A channeling testing device, evaluation method and evaluation device for a cement slurry for cementing

Abstract

This invention relates to the technical field of cementing, specifically to a cement slurry channeling testing device, evaluation method, and evaluation device. It solves the problems of low accuracy and poor sensitivity in cement slurry channeling monitoring. By developing a cement slurry channeling testing device based on resistivity response and establishing a high-pressure fluid channeling "liquid-electric" response characterization and evaluation method, the degree of cement slurry channeling can be accurately monitored, providing reference and guidance for anti-channeling cementing processes and the optimization of high-performance cement slurry systems.

Description

Technical Field

[0001] This invention relates to the technical field of cementing, and specifically to a cement slurry flow testing device, evaluation method, and evaluation device. Background Technology

[0002] During the setting process of cement slurry, the multiphase medium of the slurry gradually transforms from a "particle aggregate" to a "skeleton-pore structure." The cement gradually thickens and solidifies, causing a significant drop in the hydrostatic pressure of the annular slurry column. This leads to bottomhole pressure imbalance, inducing high-pressure oil, gas, and water intrusion into the annulus, seriously threatening cementing quality and the safety of oil and gas well operations. Therefore, accurate monitoring and evaluation of the cement slurry flow status are crucial measures to ensure the safe and long-term production of oil and gas wells. Summary of the Invention

[0003] The purpose of this invention is to provide at least one testing device, evaluation method, and evaluation device for cement slurry crossflow, which can at least solve the problems of low accuracy and poor sensitivity in monitoring cement slurry crossflow. By developing a cement slurry crossflow testing device based on resistivity response, and establishing a high-pressure fluid crossflow "liquid-electric" response characterization and evaluation method, the degree of cement slurry crossflow can be accurately monitored, providing reference and guidance for the optimization of anti-crossflow cementing processes and high-performance cement slurry systems.

[0004] In order to solve the technical problems existing in the prior art, this application proposes three technical solutions.

[0005] To address the aforementioned technical problems, in a first aspect, this application provides a device for testing the crossflow of cement slurry, comprising: a test wellbore, a resistance data acquisition system, a crossflow detection system, a liquid column pressure monitoring system, a formation fluid injection system, a temperature control system, a pressure control system, an upper vessel cover, a lower vessel cover, and a host computer; the test wellbore is a cylindrical structure open at both ends for containing the cement slurry to be tested; the lower vessel cover is detachably connected to the lower end of the test wellbore; the formation fluid injection system is connected to the test wellbore through the lower vessel cover for injecting formation fluid conforming to simulated conditions into the test wellbore; the temperature control system is installed on the side wall of the test wellbore for controlling the temperature of the cement slurry; the liquid column pressure... The monitoring system is installed on the side wall of the test wellbore to monitor the liquid column pressure data when the cement slurry loses weight; the resistance data acquisition system is installed on the side wall of the test wellbore to collect the resistivity of the cement slurry; the upper vessel cover is detachably connected to the upper end of the test wellbore; the flow detection system is connected to the test wellbore through the upper vessel cover to detect the flow data of the cement slurry; the pressure control system is connected to the inside of the test wellbore through the upper vessel cover to control the pressure inside the test wellbore; the host computer is communicatively connected to the resistance data acquisition system, the flow detection system, the liquid column pressure monitoring system, the formation fluid injection system, the temperature control system, and the pressure control system.

[0006] In some embodiments, the resistance data acquisition system includes: a resistivity acquisition controller and two contact electrodes. The two contact electrodes are connected to the resistance acquisition controller, with one end passing through the side wall of the test well and entering the test well, respectively for emitting and receiving current; the two contact electrodes are arranged vertically between each other; the resistivity acquisition controller is used to power one contact electrode and acquire the current value returned from the other contact electrode; the resistivity acquisition controller is also connected to the host computer and is used to send the resistivity determined based on the current value to the host computer.

[0007] In some embodiments, the temperature control system includes: a temperature controller, a heating device, and a temperature sensor; the temperature sensor is connected to the temperature controller and extends through the side wall of the test well into the test well to measure the current temperature inside the test well; the heating device is connected to the temperature controller and is arranged on the outer wall of the test well to heat the environment inside the test well; the temperature controller is connected to the host computer and is used to ensure that the ambient temperature of the test well meets the requirements through the heating device.

[0008] In some embodiments, the liquid column pressure monitoring system includes: a liquid column pressure acquisition device, a first pressure sensor, and a second pressure sensor; the first pressure sensor and the second pressure sensor are installed inside the test wellbore and are both connected to the liquid column pressure acquisition device; the first pressure sensor and the second pressure sensor are at different heights to collect the pressure of cement slurry at different heights; the liquid column pressure acquisition device is communicatively connected to the host computer to send the pressure data collected by the first pressure sensor and the second pressure sensor to the host computer.

[0009] In some embodiments, the formation fluid injection system includes: an injection pump and a formation fluid storage device; the injection pump is communicatively connected to the host computer, and one end of the injection pump is connected to the bottom of the test wellbore; the other end of the injection pump is connected to the formation fluid storage device, for injecting a specified formation fluid into the test wellbore according to the control of the host computer.

[0010] Secondly, this application proposes a method for evaluating the crossflow of fixed cement slurry, applicable to any of the fixed cement slurry crossflow testing devices described in the first aspect, comprising: acquiring preset formation parameter indicators; controlling the operation of a temperature control system, a pressure control system, and a formation fluid injection system according to the formation parameter indicators, so that the environment in the test wellbore meets the formation parameter indicators; acquiring performance parameters of the cement slurry to be evaluated in the test wellbore under different crossflow pressures through the resistance data acquisition system and the crossflow detection system; and evaluating the crossflow of the cement slurry to be evaluated based on the performance parameters.

[0011] In some embodiments, the performance parameters include resistivity and water flow rate; acquiring the performance parameters of the cement slurry to be evaluated in the test wellbore under different flow pressures through the resistance data acquisition system and the flow detection system includes: determining the resistance value of the cement slurry to be evaluated under different flow pressures based on the current data and voltage data collected by the resistance data acquisition system; determining the resistivity of the cement slurry to be evaluated under different flow pressures based on the resistance value of the cement slurry to be evaluated and the electrode parameters and arrangement of the contact electrodes of the resistance data acquisition system; and determining the water flow rate of the cement slurry to be evaluated under different flow pressures based on the flow detection system.

[0012] In some embodiments, evaluating the crossflow of the cement slurry to be evaluated based on the performance parameters includes: acquiring a crossflow pressure curve applied during the test; determining the resistivity variation of the cement slurry to be evaluated with crossflow pressure based on the crossflow pressure curve and the resistivity under different crossflow pressures; determining the flow rate variation of the cement slurry to be evaluated with crossflow pressure based on the crossflow pressure and the water crossflow rate; and evaluating the crossflow of the cement slurry to be evaluated based on the resistivity variation and the flow rate variation.

[0013] In some embodiments, the resistivity of the cement slurry to be evaluated is calculated using the following formula: In the formula, ρ is the resistivity of cement slurry, Ω·m; R is the resistance of cement slurry, Ω; DP is the electrode diameter, mm; LP is the electrode length, mm; and H is the distance between the two electrodes, mm.

[0014] Thirdly, this application proposes a device for evaluating the crossflow of cement slurry, comprising: a first acquisition module for acquiring preset formation parameter indicators; a first execution module for controlling a temperature control system, a pressure control system, and a formation fluid injection system to operate according to the formation parameter indicators, so that the environment in the test wellbore meets the formation parameter indicators; a second acquisition module for acquiring performance parameters of the cement slurry to be evaluated in the test wellbore under different crossflow pressures through a resistance data acquisition system and a crossflow detection system; and a first evaluation module for evaluating the crossflow of the cement slurry to be evaluated based on the performance parameters.

[0015] The embodiments of this application provide a technical solution that solves the problems of low accuracy and poor sensitivity in monitoring cement slurry crossflow. By developing a cement slurry crossflow testing device based on resistivity response, a "liquid-electric" response characterization and evaluation method for high-pressure fluid crossflow is established to accurately monitor the degree of cement slurry crossflow, providing reference and guidance for the optimization of anti-crossflow cementing processes and high-performance cement slurry systems. Attached Figure Description

[0016] 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.

[0017] Figure 1 This is a schematic diagram of the overall structure of a cement slurry channeling test device provided in an embodiment of this application;

[0018] Figure 2 This is a main flowchart of a method for evaluating the channeling of cement slurry provided in an embodiment of this application;

[0019] Figure 3 This is a schematic diagram of the structure of a cement slurry channeling evaluation device provided in an embodiment of this application;

[0020] Figure 4 This is a resistivity and liquid column pressure change curve provided in an embodiment of this application.

[0021] In the diagram: 100-Test wellbore, 101-Upper vessel cover, 102-Lower vessel cover, 200-Pressure control system, 300-Channel flow detection system, 400-Host computer, 501-Resistivity acquisition controller, 502-Contact electrode, 601-Temperature controller, 602-Temperature sensor, 603-Heating device, 700-Formation fluid injection system, 801-Pressure sensor, 802-Liquid column pressure acquisition device. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present 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 presented in the various embodiments of the present invention to enable the reader to better understand the present invention. However, the technical solutions claimed in the present invention can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0023] During the setting process of cement slurry, the multiphase medium of the slurry gradually transforms from a "particle aggregate" to a "skeleton-pore structure." The cement gradually thickens and solidifies, causing a significant drop in the hydrostatic pressure of the annular slurry column. This leads to bottomhole pressure imbalance, inducing high-pressure oil, gas, and water intrusion into the annulus, seriously threatening cementing quality and the safety of oil and gas well operations. Therefore, accurate monitoring and evaluation of the cement slurry flow status are crucial measures to ensure the safe and long-term production of oil and gas wells.

[0024] Due to the complex physicochemical hydration process of cement slurry, the static gel strength (SGS) is generally used to approximate the cement's solidification state. Early experiments found that air intrusion is most likely to occur when the SGS value is between 48-240 kPa. Therefore, based on the gel suspension theory, a series of cement slurry channeling testing devices have been developed, including cement slurry pore pressure testing devices and Chandler channeling simulation testing devices. A series of evaluation methods have also been established, including the channeling potential factor (FPF), performance response coefficient (SRN), comprehensive factor (CCGM), gelling loss coefficient (GELFL), and a series of subsequent improved methods. However, extensive practical experience shows that under conditions of high temperature, high pressure, and narrow annular space, static gel strength is insufficient to characterize the changes in static liquid column pressure caused by factors such as self-support, hydration heat release, chemical expansion and contraction, and reduced pore permeability, thus hindering accurate prediction of cement slurry channeling. Traditional monitoring devices and evaluation methods urgently need improvement.

[0025] Example 1:

[0026] like Figure 1 As shown, embodiments of the present invention relate to a cement slurry channeling testing device, comprising: a test wellbore 100, a resistance data acquisition system, a channeling detection system 300, a liquid column pressure monitoring system, a formation fluid injection system 700, a temperature control system, a pressure control system 200, an upper cap 101, a lower cap 102, and a host computer 400. The host computer 400 is communicatively connected to the resistance data acquisition system, the channeling detection system 300, the liquid column pressure monitoring system, the formation fluid injection system 700, the temperature control system, and the pressure control system 200.

[0027] The test well 100 is a cylindrical structure open at both ends, used to contain the cement slurry to be tested. The lower vessel cover 102 is detachably connected to the lower end of the test well 100. The upper vessel cover 101 is detachably connected to the upper end of the test well 100. The flow detection system 300 is connected to the test well 100 through the upper vessel cover 101 and is used to detect the flow data of the cement slurry. The pressure control system 200 is connected to the interior of the test well 100 through the upper vessel cover 101 and is used to control the pressure inside the test well 100.

[0028] Test wellbore 100: The body is 1500mm high and 60mm in diameter, used for injecting cement slurry. The inner wall is coated with an insulating layer with a heat resistance index of over 200℃. It can be made of inorganic-organic polymer base material. The upper cap 101 is connected to the flow detection system 300 and the pressure control system 200. The pressure control system 200 is a high-pressure pump to realize flow monitoring and pressurization inside the wellbore. The lower cap 102 is connected to the formation fluid injection system 700 to provide a fluid flow channel.

[0029] The 300-type flow detection system is primarily used to detect the flow rate of oil, gas, and water in cement ring systems. It includes a micro-fluid flow meter, a gas-liquid separator / dryer, a waste gas collector, pressure gauges, valves, and a high-precision electronic balance. The flow meter is mainly used for micro-fluid volumes, with a range of 0-100 mL / min and a testing accuracy of 0.001 mL / s. The high-precision electronic balance, using a Sartorius high-precision electronic balance with a range of 400 g, is used to calibrate and measure the liquid flow rate at the outlet during cement ring flow.

[0030] The formation fluid injection system 700 is connected to the test wellbore 100 via the lower cap 102, and is used to inject formation fluid conforming to simulated conditions into the test wellbore 100. The formation fluid injection system 700 includes an injection pump and a formation fluid storage device.

[0031] The injection pump is communicatively connected to the host computer 400, and one end of the injection pump is connected to the bottom of the test wellbore 100. The other end of the injection pump is connected to the formation fluid storage device, and is used to inject a specified formation fluid into the test wellbore 100 according to the control of the host computer 400.

[0032] Formation fluid injection system 700: The main component is a liquid injection pump, specifically a HAS-200HSB type dual-cylinder constant-speed and constant-pressure pump, used for quantitative injection of the displacement medium, providing a power source for the experiment. A continuous, pulse-free, dual-cylinder pump capable of constant speed and pressure operation is selected. This pump offers accurate metering and high precision, with an operating pressure of 0.001–30 MPa and a flow rate of 0.001–25 mL / min. It features pressure protection and upper / lower position limit protection. The pump head is made of 316L stainless steel and has suction, drainage, and pre-pressurization functions. The reversing valve is an electromagnetically controlled pneumatic valve. The pump chamber has a small volume and a short settling time. The pump is equipped with a communication port, allowing for both computer and manual operation.

[0033] The temperature control system is installed on the side wall of the test well 100 and is used to control the temperature of the cement slurry. The temperature control system includes: a temperature controller 601, a heating device 603, and a temperature sensor 602.

[0034] The temperature sensor 602 is connected to the temperature controller 601 and extends through the side wall of the test well 100 into the test well 100 to measure the current temperature inside the test well 100. The heating device 603 is connected to the temperature controller 601 and is arranged on the outer wall of the test well 100 to heat the environment inside the test well 100. The temperature controller 601 is connected to the host computer 400 and is used to ensure that the ambient temperature of the test well 100 meets the requirements through the heating device 603.

[0035] Temperature control system: The test wellbore is wrapped with a silicone heating jacket to simulate the formation temperature environment. The maximum operating temperature is 200℃, and the temperature control accuracy is ±1℃. The instrument has PID regulation and can perform programmed temperature rise. At the same time, it can automatically coordinate the temperature program changes according to the pressure rise and fall.

[0036] The liquid column pressure monitoring system is installed on the side wall of the test wellbore 100 and is used to monitor the liquid column pressure data when the cement slurry loses weight. The liquid column pressure monitoring system includes: a liquid column pressure acquisition unit 802, a first pressure sensor 801, and a second pressure sensor 801.

[0037] The first pressure sensor 801 and the second pressure sensor 801 are installed inside the test wellbore 100 and are both connected to the liquid column pressure acquisition device 802. The first pressure sensor 801 and the second pressure sensor 801 are located at different heights to collect the pressure of the cement slurry at different heights. The liquid column pressure acquisition device 802 is communicatively connected to the host computer 400 and is used to send the pressure data collected by the first pressure sensor 801 and the second pressure sensor 801 to the host computer 400.

[0038] Liquid column pressure data monitoring system: Primarily used to acquire liquid column pressure data during the weight loss process of cement slurry. It mainly consists of two sets of resistance sensors, with heights of 300mm and 1200mm respectively, a measuring range of 100kPa, an accuracy of +0.25%FS, a temperature resistance of 200℃, and a response time of less than 5ms. Since the testing process requires specific control over the moisture content and state of the cement slurry, we can monitor these parameters using liquid column pressure. Corresponding environmental changes can be implemented based on the liquid column pressure to improve the accuracy and reliability of the test results.

[0039] The resistance data acquisition system is installed on the side wall of the test well 100 and is used to collect the resistivity of the cement slurry. The resistance data acquisition system includes: a resistivity acquisition controller 501 and two contact electrodes 502.

[0040] Two contact electrodes 502 are connected to a resistance acquisition controller, with one end passing through the side wall of the test well 100 and entering the test well 100, respectively for emitting and receiving current; the two contact electrodes 502 are arranged vertically between each other; the resistivity acquisition controller 501 is used to power one contact electrode 502 and acquire the current value returned from the other contact electrode 502; the resistivity acquisition controller 501 is also connected to the host computer 400 and is used to send the resistivity determined according to the current value to the host computer 400.

[0041] Resistance data monitoring system: mainly used to acquire cement slurry electrical signals, mainly including two sets of contact electrodes 502, with heights of 600mm and 900mm respectively; the contact electrodes 502 are made of constantan wire, platinum-iridium alloy and kamma wire, with a diameter of 2mm and a penetration depth of 30mm into the inner wall of the well barrel; the linearity accuracy of the monitoring system is 0.05%; the resistance error is ±10%; the repeatability is 0.015mm; the temperature drift coefficient is 1.5ppm / ℃; the maximum allowable voltage is 60VDC / 5~20KΩ; the operating temperature is -5℃~+200℃.

[0042] In use such Figure 1When using the aforementioned flow measurement device, the cement slurry parameters to be tested are first acquired, including: cement slurry density, thickening time, and dosage of water loss reducing agent and anti-gas flow agent. Cement is then prepared according to these parameters. Next, formation parameters are acquired, including: formation ambient temperature, flow pressure, and formation water salinity. The parameters of the test wellbore 100 are adjusted according to these formation parameters. Then, the prepared cement slurry is injected into the test wellbore 100, and flow pressure and formation water are applied according to the formation parameters. The changes in cement slurry resistance and liquid column pressure are monitored, and resistance and liquid column pressure data are obtained to determine the flow state.

[0043] Compared with existing technologies, the test wellbore of this application can better simulate the downhole environment during cementing, and can better and more accurately measure the performance parameters of the cement slurry to be tested, providing reference and guidance for the optimization of anti-channeling cementing technology and high-performance cement slurry system.

[0044] Example 2:

[0045] Regarding the cross-current testing device proposed in Example 1, such as Figure 2 As shown, this application also proposes a cross-flow evaluation method compatible with the cross-flow testing device. The method is systematized in electronic production equipment, which can be a server, mobile terminal, computer, cloud platform, etc. The data processing function of the production equipment provided in this application embodiment can be implemented by the processor of the electronic production equipment calling program code, wherein the program code can be stored in a computer storage medium. The cross-flow evaluation method for fixed cement slurry includes...

[0046] Step S1: Obtain the preset formation parameter indices.

[0047] Step S2: Control the temperature control system, pressure control system, and formation fluid injection system according to the formation parameter indicators to ensure that the environment in the test wellbore meets the formation parameter indicators.

[0048] Step S3: Obtain the performance parameters of the cement slurry to be evaluated in the test wellbore under different tracing pressures through the resistance data acquisition system and the tracing detection system shown.

[0049] Since the cement slurry to be evaluated needs to undergo crossflow evaluation, the performance parameters of the cement slurry to be evaluated include: crossflow flow rate and resistivity under different crossflow pressures.

[0050] In some embodiments, step S3, "obtaining the performance parameters of the cement slurry to be evaluated in the test wellbore under different flow pressures through the resistance data acquisition system and the flow detection system shown," includes:

[0051] Step S31: Determine the resistance value of the cement slurry to be evaluated under different crossflow pressures based on the current data and voltage data collected by the resistance data acquisition system.

[0052] Step S32: Determine the resistivity of the cement slurry under different crossflow pressures based on the resistivity value of the cement slurry to be evaluated and the electrode parameters and arrangement of the contact electrodes of the resistance data acquisition system.

[0053] Due to such Figure 1 The two contact electrodes shown extend into the cement slurry, and the two contact electrodes are positioned with the electrodes facing each other. Therefore, the resistivity of the cement slurry under different crossflow pressures can be calculated using the following formula.

[0054]

[0055] In the formula, ρ is the resistivity of the cement slurry, Ω·m. R is the resistance of the cement slurry, Ω. DP is the electrode diameter, mm. LP is the electrode length, mm. H is the distance between the two electrodes, mm.

[0056] Step S33: Determine the water flow rate of the cement slurry to be evaluated under different flow pressures based on the flow detection system.

[0057] Step S4: Evaluate the flow of the cement slurry to be evaluated based on the performance parameters.

[0058] In some embodiments, step S4, "evaluating the flow of the cement slurry to be evaluated based on the performance parameters," includes:

[0059] Step S41: Obtain the crossflow pressure curve applied during the test.

[0060] Step S42: Determine the magnitude of the resistivity variation of the cement slurry to be evaluated with respect to the crossflow pressure based on the crossflow pressure curve and the resistivity under different crossflow pressures.

[0061] Step S43: Determine the variation range of the water flow rate of the cement slurry to be evaluated with the water flow pressure based on the crossflow pressure and the water flow rate.

[0062] Step S44: Evaluate the crossflow of the cement slurry to be evaluated based on the resistivity change range and the flow rate change range.

[0063] The resistivity and flow rate changes obtained in this application are shown in Table 1. The optimal fitting formula for the data in Table 1 is:

[0064]

[0065] In the formula, F is the water flow rate, mL; Δρ is the decrease in resistivity of cement slurry, %.

[0066]

[0067] Table 1

[0068] After obtaining the fitting formula for the resistivity change range and the flow rate change range, it is possible to judge whether the cement slurry to be evaluated can achieve the expected cementing effect well in practical applications based on the fitting formula, so as to provide reference and guidance for the optimization of anti-channeling cementing technology and high-performance cement slurry system.

[0069] Example 3:

[0070] Based on the foregoing embodiments, such as Figure 3 As shown, this application provides a device for evaluating the crossflow of cement slurry. The various modules and units included in the device can be implemented by a processor in a computer device; of course, they can also be implemented by specific logic circuits. In the implementation process, the processor can be a central processing unit (CPU), a microprocessor unit (MPU), a digital signal processor (DSP), or a field programmable gate array (FPGA), etc.

[0071] A device for evaluating the crossflow of cement slurry in well cementing includes: a first acquisition module 1, a first execution module 2, a second acquisition module 3, and a first evaluation module 4.

[0072] The first acquisition module 1 is used to acquire preset formation parameter indicators. The first execution module 2 is used to control the temperature control system, pressure control system, and formation fluid injection system according to the formation parameter indicators, so that the environment in the test wellbore meets the formation parameter indicators. The second acquisition module 3 is used to acquire the performance parameters of the cement slurry to be evaluated in the test wellbore under different crossflow pressures through the resistance data acquisition system and the crossflow detection system. The first evaluation module 4 is used to evaluate the crossflow of the cement slurry to be evaluated based on the performance parameters.

[0073] The modules in the aforementioned cement slurry crossflow evaluation device can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in the processor of the device in hardware form or independently of it, or stored in the memory of the processing device in software form, so that the processor can call and execute the operations corresponding to each module. It should be noted that the module division in this embodiment is illustrative and only represents a logical functional division; in actual implementation, there may be other division methods.

[0074] Example 4:

[0075] The testing device described in Example 1, in addition to accurately obtaining the mapping relationship between resistivity and crossflow flow rate as in Example 2, can also determine whether crossflow has occurred by measuring changes in liquid column pressure and resistivity under certain conditions where conditions are insufficient.

[0076] Under a constant crossflow pressure, resistivity and liquid column pressure were collected at different times. The collected data are shown in Table 2. Based on the data in Table 2, curves showing the changes in resistivity and liquid column pressure were plotted. Figure 4 As shown, through Figure 4 It can be observed that after the cement slurry is invaded by high-pressure fluid, the resistivity decreases rapidly and the liquid column pressure increases significantly, showing a significant real-time correlation between the two. Resistivity characterizes the rapid response and high sensitivity of the fluid cement slurry to crossflow.

[0077]

[0078] Table 2

[0079] It should be understood that the terms "mechanism," "device," "component," etc., used in this application are merely one method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they can be replaced by other expressions.

[0080] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention. In practical applications, the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification, and various changes can be made to them in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A device for testing the flow of cement slurry in well cementing, characterized in that, include: Test wellbore, resistance data acquisition system, crossflow detection system, liquid column pressure monitoring system, formation fluid injection system, temperature control system, pressure control system, upper vessel cover, lower vessel cover and host computer; The test well is a cylindrical structure with openings at both ends, used to contain the cement slurry to be tested; The lower vessel cover is detachably connected to the lower end of the test well barrel; The formation fluid injection system is connected to the test wellbore through the lower cap and is used to inject formation fluid that meets the simulation conditions into the test wellbore. The temperature control system is installed on the side wall of the test well to control the temperature of the cement slurry; The liquid column pressure monitoring system is installed on the side wall of the test wellbore and is used to monitor the liquid column pressure data when the cement slurry loses weight. The resistance data acquisition system is installed on the side wall of the test well and is used to collect the resistivity of the cement slurry. The upper vessel cover is detachably connected to the upper end of the test well barrel; The crossflow detection system is connected to the test well via the upper vessel cover and is used to detect the crossflow data of cement slurry; The pressure control system is connected to the inside of the test well via the upper cover and is used to control the pressure inside the test well. The host computer is communicatively connected to the resistance data acquisition system, the crossflow detection system, the liquid column pressure monitoring system, the formation fluid injection system, the temperature control system, and the pressure control system.

2. The apparatus according to claim 1, characterized in that, The resistance data acquisition system includes: a resistivity acquisition controller and two contact electrodes; The two contact electrodes are connected to the resistance acquisition controller, and one end of each electrode passes through the side wall of the test well and enters the test well, respectively for transmitting and receiving current. The two contact electrodes are arranged vertically between each other. The resistivity acquisition controller is used to power one contact electrode and acquire the current value returned from the other contact electrode. The resistivity acquisition controller is also connected to the host computer and is used to send the resistivity determined based on the current value to the host computer.

3. The apparatus according to claim 1, characterized in that, The temperature control system includes: a temperature controller, a heating device, and a temperature sensor; The temperature sensor is connected to the temperature controller and extends through the side wall of the test well into the test well to measure the current temperature inside the test well. The heating device is connected to the temperature controller and is arranged on the outer wall of the test well barrel to heat the environment inside the test well barrel. The temperature controller is connected to the host computer and is used to ensure that the ambient temperature of the test wellbore meets the requirements through the heating device.

4. The apparatus according to claim 1, characterized in that, The liquid column pressure monitoring system includes: a liquid column pressure acquisition unit, a first pressure sensor, and a second pressure sensor; The first pressure sensor and the second pressure sensor are installed inside the test wellbore and are both connected to the liquid column pressure acquisition device; The first pressure sensor and the second pressure sensor are at different heights to collect the pressure of the cement slurry at different heights; The liquid column pressure acquisition device is communicatively connected to the host computer and is used to send the pressure data collected by the first pressure sensor and the second pressure sensor to the host computer.

5. The apparatus according to claim 1, characterized in that, The formation fluid injection system includes: an injection pump and a formation fluid storage device; The injection pump is communicatively connected to the host computer, and one end of the injection pump is connected to the bottom of the test well. The other end of the injection pump is connected to the formation fluid storage device, and is used to inject a specified formation fluid into the test wellbore according to the control of the host computer.

6. A method for evaluating the cross-flow of fixed cement slurry, characterized in that, A device for testing the flow of fixed cement slurry as described in any one of claims 1-5, comprising: Obtain preset formation parameter indices; The temperature control system, pressure control system, and formation fluid injection system are controlled according to the formation parameter indicators to ensure that the environment in the test wellbore meets the formation parameter indicators. The performance parameters of the cement slurry to be evaluated in the test wellbore under different tracing pressures are obtained through the resistance data acquisition system and the tracing detection system shown. The cement slurry to be evaluated is subjected to crossflow evaluation based on the performance parameters.

7. The method according to claim 6, characterized in that, The performance parameters include resistivity and water crossflow rate; the resistance data acquisition system and the crossflow detection system obtained the performance parameters of the cement slurry to be evaluated in the test wellbore under different crossflow pressures, including: The resistance value of the cement slurry to be evaluated under different crossflow pressures is determined based on the current data and voltage data collected by the resistance data acquisition system. The resistivity of the cement slurry under different crossflow pressures is determined based on the resistivity value of the cement slurry to be evaluated and the electrode parameters and arrangement of the contact electrodes in the resistance data acquisition system. The water flow rate of the cement slurry to be evaluated under different flow pressures is determined based on the flow detection system.

8. The method according to claim 7, characterized in that, The evaluation of crossflow of the cement slurry to be evaluated based on the performance parameters includes: Obtain the crossflow pressure curve applied during the test; The resistivity variation of the cement slurry to be evaluated with respect to the crossflow pressure is determined based on the crossflow pressure curve and the resistivity under different crossflow pressures. The variation range of water flow rate with flow pressure of the cement slurry to be evaluated is determined based on the crossflow pressure and the water crossflow rate. The crossflow of the cement slurry to be evaluated is assessed based on the magnitude of the resistivity change and the magnitude of the flow rate change.

9. The method according to claim 7, characterized in that, The resistivity of the cement slurry to be evaluated is calculated using the following formula: In the formula, ρ is the resistivity of cement slurry, Ω·m; R is the resistance of cement slurry, Ω; DP is the electrode diameter, mm; LP is the electrode length, mm; and H is the distance between the two electrodes, mm.

10. A device for evaluating the flow of cement slurry in well cementing, characterized in that, include: The first acquisition module is used to acquire preset formation parameter indicators; The first execution module is used to control the temperature control system, the pressure control system and the formation fluid injection system to work according to the formation parameter indicators, so that the environment in the test wellbore meets the formation parameter indicators. The second acquisition module is used to acquire the performance parameters of the cement slurry to be evaluated in the test wellbore under different tracing pressures through the resistance data acquisition system and the tracing detection system shown. The first evaluation module is used to evaluate the crossflow of the cement slurry to be evaluated based on the performance parameters.

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