Well cementing truck liquid level and density synchronous control method based on model

Abstract

The invention discloses a model-based well cementation truck liquid level and density synchronous control method, and relates to the technical field of petroleum drilling, and the density synchronous control method comprises the following parts: A, a solid phase density calculation model and calculation method: (1) using a pneumatic conveying system to convey solid phase particles; a solid phase data calculation model, a mixing tank liquid quantity data model, a liquid level control model and a mixed liquid density calculation method are adopted, accurate model parameters are calculated through the calculation methods in combination with a data model analysis technology, and the liquid level control model is decomposed and coupled into a single closed-loop liquid level control method. A robust control steady-state approximation algorithm is adopted for liquid level model adjustment, finally the liquid level is within the control error of + / -5%, and then the problems that the liquid level is unstable in an automatic control mode of the well cementing truck, and the mixing tank overflows when cement is just added and the mixing tank is evacuated after filling is stopped when cement filling is finished are solved.

Description

Technical Field

[0001] The invention relates to the technical field of oil drilling, in particular to a model-based method for synchronously controlling the liquid level and density of a cementing vehicle. Background Art

[0002] Cementing trucks play a vital role in the oil drilling industry and are key equipment to ensure the sealing and safety of the wellhead. Cementing trucks inject cement slurry into the well wall through a high-pressure plunger pump. After a certain period of time, the cement slurry forms a solid protective layer in the wellbore to enhance the stability of the well wall and prevent the wellbore from collapsing. In addition to cement slurry, cementing trucks can also inject other types of slurries, such as clay slurry, polymer slurry, etc., to further seal the wellbore and reduce wellbore leakage. Cementing trucks are a special operation equipment in the oil industry. Its functional component assembly mainly consists of chassis, on-stage engine power system, hydraulic pump and motor system, control system, mixing tank, fracturing pump, high-energy mixer, manifold system, wiring harness and sensor, etc.

[0003] The normal operation process of cementing construction requires continuous and stable liquid supply to ensure that the liquid level and density are stable during the continuous construction process. Otherwise, unstable liquid level will cause vacuum or overflow, which will affect the quality of cementing operations and construction safety, and will also cause environmental pollution to the construction site. Therefore, automatic liquid level control and accurate density control of cementing trucks are very important in the construction process, which directly affects the quality and safety of construction operations.

[0004] At present, the traditional PID control method is the majority of automatic control methods for the liquid level and density of cementing trucks. The control model of this method often has abnormal control situations such as the mixing tank being emptied, overflowing, the density suddenly increasing to over-range, and directly becoming a clear water state, which seriously affects the on-site construction effect. In particular, when cement is suddenly added, liquid overflow often occurs. During the process of stopping cement addition, the phenomenon of emptying the tank occurs. It is very inconvenient for on-site operators to use, and they must manually take samples regularly to monitor the density effect. At this time, construction liquid leaks on the ground and outside the mixing tank. Summary of the invention

[0005] The object of the present invention is to provide a model-based method for synchronously controlling the liquid level and density of a cementing vehicle to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a model-based method for synchronously controlling the liquid level and density of a cementing vehicle, wherein the method for synchronously controlling the density comprises the following parts:

[0007] A. Solid phase density calculation model and calculation method: (1) using a pneumatic conveying system to transport solid phase particles, (2) using a solid phase particle meter to detect, and (3) setting the density value according to the system;

[0008] B. Data model and calculation method of liquid volume in mixing tank;

[0009] C. Liquid level control model;

[0010] D. Slurry density calculation model.

[0011] Preferably, the pneumatic conveying system in step A adopts a jet pump, which generates expansion force during the process of conveying solid particles. Pressure is generated only after passing through the ash particles during the ash conveying process. If the pressure is low or there is no pressure, it means that there is no ash output. At the same time, the superposition coefficient of the mixture entering the tank in the liquid level control is set to zero, and the pressure data at this time is not calculated using the input ash amount compensation.

[0012] Preferably, the solid phase particle meter detection in step A adopts microwave technology: when the solid phase particles are captured when passing through the microwave magnetic field of the pipeline during transportation, the system counts the solid phase particles, processes the signal according to the detected frequency, speed and number of particles, records the number of solid phase particles within a period of time, and after repeated measurement of accurate particles and ash amount, calibrates the corresponding coefficient and converts the ash amount within a certain period of time. Since the solid phase transportation process is a discrete transportation characteristic, the solid phase metering algorithm adopts a cumulative metering method to calculate the corresponding transported ash amount and the amount of ash entering the ground within the control period.

[0013] Preferably, in step A, the density value is set according to the system: after the density value is set, the butterfly valve opening size of the solid phase conveying speed is calculated by combining the current liquid volume in the mixing tank and the density value in the current mixing tank through the density mixing calculation model to control the density of the liquid in the mixing tank.

[0014] Preferably, the liquid volume in the mixing tank in step B is calculated using a dynamic calculation model, and the liquid entering the tank is measured by a jet pump flowmeter. The parameter is fitted as a linear function of time after calibration, and time integration is performed according to the flowmeter data during the calculation period to calculate the cumulative liquid volume, and then the net liquid volume after calibration is calculated based on the calibration coefficient.

[0015] Preferably, the solid phase entering the mixing tank in step B enters the mixing tank through a high-energy mixer, and the solubility ratio in water is obtained by fitting the model and calibrating it in the mixing tank, and the data function formula and volume coefficient of the solid phase volume and the amount of liquid entering the mixing tank are calculated, and the volume of the mixture instantly entering the mixing tank is calculated based on the calculated solubility ratio coefficient.

[0016] Preferably, the liquid level control model in step C: according to the two control parameters of liquid level and density input by the system, the controller uses the fitting function and the model coefficient to calculate the coupling coefficient, and at the same time the controller calculates the actual flow rate and solid phase volume of the injection pump in real time, and the controller performs decoupling calculation as the mixed liquid volume entering the tank speed, and according to the mixed liquid entering the tank speed and the current liquid level change rate coefficient, the robust control method is used to perform a segmented approximation algorithm to quickly adjust the injection pump and the ash lowering valve angle.

[0017] Preferably, the slurry density calculation model in step D: during the construction process, the jet pump flow is calculated through the fitting model to accurately calculate the amount of liquid entering the tank, and at the same time, the solid phase particle value is passed through the model fitting function to obtain the accurate solid phase volume, and the solid phase volume is calculated using the decoupling function to accurately calculate the instantaneous volume of the mixed liquid after fitting, and according to the density calculation formula, the mixing density of the current mixed liquid is accurately calculated and displayed visually.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention adopts a solid phase data calculation model, a liquid volume data model in a mixing tank, a liquid level control model, and a density calculation method for a mixed liquid. Through the above calculation methods, accurate model parameters are calculated respectively in combination with data model analysis technology, and the liquid level control model is decomposed and coupled into a single closed-loop liquid level control method. The liquid level model is adjusted using a steady-state approximation algorithm of robust control, and the liquid level is finally adjusted to within a control error of ±5%. This solves the problem of unstable liquid level in the automatic control mode of the cementing vehicle, avoids overflowing of the mixing tank when cement is just added, and avoids the phenomenon of evacuating the mixing tank after stopping cement filling at the end of cement filling. The density detection of the mixed liquid volume is stable to avoid sudden rise and fall. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of density synchronization control content of the present invention;

[0021] Figure 2 This is a flow chart of the cementing vehicle liquid level implementation of the present invention;

[0022] Figure 3 It is a schematic diagram of the slurry mixing process of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1: Please refer to Figure 1-Figure 3 The present invention provides a technical solution: a model-based method for synchronously controlling the liquid level and density of a cementing vehicle, wherein the method for synchronously controlling the density includes the following parts:

[0025] A. Solid phase density calculation model and calculation method:

[0026] (1) Use pneumatic conveying system to transport solid particles: The pneumatic conveying system uses a jet pump, which will generate expansion force when transporting solid particles. Pressure will only be generated after passing through the ash particles during the ash conveying process. If the pressure is low or there is no pressure, it means that there is no ash output. At the same time, the superposition coefficient of the mixture entering the tank in the liquid level control is set to zero. At this time, the pressure data is not calculated using the input ash amount compensation;

[0027] (2) The solid phase particle meter uses microwave technology to detect. When the solid phase particles are captured by the microwave magnetic field of the pipeline during transportation, the system counts the solid phase particles, processes the signal according to the detected frequency, speed, and number of particles, and records the number of solid phase particles within a period of time. After repeated measurement of accurate particles and ash volume, the corresponding coefficient is calibrated and the ash volume within a certain period of time is converted. Since the solid phase transportation process is a discrete transportation characteristic, the solid phase metering algorithm uses a cumulative metering method to calculate the corresponding ash volume transported and the ash volume entering the ground within the control period;

[0028] (3) According to the system set density value, combined with the current liquid volume in the mixing tank and the current density value in the mixing tank, the butterfly valve opening size of the solid phase conveying speed is calculated through the density mixing calculation model to control the density of the liquid in the mixing tank.

[0029] B. Data model and calculation method of liquid volume in mixing tank:

[0030] (1) Using the dynamic calculation model, the liquid entering the tank is measured by the jet pump flow meter. The parameter is calibrated and fitted into a linear function of time. The time is integrated according to the flow meter data within the calculation period to calculate the cumulative liquid volume, and then the net liquid volume after calibration is calculated according to the calibration coefficient;

[0031] (2) The solid phase entering the mixing tank enters the mixing tank through a high-energy mixer. In the mixing tank, the solubility ratio in water is obtained by fitting the model and calibrating it, and the data function formula and volume coefficient of the solid phase volume and the amount of liquid entering the mixing tank are calculated. The volume of the mixture that instantly enters the mixing tank is calculated based on the calculated solubility ratio coefficient.

[0032] C. Liquid level control model. According to the two control parameters of liquid level and density input by the system, the controller uses the fitting function and model coefficient to calculate the coupling coefficient. At the same time, the controller calculates the actual flow rate and solid volume of the injection pump in real time. The controller also performs decoupling calculation as the mixed liquid volume entering the tank speed. According to the mixed liquid entering the tank speed and the current liquid level change rate coefficient, the robust control method is used to perform a segmented approximation algorithm to quickly adjust the injection pump and the ash lowering valve angle.

[0033] D. Slurry density calculation model. During the construction process, the jet pump flow is calculated through the fitting model to accurately calculate the amount of liquid entering the tank. At the same time, the solid phase particle value is passed through the model fitting function to obtain the accurate solid phase volume. The solid phase volume is calculated using the decoupling function to accurately calculate the instantaneous volume of the mixed liquid after fitting. According to the density calculation formula, the mixing density of the current mixed liquid is accurately calculated and displayed visually.

[0034] Example 2: Please refer to Figure 1-Figure 3 The present invention provides a technical solution: a model-based cementing vehicle liquid level and density synchronous control method. The present invention makes corresponding improvements to the technical problems mentioned in the background technology. The cementing vehicle liquid level method includes the following parts:

[0035] First: calibrate the fitting coefficient of the jet pump flow meter model, continuously deliver water to the mixing tank through the jet pump of the whole machine, record the liquid flow change rate of the test tank when the liquid level in the liquid tank is stable, repeatedly measure 50 times and take the average of the jet pump displacement as the initial calibration coefficient of the jet pump flow meter, and perform online fitting coefficient calibration on the equipment in the later stage. The calibration method of the jet pump flow coefficient uses the liquid level of the mixing tank to measure the solvent in real time, and calibrates the flow of the jet pump according to the pressurized liquid volume discharged by the fracturing pump. The jet pump flow data is monitored in real time according to the calibration coefficient and calibrated according to the fitting coefficient to obtain the accurate liquid volume in the mixing tank.

[0036] Secondly: solid particles are measured by sensors. Within the normal pressure range of the conveying pipeline, the solid particle meter measures the solid particles passing through. The model parameters of particles and volume are fitted using machine learning technology to calculate the volume of solid particles within a certain period of time. This volume parameter is then substituted into the fitted volume model function of the solid particles in water to convert the volume of solid particles currently transported to the mixing tank in the liquid tank.

[0037] Next: the fitted volume data delivered by the jet pump and the volume of the solid phase particles after fitting conversion are combined and calculated to generate the mixed liquid flow parameters. The controller performs robust deviation control based on the set liquid level parameters and the actual liquid level rise rate parameters. The mixed liquid parameter is the coefficient of the liquid level deviation adjustment factor, which is adjusted by the actual liquid level change rate index and the liquid level stability index of the mixing tank.

[0038] Again: Based on the solid phase particle volume data and the jet pump flow volume data in the current time window and the current liquid level in the mixing tank, the online mixed liquid density value data is calculated through the fitting mathematical model, and the mixed liquid density value is transmitted to the display unit to display the density in real time, and the density change is displayed in the form of a visual curve.

[0039] Finally: the jet pump flow data after fitting and calibration, the volume data of solid phase transport particles after fitting, the current liquid level parameters, and the liquid density parameters in the mixing tank are saved in the database.

[0040] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0041] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A model-based method for synchronously controlling the liquid level and density of a cementing vehicle, characterized in that: The density synchronization control method includes the following parts: A. Solid phase density calculation model and calculation method: (1) using a pneumatic conveying system to transport solid phase particles, (2) using a solid phase particle meter to detect, and (3) setting the density value according to the system; B. Data model and calculation method of liquid volume in mixing tank; C. Liquid level control model; D. Slurry density calculation model.

2. A model-based method for synchronously controlling the level and density of a cementing vehicle according to claim 1, characterized in that: In step A, the pneumatic conveying system adopts a jet pump, which generates expansion force during the process of conveying solid particles. Pressure is generated only after passing through the ash particles during the ash conveying process. If the pressure is low or there is no pressure, it means that there is no ash output. At the same time, the superposition coefficient of the mixture entering the tank in the liquid level control is set to zero. At this time, the pressure data is not calculated using the input ash amount compensation.

3. The method for synchronously controlling the liquid level and density of a cementing vehicle based on a model according to claim 1, characterized in that: The solid phase particle meter detection in step A adopts microwave technology: after the solid phase particles are captured when passing through the microwave magnetic field of the pipeline during transportation, the system counts the solid phase particles, processes the signal according to the detected frequency, speed and number of particles, records the number of solid phase particles within a period of time, and after repeated measurement of accurate particles and ash amount, calibrates the corresponding coefficient and converts the ash amount within a certain period of time. Since the solid phase transportation process is a discrete transportation characteristic, the solid phase metering algorithm adopts a cumulative metering method to calculate the corresponding ash amount transported and the ash amount entering the ground within the control period.

4. The method for synchronously controlling the liquid level and density of a cementing vehicle based on a model according to claim 1, characterized in that: In step A, the density value is set according to the system: after the density value is set, the butterfly valve opening size of the solid phase conveying speed is calculated through the density mixing calculation model in combination with the current liquid volume in the mixing tank and the current density value in the mixing tank to control the density of the liquid in the mixing tank.

5. The method for synchronously controlling the liquid level and density of a cementing vehicle based on a model according to claim 1, characterized in that: In step B, the amount of liquid in the mixing tank is calculated using a dynamic calculation model. The liquid entering the tank is measured by a jet pump flow meter. The parameter is calibrated and fitted to a linear function of time. Time is integrated during the calculation cycle based on the flow meter data to calculate the cumulative liquid volume. The net liquid volume after calibration is then calculated based on the calibration coefficient.

6. The method for synchronously controlling the liquid level and density of a cementing vehicle based on a model according to claim 1, characterized in that: The solid phase entering the mixing tank in step B enters the mixing tank through a high-energy mixer, and the solubility ratio in water is calibrated by fitting a model in the mixing tank, and the data function formula and volume coefficient of the solid phase volume and the liquid volume entering the mixing tank are calculated, and the volume of the mixture instantly entering the mixing tank is calculated based on the calculated solubility ratio coefficient.

7. The method for synchronously controlling the liquid level and density of a cementing vehicle based on a model according to claim 1, characterized in that: The liquid level control model in step C: according to the two control parameters of liquid level and density input by the system, the controller uses the fitting function and the model coefficient to calculate the coupling coefficient, and at the same time the controller calculates the actual flow rate and solid phase volume of the injection pump in real time, and the controller performs decoupling calculation as the mixed liquid volume entering the tank speed, and according to the mixed liquid entering the tank speed and the current liquid level change rate coefficient, the robust control method is used to perform a segmented approximation algorithm to quickly adjust the injection pump and the ash lowering valve angle.

8. The method for synchronously controlling the liquid level and density of a cementing vehicle based on a model according to claim 1, characterized in that: The slurry density calculation model in step D: during the construction process, the jet pump flow is calculated through the fitting model to accurately calculate the amount of liquid entering the tank. At the same time, the solid phase particle value is passed through the model fitting function to obtain the accurate solid phase volume. The solid phase volume is calculated using the decoupling function to accurately calculate the instantaneous volume of the mixed liquid after fitting. According to the density calculation formula, the mixing density of the current mixed liquid is accurately calculated and displayed visually.

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