds number (dimensionless), and is defined as .

[0026] There is a lag between changes in pressure and flow. The present invention introduces an adaptive PID feedback control algorithm to dynamically adjust parameters in real time based on flow errors. In some embodiments, calculating the flow valve opening based on set parameters includes: Adaptive PID feedback control algorithm is used to dynamically adjust the proportional coefficient K according to the flow errorP , integral coefficient K i , differential coefficient K d .

[0027] In some embodiments, the adaptive PID feedback control algorithm adopts gradient descent method with momentum term for parameter adjustment, satisfying:

[0028] wherein j represents P, I, D three parameter types, represents the corresponding parameter, and a is a momentum factor, the value range is 0.8-0.95, used to preserve historical update direction information and avoid falling into local optimum, is a learning rate, controlling the parameter update step size. During the system running, represents the flow error, and the flow error , wherein is the target flow, is the actual measured flow, and the learning rate and parameter adjustment frequency are dynamically adjusted.

[0029] Step size determination: in the initial stage of system startup, the flow error is large, in order to speed up the convergence speed, a larger learning rate value (such as 0.3-0.5) is set in the embodiments of the application; as the error decreases, in order to avoid overshoot, the value is gradually reduced. At the same time, the is dynamically adjusted according to the error change rate, and the error change rate threshold δ is set, if |ΔE(k)|>δ, then η=η×0.9; if |ΔE(k)|≤δ, then η=η×1.1. Adjustment frequency determination: the adjustment frequency is related to the data acquisition frequency and the system response characteristics. Set to adjust once every n groups of data (n value is determined according to the actual response speed of the system, usually between 5-10). If the flow error is detected to be suddenly changed (such as the error exceeding the set threshold θ), the parameter adjustment is triggered immediately to quickly respond to the working condition change.

[0030] Different working condition adjustment strategy: Steady state: when the system is in steady state, the flow error is small and changes slowly, and the integral coefficient K i is mainly adjusted to eliminate steady state error. A small adjustment step size (such as Δ (k)=±0.01) is adopted, the proportional coefficient and the differential coefficient remain unchanged or are slightly adjusted (Δ (k)=Δ (k)=±0.005), to maintain the stability of the system.

[0031] Dynamic change conditions: When the system is disturbed by temperature, pressure fluctuations, etc., and the flow rate changes significantly, the proportional coefficient should be adjusted first. , quickly reduce the error. Set according to the error size The adjustment range, such as |E(k)|>10, Δ (k)=±0.2; 5<|E(k)|≤10, Δ (k)=±0.1. At the same time, adjust the differential coefficient appropriately , suppress system overshoot, The adjustment range is 0.3−0.5 times of the integral coefficient At this time, it remains unchanged to avoid integral saturation causing system response delay.

[0032] System startup or large-scale parameter adjustment conditions: After the system is started or the operator manually adjusts the water injection parameters, the flow error is usually large. In this case, it is first necessary to increase the proportional coefficient K P , making the system respond quickly, The adjustment range can be set to ±0.5; at the same time, in order to prevent excessive overshoot, a larger differential coefficient is introduced (e.g. ±0.3). Integral coefficient No adjustments are made at this stage. After the system is initially stable, adjustments will be made based on the steady-state error.

[0033] At the initial start-up of the water injection system, the operator sets the target pressure, flow rate and other parameters for water injection. The data acquisition module begins to collect temperature, pressure, corrosion and other data in real time and transmits it to the intelligent control header. The intelligent control header uses the core algorithm to process the collected data and calculate the valve opening adjustment amount of the water injection control parameter under the current state. The actuator adjusts the valve opening accordingly based on the control instructions output by the intelligent control header to achieve real-time control of the water injection process. During the water injection process, the data acquisition module continuously monitors the changes in various data in real time and continuously transmits the new data to the intelligent control header. The intelligent control header dynamically adjusts the water injection control parameters based on the latest data to ensure that the water injection process remains stable.

[0034] The method of the embodiment of the present application comprehensively considers multiple complex factors such as temperature, pressure, corrosion, etc., and uses precise algorithms to adjust water injection parameters in real time, effectively reducing water injection fluctuations caused by changes in external factors, significantly improving the stability of the water injection process, and ensuring the consistency of water injection quality.

[0035] The method of the embodiment of the present application, with the help of a corrosion assessment and compensation model, can promptly detect corrosion problems of equipment and reasonably adjust water injection parameters according to the degree of corrosion, thereby reducing damage to the equipment caused by corrosion, thereby extending the service life of the water injection equipment, reducing equipment maintenance and replacement costs, and extending the service life of the equipment.

[0036] The present application also provides a measurement and control system for stable high-pressure water injection, including: The data acquisition module is used to collect flow-related parameters of the pipeline section and relevant data during the water injection process. For example, temperature sensors are installed at the inlet and outlet of the pipeline and at key locations. The temperature sensors must be installed to avoid direct contact with the inner wall of the pipeline to prevent uneven local heating from affecting measurement accuracy. The measurement accuracy is ±0.5°C, which allows real-time fluid temperature acquisition. Pressure sensor groups are deployed at different heights and locations in the pipeline. The pressure difference is calculated by calculating the pressure sensor data at different locations. The pressure measurement accuracy meets the set standard. Ultrasonic thickness gauges are installed in areas prone to corrosion to regularly monitor pipeline thickness and obtain data related to the degree of equipment corrosion.

[0037] Install a grinding wheel sleeve flow control valve and flow sensor on the main water injection pipeline. The valve opening range is 0%-100%, with an adjustment accuracy of ±1% and a response time of no more than 2 seconds. Ensure that there is sufficient straight pipe length before and after the valve (generally 5-10 times the valve diameter) to ensure stable water flow and facilitate precise flow control.

[0038] Ensure a stable connection between the intelligent control meter and each sensor and actuator to ensure the accuracy and real-time data transmission. The intelligent control meter has a built-in core algorithm module that can receive and process multi-source data collected by sensors.

[0039] An intelligent control meter head is used to calculate a corrected flow value based on the flow-related parameters and water injection-related data using a temperature influence model, a pressure control model, and a corrosion assessment and compensation model; and If the collected flow rate is inconsistent with the target flow rate, the flow valve opening is calculated based on the set parameters; The actuator is regulated according to the flow valve opening calculated by the intelligent control meter.

[0040] The system runtime data acquisition module starts to collect data such as temperature, pressure, flow rate, pipe thickness in real time, and transmits them to the intelligent control table head. The intelligent control table head uses the temperature influence model to correct the parameters required for flow rate calculation according to the established function relationship between the physical properties of injected water and temperature (empirical correlation of water dynamic viscosity and temperature T); through the pressure control model, based on Bernoulli equation and continuity equation, combined with real-time collected pressure data, pipe parameters and fluid density, the flow rate value required to be adjusted under the current pressure state is calculated; using the corrosion evaluation and compensation model, according to the pipe inner diameter data obtained by the ultrasonic thickness gauge, combined with the material characteristics and service time of the equipment, the corrosion degree of the equipment is evaluated. Finally, according to the error between the corrected flow rate value and the target flow rate, the adjustment amount of the proportional coefficient , integral coefficient , and differential coefficient is calculated using the gradient descent method with momentum term, and then the optimal valve opening adjustment amount is obtained.

[0041] During the water injection process, the data acquisition module continuously monitors the changes of various data in real time, and transmits the new data to the intelligent control table head. The intelligent control table head uses the temperature influence model, pressure control model, and corrosion evaluation and compensation model in the core algorithm module to comprehensively process the data according to the latest data, and updates the corrected flow rate value in real time. At the same time, the error between the actual measured flow rate and the target flow rate, and the error change rate ΔE(k) are calculated.

[0042] According to the working condition of the system, the intelligent control table head uses different adjustment strategies to adjust the parameters of the adaptive PID feedback control algorithm.

[0043] The actuator adjusts the flow regulating valve in real time according to the control instruction output by the intelligent control table head, and accurately adjusts the valve opening. If the intelligent control table head calculates that the current actual flow rate is less than the target flow rate, a valve adjustment instruction is generated to increase the flow valve opening; if the actual flow rate is greater than the target flow rate, the valve opening is decreased until the collected flow rate and the target flow rate are consistent, realizing accurate control of the water injection flow rate parameter and ensuring that the water injection flow rate is stable within the target value range.

[0044] The entire measurement and control system of the embodiment has automatic data acquisition, processing and control capabilities. The operator only needs to set the initial parameters, and the system can automatically adjust the operating state according to the actual working condition, improving the production efficiency, reducing the manual operation intensity, and enhancing the intelligent level and reliability of the system.

[0045] It should be noted that in the embodiments of the present application, the terms "comprising", "including", or any other variant thereof are intended to cover a non-exclusive inclusion, so that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but can also include other elements that are not expressly listed or inherent to such process, method, article, or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0046] The above-mentioned sequence numbers of the embodiments of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0047] From the above description of the embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be realized by means of software and the necessary general hardware platform, of course, they can also be realized by hardware, but in many cases the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes a plurality of instructions for making a terminal (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) execute the methods described in the embodiments of the present application.

[0048] The embodiments of the present application are described above in combination with the drawings, but the present application is not limited to the above-mentioned specific embodiments, the above-mentioned specific embodiments are only illustrative, not restrictive, and those skilled in the art can make many forms under the inspiration of the present application without departing from the scope of the present application and the protection scope of the claims.

Claims

1. A method for measuring and controlling stable high-pressure water injection, characterized in that: include: Collect flow-related parameters of the pipe section; and, relevant data during the water injection process; Based on the flow-related parameters and relevant data during the water injection process, a temperature influence model, a pressure control model, and a corrosion assessment and compensation model are used to comprehensively calculate and obtain a corrected flow value; If the collected flow rate is inconsistent with the target flow rate, the flow valve opening is calculated based on the set parameters; The actuator is used to control the flow valve opening according to the calculation.

2. The method for measuring and controlling stable high-pressure water injection according to claim 1, characterized in that: The flow-related parameters include: Pipe section instantaneous flow value, cumulative flow value, temperature value, pressure value, and pipe section thickness; Relevant data during the water injection process include: flow rate, temperature, pressure and equipment corrosion data.

3. The method for measuring and controlling stable high-pressure water injection according to claim 1, wherein: The temperature effect model is used to correct the effect of temperature changes on the injection flow calculation by establishing a functional relationship between the physical properties of the injected water and the temperature. The temperature effect model is a water dynamic viscosity calculation model: Where a, b, and c are fitting coefficients, η is the dynamic viscosity of water, and T represents temperature in °C.

4. The method for measuring and controlling stable high-pressure water injection according to claim 3, characterized in that: The pressure control model is based on the principles of fluid mechanics and combined with the Bernoulli equation and the continuity equation , establish a dynamic relationship between pressure and flow and adjust the water injection flow according to pressure changes; The dynamic relationship between pressure and flow is established as: in, is the pressure at different positions, in Pa, is the fluid density, unit , 、 is the flow velocity at different positions, in m / s, The flow rate that needs to be adjusted under the current pressure state, the unit is , g is the acceleration due to gravity, h is the height of the fluid relative to the reference horizontal plane, 、 is the height of different locations, in m, is the cross-sectional area of ​​the pipe at different locations, unit ; Adjust the water injection flow rate according to the pressure adjustment changes.

5. The method for measuring and controlling stable high-pressure water injection according to claim 4, characterized in that: The corrosion assessment and compensation model is used to assess the degree of equipment corrosion based on the material characteristics and service life of the equipment. When the degree of corrosion reaches a certain threshold, the water injection parameters are compensated and adjusted. The corrosion assessment and compensation model is compensated and adjusted according to the modified Darcy formula: in, λ is the friction coefficient, L is the length of the pipeline, in m, D is the inner diameter of the pipe, in m, v is the flow velocity in m / s, is the fluid density in kg / m³.

6. The method for measuring and controlling stable high-pressure water injection according to claim 5, characterized in that: Calculating the flow regulating valve opening according to the set parameters includes: Adaptive PID feedback control algorithm is used to dynamically adjust the proportional coefficient according to the flow error , integral coefficient , differential coefficient .

7. The method for measuring and controlling stable high-pressure water injection according to claim 6, characterized in that: The adaptive PID feedback control algorithm uses a gradient descent method with a momentum term to adjust parameters, satisfying: Among them, j represents the three parameter types of P, I, and D. Indicates the corresponding parameters, represents the ordinal number, α is the momentum factor, is the learning rate, Indicates flow error.

8. A measurement and control system for stable high-pressure water injection, characterized in that: include: Data acquisition module, used to collect flow-related parameters of the pipe section; and, relevant data during the water injection process; An intelligent control meter head is used to calculate a corrected flow value based on the flow-related parameters and relevant data during the water injection process using a temperature influence model, a pressure control model, and a corrosion assessment and compensation model; as well as, If the collected flow rate is inconsistent with the target flow rate, the flow valve opening is calculated based on the set parameters; The actuator is regulated according to the flow valve opening calculated by the intelligent control meter.

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