Device and method for testing pressure transfer rate in whole hydration process of oil-gas well cement paste

Abstract

The invention provides an oil-gas well cement paste hydration whole process pressure transfer rate testing device and method, and the device comprises a sealed testing slurry cup, a cement paste heating system, a pressurization medium temperature and pressure control system, a cement paste temperature control system, and a cement paste lower end pressure monitoring system. The cement paste heating system is connected with the sealing test paste cup through the second connector, the first valve and the first connector in sequence, and the pressurizing medium temperature and pressure control system is connected with the sealing test paste cup through the third connector, the second valve and the upper end hydraulic connector in sequence. A sensor of the cement paste temperature control system and a sensor of the cement paste lower end pressure monitoring system collect data of the testing device, and the sensor of the cement paste temperature control system and the sensor of the cement paste lower end pressure monitoring system are both connected with a computer control collection system. According to the method, the well cementation site construction design can be guided, the fine pressure control well cementation and prestress well cementation processes are optimized, and the gas channeling risk can be effectively prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas well cementing, and particularly relates to a device and a method for testing the pressure transmission rate during the whole hydration process of oil and gas well cement slurry. Background Art

[0002] With the development of the oil industry, from the initial shallow cementing at a depth of several hundred meters to the current ultra-deep cementing at a depth of several thousand or even tens of thousands of meters, higher requirements are put forward for the cementing technology. In order to improve the cementing quality and alleviate the problem of annulus pressure in deep shale gas, industry experts have proposed a cementing technology of applying backpressure in the annulus. After the cement slurry is displaced in place, a certain pressure is applied to the upper end face of the cement slurry to control the slurry column pressure, alleviating the gas channeling problem caused by the loss of weight of the cement slurry. However, after the cement slurry is injected into the annulus, it undergoes a hydration and setting process from liquid state, liquid-plastic state to solid state. During this process, whether the cement slurry column can completely transmit the upper end pressure and how much pressure it can transmit are currently lacking relevant testing and quantitative evaluation methods. If the pressure transmission effect of the cement slurry column under field conditions can be tested and quantitatively evaluated indoors, it will be able to effectively predict the change of the liquid column pressure in the target section, avoid the gas channeling risk, and guide the optimization of the cementing anti-channeling process, the formation of the anti-channeling cement slurry system, and the design of cement slurry anti-channeling materials, which is of great significance for cementing anti-channeling.

[0003] At present, some patents have explored the testing of the pressure transmission effect during the hydration process of oil well cement. For example: Liu Kaiqiang. Evaluation device and method for static liquid column pressure and pressure transmission ability during the hardening of cement slurry for well cementing, with the publication number CN115263277A. This device can test the pressure transmission ability of cement slurry under certain temperature and pressure conditions, but the test medium used is high-pressure nitrogen, which will affect the hydration process of cement slurry during the experiment and can no longer meet the on-site engineering conditions of ultra-deep wells under high temperature and high pressure. Liu Kaiqiang. Evaluation method for the pressure transmission efficiency of well cementing cement slurry during the solidification process, with the publication number CN116624139A. Using nitrogen as the test medium will affect the test results. The pressure transmission efficiency proposed in the patent is only the pressure transmission efficiency of cement slurry in laboratory experiments and has no connection with the field, so it is impossible to infer the pressure transmission efficiency of the on-site cement slurry column. Guo Xiaoyang. Device and method for measuring the weight loss of cement slurry in the annulus of well cementing: publication number CN102392634B, inventor Tao Qian. Evaluation of the pressure loss and gas channeling prevention ability of a cement slurry: publication number CN107843721B, inventor Li Qian. A monitoring system and method for the weight loss process of annulus cement slurry: publication number CN112465089B. The above several devices only measure the static liquid column pressure during the solidification process of the cement slurry column, reflecting the weight loss law of the cement slurry. Related patents established in the early stage, such as the inventor Liu Jian. A device and method for testing the dynamic permeability during the solidification process of oil and gas well cement slurry, with the publication number CN114279936B, are aimed at testing the change in the basic physical property of permeability of the cement stone. The pressure transmission efficiency of the cement slurry can be reflected indirectly through the permeability, but the pressure transmission efficiency of the cement slurry column cannot be quantified, and it has no practical value for the field.

[0004] There is an urgent need for a dynamic testing device and method for the pressure transmission rate of a cement slurry column, which can meet the requirements of testing the change in the pressure transmission rate during the entire hydration process of cement slurry under high temperature and high pressure conditions, deducing and calculating the pressure transmission rate of the on-site cement slurry column, and ensuring that the test medium does not affect the hydration of the cement slurry and the formation of its internal structure during the test process, thereby guaranteeing the accuracy of the test results. Summary of the Invention

[0005] The purpose of the present invention is to solve the defects existing in the above-mentioned prior art, and provide a device and method for testing the pressure transmission rate during the entire hydration process of oil and gas well cement slurry, which can continuously test the change in the pressure transmission rate during the entire hydration process of cement slurry at the on-site temperature and pressure, and the selected test medium is the mixing water, which does not affect the hydration of the cement slurry and the formation of its internal structure.

[0006] The present invention adopts the following technical solutions: An apparatus for testing the pressure transmission rate during the entire hydration process of oil and gas well cement slurry, comprising a sealed test slurry cup, a cement slurry heating system, a pressure medium temperature and pressure control system, a cement slurry temperature control system, and a cement slurry lower-end pressure monitoring system. The cement slurry heating system is sequentially connected to the sealed test slurry cup through a second interface, a first valve, and a first interface. The pressure medium temperature and pressure control system is sequentially connected to the sealed test slurry cup through a third interface, a second valve, and an upper hydraulic interface. The cement slurry temperature control system and the cement slurry lower-end pressure monitoring system respectively collect data of the test apparatus, and the sensors of the cement slurry temperature control system and the cement slurry lower-end pressure monitoring system are both connected to a computer control and acquisition system.

[0007] Further, the sealed test slurry cup is divided into a test inner cylinder and a test outer cylinder. The test inner cylinder contains the cement slurry to be tested, and a heat-conducting medium is contained in the annular space between the test outer cylinder and the test inner cylinder. A test top cover and a test bottom base are respectively fixed on both sides of the test outer cylinder through screws, and the test top cover and the test bottom base are respectively sealed with the test outer cylinder and the test inner cylinder through sealing rubber rings; the annulus between the test inner cylinder and the test outer cylinder is connected to a nitrogen cylinder through an upper annulus interface, a three-way valve III, a three-way valve I, and a four-way valve. The annulus is connected to a vent valve II through an upper annulus interface and a three-way valve III. The upper end of the annulus is connected to the upper end of a heat-conducting medium supply container through an upper annulus interface, a three-way valve III, a three-way valve I, and a three-way valve II. The bottom end of the annulus between the test inner cylinder and the test outer cylinder is connected to the lower end of the heat-conducting medium supply container through a lower annulus interface and a third valve. The heat-conducting medium supply container is connected to a vent valve I through a three-way valve II.

[0008] Further, the first heating jacket is sleeved on the test outer cylinder.

[0009] Further, the cement slurry heating system includes a sealed heating slurry cup, a heating device, and a transmission device; The sealed heating slurry cup includes a heating base, a heating kettle body, a heating top cover, a sealed bearing, a sealing cover, and a magnetic drive paddle. The heating base and the heating top cover are respectively connected to the heating kettle body through threads, and both the heating base and the heating top cover are sealed with the heating kettle body through sealing rings. The sealing cover is connected to the heating top cover through a thread. A sealed bearing is installed in the middle of the heating top cover, and the magnetic drive paddle is installed on the sealed bearing. The upper end of the sealed heating slurry cup is connected to a nitrogen cylinder through a heating air pressure interface, a first pressure reducing valve, a four-way valve.

[0010] The heating device includes a second heating jacket sleeved outside the heating kettle body, a temperature sensor d installed on the heating kettle body, and a temperature sensor c installed on the second heating jacket; the signal output ends of the temperature sensor c and the temperature sensor d, as well as the second heating jacket, are respectively connected to a temperature control device, and the signal output end of the temperature control device is connected to a computer control and acquisition system.

[0011] The transmission device includes a motor, an electric pulley, and a magnetic drive pulley. The magnetic drive pulley is installed outside the sealing cover. The magnetic drive pulley is connected to the electric pulley through a belt. The magnetic drive pulley drives the magnetic drive paddle to rotate through magnetic force. The electric pulley is connected to the motor through a transmission shaft, and the motor is connected to a computer control and acquisition system.

[0012] Further, the pressurized medium temperature and pressure control system includes a sealed pressurized slurry cup, a medium heating device, and a pressurized medium pressure control device; The sealed pressurized slurry cup includes a pressurized top cover, a pressurized kettle body, and a pressurized base. The pressurized top cover and the pressurized base are respectively connected to the pressurized kettle body through threads, and the pressurized top cover and the pressurized base are respectively sealed with the pressurized kettle body through sealing rubber rings.

[0013] The medium heating device includes a third heating sleeve sleeved on the pressurized kettle body, a temperature sensor f installed on the third heating sleeve, and a temperature sensor e installed on the pressurized top cover. The signal output ends of the temperature sensor e, the temperature sensor f, and the third heating sleeve are respectively connected to a temperature control device, and the signal output end of the temperature control device is connected to the computer control and acquisition system.

[0014] The pressurized medium pressure control device includes a fourth interface, a pressurized medium supply container, an upper end pressurizing device, an upper end pressure sensor, and a fifth valve. The fourth interface is connected to the upper end pressurizing device through a hydraulic pipeline, and a fifth valve is installed on this hydraulic pipeline. An upper end pressure sensor is installed at the outlet of the upper end pressurizing device. The upper end pressurizing device is connected to the pressurized medium supply container through a hydraulic pipeline and a sixth valve. The pressurized medium supply container is filled with mixing water.

[0015] Further, the cement slurry temperature control system includes a first heating sleeve sleeved on the test outer cylinder, a temperature sensor b installed on the first heating sleeve, a temperature sensor a installed on the test top cover, a heat transfer medium supply container, and a temperature control device. The signal output ends of the temperature sensor a, the temperature sensor b, and the first heating sleeve are respectively connected to the temperature control device, and the signal output end of the temperature control device is connected to the computer control and acquisition system.

[0016] The upper end of the heat transfer medium supply container is connected to a nitrogen cylinder through a gas pipeline, a three-way valve II, a three-way valve I, and a four-way valve; the heat transfer medium supply container is also connected to a vent valve I through a gas pipeline and a three-way valve II.

[0017] Further, the heat transfer medium supply container is filled with a heat transfer medium, and the initial boiling point of the heat transfer medium is 320 °C, the flash point is 255 °C, and the pour point is -15 °C.

[0018] Further, the lower end pressure monitoring system of the cement slurry includes a lower end pressure measurement interface, a fourth valve, a lower end pressure sensor, and a lower end micro-leakage container; The lower pressure measurement interface contains a filter element inside. The lower pressure measurement interface is connected to the lower micro-leakage container through a hydraulic pipeline. A fourth valve is also installed on the hydraulic pipeline. The lower micro-leakage container is processed to leak at a micro-flow rate of 0.001~0.01 cm 3 / s within a certain pressure range. The lower micro-leakage container is filled with mixing water. The signal acquisition end of the lower pressure sensor is connected to the lower micro-leakage container, and the signal output end of the lower pressure sensor is connected to the computer control acquisition system.

[0019] During the cement slurry test, both the upper and lower ends are in contact with the mixing water, which has no impact on the hydration and structure formation of the cement slurry. The computer control system records the change process and current values of curves such as the temperature and pressure of the cement slurry and the pressurizing medium in real time.

[0020] The test method of the above-mentioned device for testing the pressure transmission rate during the whole process of oil and gas well cement slurry hydration includes the following steps in sequence: (1). Seal the test base and the test top cover with the test inner cylinder through sealing rubber rings respectively, and install them on the test outer cylinder through screws.

[0021] (2). After sealing the pressurizing base and the pressurizing kettle body with a sealing rubber ring and connecting them by threads, connect the upper hydraulic interface to the test top cover by threads. The upper hydraulic interface is connected to the third interface through a hydraulic pipeline and a second valve. Connect the third interface to the pressurizing base by threads. Close the second valve, fill the pressurizing kettle body with mixing water, connect the pressurizing top cover to the pressurizing kettle body by threads, and seal it with a sealing ring; (3). Seal the heating base and the heating kettle body with a sealing rubber ring and connect them by threads. Connect the first interface to the test top cover by threads. The first interface is connected to the second interface through a hydraulic pipeline and a first valve. Connect the second interface to the heating base by threads. Close the first valve, install the magnetic drive impeller in the heating kettle body, pour the prepared cement slurry into the heating kettle body, connect the heating top cover to the heating kettle body by threads, and seal it with a sealing ring. Install the sealing bearing on the heating top cover through a buckle. The sealing bearing is sealed with the heating top cover and the magnetic drive impeller through a sealing ring. Connect the sealing cover to the heating top cover by threads and seal it with a sealing ring. Install the magnetic drive pulley outside the sealing cover and connect it to the electric pulley through a belt; (4). Coat the surface of temperature sensor a with a layer of high-temperature resistant lubricating oil, insert it into the test inner cylinder, and tightly connect it to the test top cover through threads and sealing rings. Temperature sensor a is in direct contact with the cement slurry to be tested during the test. Connect temperature sensor b to the first heating sleeve, insert temperature sensor c into the heating kettle body and tightly connect it to the heating kettle body through threads, connect temperature sensor d to the second heating sleeve, insert temperature sensor e into the pressurizing medium and tightly connect it to the pressurizing top cover through threads and sealing rings, connect temperature sensor f to the third heating sleeve, and connect the temperature control device to the first heating sleeve, the second heating sleeve, the third heating sleeve, temperature sensor a, temperature sensor b, temperature sensor c, temperature sensor d, temperature sensor e, temperature sensor f, and the computer control acquisition system respectively through data lines; (5). Fill the heat-conducting medium supply container with heat-conducting medium. Connect the heat-conducting medium supply container to the four-way valve through the air pressure pipeline via three-way valve II and three-way valve I. Connect the heat-conducting medium supply container to the atmosphere through the air pressure pipeline via three-way valve II and vent valve I. Connect the upper air pressure interface to the four-way valve through the air pressure pipeline via pressure reducing valve II. The upper air pressure interface is connected to the test top cover through threads. Connect the upper annulus interface to the four-way valve through the air pressure pipeline via three-way valve III and three-way valve I. The upper annulus interface is connected to the atmosphere through three-way valve III and vent valve II. The upper annulus interface is connected to the test top cover through threads. Connect the heating air pressure interface to the four-way valve through the air pressure pipeline via the first pressure reducing valve. The heating air pressure interface is connected to the heating top cover through threads. Connect the lower annulus interface to the heat-conducting medium supply container through a pipeline via the third valve. The lower annulus interface is connected to the test base through threads. Connect the four-way valve to the nitrogen cylinder through the air pressure pipeline.

[0022] (6). Connect one end of the lower pressure sensor to the lower micro-leakage container and the other end to the computer control acquisition system. Connect one end of the lower micro-leakage container to the lower pressure measurement interface through a hydraulic pipeline via the fourth valve, and the other end to the atmosphere through a leakage pipeline. Connect the lower pressure measurement interface to the test base through threads.

[0023] (7). Connect one end of the upper pressure sensor to the upper pressurizing device and the other end to the computer control acquisition system. Connect one end of the upper pressurizing device to the fourth interface through a hydraulic pipeline via the fifth valve, and the other end to the pressurizing medium supply container through a hydraulic pipeline via the sixth valve. Connect the fourth interface to the pressurizing top cover through threads.

[0024] (8). Before the experiment, ensure that all valves are closed. Open the nitrogen cylinder, four-way valve, three-way valve I, three-way valve II, third valve, three-way valve III, and vent valve II. Fill the annular space formed between the test outer cylinder and the test inner cylinder with heat-conducting medium from the heat-conducting medium supply container. Close three-way valve III and vent valve II, and open vent valve I.

[0025] (9). Open the fifth valve and the sixth valve, start the upper pressurizing device, set the target pressure, and use the upper pressurizing device to continuously and evenly press the upper end of the pressurizing medium through the fourth interface until the target pressure is reached and the target pressure is maintained. (10). Open the pressure dividing valve I, use the pressure dividing valve I to control the upper end pressure of the cement slurry to be heated during the heating process through the heating air pressure interface, open the pressure dividing valve II, and use the pressure dividing valve II to control the pressure inside the test inner cylinder through the upper end air pressure interface. (11). Start the motor through the computer-controlled acquisition system and use the electric pulley and the magnetic drive pulley to control the magnetic drive blade to stir the cement slurry at a rotational speed of 1505 r / min. (12). Open the temperature control device, preset the heating temperature and the heating rate, respectively control the first heating jacket, the second heating jacket, and the third heating jacket to heat the test inner cylinder, the cement slurry to be heated, and the pressurizing medium, and open the computer-controlled acquisition system to record the temperatures inside the test inner cylinder, the cement slurry to be heated, and the heating medium.

[0026] (13). After the temperature of the cement slurry to be heated rises to the preset heating temperature, open the first valve. Through the pressure difference, the cement slurry to be heated is pressed from the heating kettle body into the test inner cylinder. Open the second valve, use the upper pressurizing device to control the upper end pressure of the cement slurry to be tested to be P1 through the pressurizing medium, open the fourth valve, start the lower end pressure sensor, and use the lower end micro-leakage control container to control the mixing water to flow out at a constant micro-flow rate of 0.001~0.01 cm 3 / s.

[0027] (14). Record the changes in the upper and lower end pressures of the cement slurry to be tested through the computer-controlled acquisition system.

[0028] (15). After the experiment is completed, the computer-controlled acquisition system saves the experimental data, closes the temperature control device. After the experimental device cools down to room temperature, use the upper pressurizing device to release the upper end pressure of the cement slurry to be tested, close the upper pressurizing device, the fifth valve, and the fourth valve, open the three-way valve III, press the heat transfer medium into the heat transfer medium supply container, close the nitrogen cylinder. After the air pressure of the device is completely released, close all valves, remove the pipelines of each device and the monitoring system, remove the test base and the test top cover, take out the test sample, and clean the first interface, the first valve, the second interface, the heating base, the heating kettle body, and the heating top cover.

[0029] Advantages of the present invention: (1). The present invention takes the cement slurry as the research object, observes the changes in the upper and lower end pressures of the cement slurry by monitoring the micro-seepage process of the mixing water in the cement slurry during the whole hydration process of the cement slurry under temperature and pressure, without affecting the hydration process of the cement slurry and the formation of its internal structure.

[0030] (2). The present invention monitors the temperature change during the hydration process of the cement slurry, monitors the heat release during the hydration of the cement slurry during the test, and assists in the test and interpretation of the pressure transmission rate.

[0031] (3). The present invention effectively tests the change of the pressure transmission rate during the whole process of cement slurry hydration and deduces and calculates the pressure transmission rate of the on-site cement slurry column, which can guide the construction design of the cementing site, optimize the fine pressure control cementing and prestressed cementing process technologies, and can effectively prevent the risk of gas channeling. Description of the Drawings

[0032] Figure 1 It is a schematic structural diagram of the device for testing the pressure transmission rate during the whole process of cement slurry hydration in oil and gas wells of the present invention; Figure 2 It is a schematic diagram of the test result of the pressure transmission rate during the whole process of cement slurry hydration at 60 °C in Example 1; Figure 3 It is a schematic diagram of the test result of the pressure transmission rate during the whole process of cement slurry hydration at 120 °C in Example 2.

[0033] In the figure: 1 - test base, 2 - test outer cylinder, 3 - test inner cylinder, 4 - cement slurry to be tested, 5 - first heating jacket, 6 - test top cover, 7 - first interface, 8 - first valve, 9 - second interface, 10 - heating base, 11 - heating kettle body, 12 - second heating jacket, 13 - cement slurry to be heated, 14 - motor, 15 - electric pulley, 16 - heating top cover, 17 - sealed bearing, 18 - magnetic drive pulley, 19 - sealing cover, 20 - magnetic drive impeller, 21 - heating air pressure interface, 22 - temperature sensor c, 23 - temperature sensor d, 24 - pressurizing top cover, 25 - third heating jacket, 26 - pressurizing kettle body, 27 - pressurizing medium, 28 - pressurizing base, 29 - third interface, 30 - second valve, 31 - upper end hydraulic interface, 32 - upper end air pressure interface, 33 - temperature sensor a, 34 - annulus upper end interface, 35 - temperature sensor b, 36 - annulus lower end interface, 37 - lower end pressure measurement interface, 38 - fourth interface, 39 - temperature sensor e, 40 - temperature sensor f, 41 - first pressure reducing valve, 42 - four-way valve, 43 - three-way valve Ⅰ, 44 - vent valve Ⅰ, 45 - three-way valve Ⅱ, 46 - pressure reducing valve Ⅱ, 47 - three-way valve Ⅲ, 48 - vent valve Ⅱ, 49 - heat transfer medium supply container, 50 - third valve, 51 - fourth valve, 52 - lower end pressure sensor, 53 - lower end micro-leakage container, 54 - pressurizing medium supply container, 55 - temperature control device, 56 - nitrogen cylinder, 57 - fifth valve, 58 - upper end pressurizing device, 59 - sixth valve, 60 - computer control and acquisition system, 61 - upper end pressure sensor. Detailed Embodiments

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the present invention will be described clearly and completely below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0035] Improvements to the test method of the present invention: In the experiment, the micro-seepage method of the slurry water is used to monitor the change process of the upper and lower end pressures during the entire hydration process of the cement slurry. The test medium is the slurry water, which seeps through the cement slurry at a weak flow rate without affecting the hydration process of the cement slurry and the formation of its internal structure; by monitoring the temperature change during the hydration process of the cement slurry, the heat release during the hydration of the cement slurry during the test is monitored, which assists in the test and interpretation of the pressure transmission rate, and provides a reference basis for understanding the hydration process of the cement slurry. Improvements to the calculation method: The experiment takes the cement slurry as the research object, simulates the hydration and solidification process of the cement slurry under actual working conditions, monitors the real-time change of the upper and lower end pressures of the cement slurry column through the micro-seepage method of the slurry water, and derives and calculates the pressure transmission rate of the on-site cement slurry column based on the on-site monitoring data.

[0036] The indoor pressure transmission rate calculation method of the pressure transmission rate testing device for the entire hydration process of oil and gas well cement slurry: Wherein: is the pressure transmission rate of the cement slurry column calculated according to the indoor test; is the upper end pressure of the indoor test cement slurry column; is the lower end pressure of the indoor test cement slurry column.

[0037] The on-site cement slurry column pressure transmission rate derivation and calculation method of the pressure transmission rate testing device for the entire hydration process of oil and gas well cement slurry: Wherein: is the on-site cement slurry column pressure transmission rate calculated according to the indoor test; is the flow rate of the fluid flowing through the on-site cement slurry column; is the viscosity of the fluid flowing through the on-site cement slurry column; is the length of the cement slurry column at the calculation end; is the outer diameter of the on-site cementing cement ring; is the inner diameter of the on-site cementing cement ring; is the upper pressure of the cement slurry column for on-site calculation section; is the cross-sectional area of the cement slurry column for indoor test experiment; is the pressure difference between the upper and lower ends of the cement slurry column for indoor test experiment; is the pressure difference between the upper and lower ends of the cement slurry column for indoor test experiment; is the fluid viscosity of the fluid flowing through the cement slurry column for indoor test experiment; is the length of the cement slurry column for indoor test experiment; Take π as 3.14.

[0038] As Figure 1 shown, a device for testing the pressure transmission rate during the whole hydration process of oil and gas well cement slurry of the present invention includes a sealed test slurry cup, a cement slurry heating system, a pressure medium temperature and pressure control system, a cement slurry temperature control system, and a cement slurry lower end pressure monitoring system.

[0039] The sealed test slurry cup for containing the cement slurry to be tested is divided into a test inner cylinder 3 and a test outer cylinder 2. The test inner cylinder 3 contains the cement slurry 4 to be tested, and a heat-conducting medium is contained in the annular space between the test outer cylinder 2 and the test inner cylinder 3. The inner diameter of the test inner cylinder 3 is 5 cm, the thickness is 0.5 cm, and the height is 100 cm; the inner diameter of the test outer cylinder 2 is 15 cm, the thickness is 1 cm, and the height is 100 cm.

[0040] The test top cover 6 is located at the top of the test outer cylinder 2, and the test base 1 is located at the bottom of the test outer cylinder 2. The test top cover 6 and the test base 1 are respectively fixed on both sides of the test outer cylinder 2 through screws, and the test top cover 6 and the test base 1 are respectively sealed with the test outer cylinder 2 and the test inner cylinder 3 through sealing rubber rings.

[0041] The diameter of the cement slurry 4 to be tested is 5 cm and the height is 50 - 90 cm, the diameter of the cement slurry 13 to be heated is 10 cm and the height is < 30 cm, and the diameter of the pressure medium 27 is 10 cm and the height is 30 cm.

[0042] The sealed test slurry cup for containing the cement slurry to be tested is equipped with a cement slurry heating system for heating the cement slurry, a pressure medium temperature and pressure control system for heating and controlling the temperature and pressure of the heating medium at the upper end of the cement slurry, a cement slurry temperature control system for controlling the temperature of the cement slurry during the test process, and a cement slurry lower end pressure monitoring system for monitoring the change of the pressure at the lower end of the cement slurry.

[0043] The cement slurry heating system is sequentially connected to the sealed test slurry cup through the second interface 9, the first valve 8, and the first interface 7.

[0044] The pressurized medium temperature and pressure control system is successively connected to the sealed test slurry cup through the third interface 29, the second valve 30, and the upper hydraulic interface 31.

[0045] The sensors of the cement slurry temperature control system and the sensors of the cement slurry lower-end pressure monitoring system are both connected to the computer control and acquisition system 60.

[0046] The cement slurry heating system includes a sealed heating slurry cup for containing the cement slurry to be heated, a cement slurry heating device for heating the cement slurry, and a transmission device for stirring the cement slurry during the heating process. The sealed heating slurry cup includes a heating base 10, a heating kettle body 11, a heating top cover 16, a sealed bearing 17, a sealed cover 19, and a magnetic drive paddle 20. The heating base 10 and the heating top cover 16 are respectively connected to the heating kettle body 11 by threads. The heating base 10 is located at the bottom of the heating kettle body 11, and the heating top cover 16 is located at the top of the heating kettle body 11. Between the heating base 10 and the heating kettle body 11, and between the heating top cover 16 and the heating kettle body 11 are sealed by sealing rubber rings. The sealed cover 19 is connected to the heating top cover 16 by threads, and between the sealed cover 19 and the heating top cover 16 is sealed by a sealing ring. The inner diameter of the sealed heating slurry cup is 10 cm, the thickness is 1 cm, and the height is 30 cm. A sealed bearing 17 is installed in the middle of the heating top cover 16, and the magnetic drive paddle 20 is installed on the sealed bearing 17.

[0047] The sealed heating slurry cup is connected to a nitrogen cylinder 56 through a heating air pressure interface 21, a first pressure dividing valve 41, and a four-way valve 42, and can control the pressure borne by the cement slurry during the heating process. The heating air pressure interface 21 is installed on the heating top cover 16.

[0048] The transmission device includes a motor 14, an electric pulley 15, and a magnetic drive pulley 18. The magnetic drive pulley 18 is installed outside the sealed cover 19. The magnetic drive pulley 18 is connected to the electric pulley 15 by a belt. The magnetic drive pulley 18 can drive the magnetic drive paddle 20 to rotate through magnetic force. The electric pulley 15 is connected to the motor 14 through a transmission shaft. The motor 14 is connected to the computer control and acquisition system 60 and is directly controlled by it.

[0049] The cement slurry heating device includes a second heating sleeve 12, a temperature sensor d23 for measuring the temperature of the second heating sleeve 12, and a temperature sensor c22 for measuring the temperature of the cup body of the sealed heating slurry cup. The signal output ends of the temperature sensor c22, the temperature sensor d23, and the second heating sleeve 12 are respectively connected to a temperature control device 55. The signal output end of the temperature control device 55 is connected to the computer control and acquisition system 60. The second heating sleeve 12 is sleeved on the cup body of the sealed heating slurry cup. The temperature sensor d23 is installed on the second heating sleeve 12, and the temperature sensor c22 is installed on the heating kettle body 11.

[0050] The pressurized medium temperature and pressure control system includes a sealed pressurized slurry cup for containing the pressurized medium, a medium heating device for heating the pressurized medium, and a pressurized medium pressure control device for controlling the pressure of the pressurized medium.

[0051] The sealed pressurized slurry cup includes a pressurized top cover 24, a pressurized kettle body 26, and a pressurized base 28. The pressurized top cover 24 and the pressurized base 28 are respectively connected to the pressurized kettle body 29 by threads. The pressurized top cover 24 is located at the top of the pressurized kettle body 26, and the pressurized base 28 is located at the bottom of the pressurized kettle body 26. Between the pressurized top cover and the pressurized kettle body 26, and between the pressurized base 28 and the pressurized kettle body 26, they are sealed by sealing rubber rings. The inner diameter of the sealed pressurized slurry cup is 10 cm, the thickness is 0.5 cm, and the height is 30 cm.

[0052] The pressurized medium heating device includes a third heating jacket 25, a temperature sensor f40 for measuring the temperature of the third heating jacket 25, and a temperature sensor e39 for measuring the temperature of the cup body of the sealed pressurized slurry cup. The signal output ends of the temperature sensor e39, the temperature sensor f40, and the third heating jacket 26 are respectively connected to a temperature control device 55, and the signal output end of the temperature control device 55 is connected to a computer control and acquisition system 60. A fourth interface 38 is installed on the pressurized top cover 24. The temperature sensor f40 is installed on the third heating jacket 25, and the temperature sensor e39 is installed on the sealed pressurized slurry cup.

[0053] The pressurized medium pressure control device for controlling the pressure of the pressurized medium includes a fourth interface 38, a pressurized medium supply container 54, an upper pressurizing device 58, an upper pressure sensor 61, and a fifth valve 57. The fourth interface 38 is connected to the upper pressurizing device 58 through a hydraulic pipeline, and a fifth valve 57 is installed on this hydraulic pipeline. An upper pressure sensor 61 is installed at the outlet of the upper pressurizing device 58. The upper pressurizing device 58 can control and stabilize the medium pressure. The upper pressurizing device 58 is connected to the pressurized medium supply container 54 through a hydraulic pipeline and a sixth valve 59. The pressurized medium supply container 54 contains sizing water.

[0054] The cement slurry temperature control system includes a first heating jacket 5 for controlling the temperature of the cement slurry during the test, a temperature sensor b35 for measuring the temperature of the first heating jacket 5, a temperature sensor a33 for measuring the temperature of the cement slurry, a heat transfer medium supply container 49, and a temperature control device 55. The first heating jacket 5 is sleeved on the test outer cylinder 3. The signal output ends of the temperature sensor a33, the temperature sensor b35, and the first heating jacket 5 are respectively connected to the temperature control device 55, and the signal output end of the temperature control device 55 is connected to the computer control and acquisition system 60. The upper end air pressure interface 32 and the annulus upper end interface 34 are both installed on the test top cover 6, and the annulus lower end interface 36 and the lower end pressure measurement interface 37 are both installed on the test base 1. The temperature sensor a33 is installed in the cement slurry to be tested 4, and the temperature sensor b35 is installed on the first heating jacket 5. The test top cover 6 is connected to the nitrogen cylinder 56 through the upper end air pressure interface 32, and through an air pressure pipeline, a pressure reducing valve II 46, and a four-way valve 42.

[0055] The heat transfer medium supply container 49 is filled with a heat transfer medium for controlling the temperature of the cement slurry during the test. The initial boiling point of the heat transfer medium is 320 °C, the flash point is 255 °C, and the pour point is -15 °C.

[0056] The bottom end of the heat transfer medium supply container 49 is connected to the annulus lower end interface 36 through a hydraulic pipeline, and a third valve 50 is installed on this hydraulic pipeline; the upper end of the heat transfer medium supply container 49 is connected to the annulus upper end interface 34 through an air pressure pipeline, a three-way valve II 45, a three-way valve I 43, and a three-way valve III 47; the upper end of the heat transfer medium supply container 49 is connected to the nitrogen cylinder 56 through an air pressure pipeline, a three-way valve II 45, a three-way valve I 43, and a four-way valve 42, and is connected to the vent valve I 44 through an air pressure pipeline and a three-way valve II 45. A vent valve II 48 is installed at the end of the pipeline where the three-way valve III 47 is located.

[0057] The cement slurry lower end pressure monitoring system includes a lower end pressure measurement interface 37, a fourth valve 51, a lower end pressure sensor 52, and a lower end micro-leakage container 53; The inside of the lower end pressure measurement interface 37 contains a filter element to prevent the cement slurry from entering the lower end hydraulic pipeline. The lower end pressure measurement interface 37 is connected to the lower end micro-leakage container 53 through a hydraulic pipeline, and a fourth valve 51 is also installed on the hydraulic pipeline. The lower end micro-leakage container 53 is processed to leak at a micro-flow rate of a (the value range of a is 0.001 - 0.01) cm 3 / s within a certain pressure range, and the lower end micro-leakage container 53 is filled with prepared slurry water. The signal acquisition end of the lower end pressure sensor 52 is connected to the lower end micro-leakage container 53, and the signal output end is connected to the computer control and acquisition system 60.

[0058] During the test of the cement slurry, both the upper and lower end faces are in contact with the prepared slurry water, which has no impact on the hydration and structure formation of the cement slurry.

[0059] The computer control system 60 can record in real time the change process and current values of curves such as the temperature and pressure of the cement slurry and the pressurizing medium.

[0060] Another aspect of the present invention also provides a testing method based on the above-mentioned testing device for the pressure transmission rate during the whole hydration process of oil and gas well cement slurry, which successively includes the following steps: (1). Seal the test base 1 and the test top cover 6 with sealing rubber rings to the test inner cylinder 3 respectively, and install them on the test outer cylinder 2 through screws; (2). After sealing the pressurizing base 28 and the pressurizing kettle body 26 with a sealing rubber ring and connecting them by threads, connect the upper hydraulic interface 31 to the test top cover 6 by threads. The upper hydraulic interface 31 is connected to the third interface 29 through a hydraulic pipeline and a second valve 30. Connect the third interface 29 to the pressurizing base 28 by threads. Close the second valve 30, fill the pressurizing kettle body 26 with mixing water, connect the pressurizing top cover 24 to the pressurizing kettle body 26 by threads, and seal it with a sealing ring.

[0061] (3). Seal the heating base 10 and the heating kettle body 11 with a sealing rubber ring and connect them by threads. Connect the first interface 7 to the test top cover 6 by threads. The first interface 7 is connected to the second interface 9 through a hydraulic pipeline and a first valve 8. Connect the second interface 9 to the heating base 10 by threads. Close the first valve 8, install the magnetic drive impeller 20 in the heating kettle body 11, pour the prepared cement slurry into the heating kettle body 11, connect the heating top cover 16 to the heating kettle body 11 by threads, and seal it with a sealing ring. Install the sealing bearing 17 on the heating top cover 16 by a buckle. The sealing bearing 17 is sealed with the heating top cover 16 and the magnetic drive impeller 20 through a sealing ring. Connect the sealing cover 19 to the heating top cover 16 by threads and seal it with a sealing ring. Install the magnetic drive pulley 18 outside the sealing cover 19 and connect it to the electric pulley 15 through a belt.

[0062] (4). Insert the temperature sensor a33 into the inner cylinder 3 to be tested and tightly connect it to the test top cover 6 through threads and a sealing ring. The temperature sensor a33 is in direct contact with the cement slurry 4 to be tested during the test. For easy disassembly, a layer of high-temperature resistant lubricating oil can be applied to its surface. Connect the temperature sensor b35 to the first heating sleeve 5, insert the temperature sensor c22 into the heating kettle body 11 and tightly connect it to the heating kettle body 11 through threads, connect the temperature sensor d23 to the second heating sleeve 12, insert the temperature sensor e39 into the pressurizing medium and tightly connect it to the pressurizing top cover 24 through threads and a sealing ring, connect the temperature sensor f40 to the third heating sleeve 25, and connect the temperature control device 55 to the first heating sleeve 5, the second heating sleeve 12, the third heating sleeve 25, the temperature sensor a33, the temperature sensor b35, the temperature sensor c22, the temperature sensor d23, the temperature sensor e39, the temperature sensor f40, and the computer control and acquisition system 60 respectively through data lines.

[0063] (5). Fill the heat-conducting medium supply container 49 with the heat-conducting medium. Connect the heat-conducting medium supply container 49 to the four-way valve 42 through a pneumatic pipeline via the three-way valve II 45 and the three-way valve I 43. Connect the heat-conducting medium supply container 49 to the atmosphere through a pneumatic pipeline via the three-way valve II 45 and the vent valve I d44. Connect the upper pneumatic interface 32 to the four-way valve 42 through a hydraulic pipeline via the pressure reducing valve II 46. The upper pneumatic interface 32 is connected to the test top cover 6 through threads. Connect the upper annulus interface 34 to the four-way valve 42 through a pneumatic pipeline via the three-way valve III 47 and the three-way valve I 43. The upper annulus interface 34 is connected to the atmosphere via the three-way valve III 47 and the vent valve II 48. The upper annulus interface 34 is connected to the test top cover 6 through threads. Connect the heating pneumatic interface 21 to the four-way valve 42 through a pneumatic pipeline via the first pressure reducing valve 41. The heating pneumatic interface 21 is connected to the heating top cover 16 through threads. Connect the lower annulus interface 36 to the heat-conducting medium supply container 49 through a pipeline via the third valve 50. The lower annulus interface 36 is connected to the test base 1 through threads. Connect the four-way valve 42 to the nitrogen cylinder 56 through a pneumatic pipeline.

[0064] (6). Connect one end of the lower pressure sensor 52 to the lower micro-leakage container 53 and the other end to the computer control and acquisition system 60. Connect one end of the lower micro-leakage container 53 to the lower pressure measurement interface 37 through a hydraulic pipeline via the fourth valve 51, and the other end to the atmosphere through a leakage pipeline. Connect the lower pressure measurement interface 37 to the test base 1 through threads.

[0065] (7). Connect one end of the upper pressure sensor 61 to the upper pressurizing device 58 and the other end to the computer-controlled acquisition system 60. Connect one end of the upper pressurizing device 58 to the fourth interface 38 through the fifth valve 57 via a hydraulic pipeline, and connect the other end to the pressurizing medium supply container 54 through the sixth valve 59 via a hydraulic pipeline. Connect the fourth interface 38 to the pressurizing top cover 24 by means of a threaded connection.

[0066] (8). Before the experiment, ensure that all valves are closed. Open the nitrogen cylinder 56, four-way valve 42, three-way valve I 43, three-way valve II 45, third valve 50, three-way valve III 47, and vent valve II 48. Fill the annular space formed between the test outer cylinder 2 and the test inner cylinder 3 with the heat-conducting medium from the heat-conducting medium supply container 49. Close the three-way valve III 47 and the vent valve II 48, and open the vent valve I 44.

[0067] (9). Open the fifth valve 57 and the sixth valve 59, start the upper pressurizing device 58, set the target pressure, and use the upper pressurizing device 58 to continuously and evenly pressurize the upper end of the pressurizing medium 27 through the fourth interface 38 until the target pressure is reached and the target pressure is maintained. (10). Open the pressure-dividing valve I 41 and use the pressure-dividing valve I 41 to control the upper-end pressure of the cement slurry 13 to be heated during the heating process through the heating air-pressure interface 21. Open the pressure-dividing valve II 46 and use the pressure-dividing valve II 46 to control the pressure inside the test inner cylinder 3 through the upper-end air-pressure interface 32. (11). Start the motor 14 through the computer-controlled acquisition system 60 and use the electric pulley 15 and the magnetic drive pulley 18 to control the magnetic drive impeller 20 to stir the cement slurry at a rotational speed of b (the value range of b is 1505) r / min. (12). Open the temperature control device 55, preset the heating temperature and the heating rate, and respectively control the first heating jacket 5, the second heating jacket 12, and the third heating jacket 25 to heat the test inner cylinder 3, the cement slurry 13 to be heated, and the pressurizing medium 27. Open the computer-controlled acquisition system 60 to record the temperatures inside the test inner cylinder 3, the cement slurry 13 to be heated, and the heating medium 27.

[0068] (13). After the temperature of the cement slurry 13 to be heated rises to the preset heating temperature, open the first valve 8. Due to the pressure difference, the cement slurry 13 to be heated is pressed from the heating kettle body 11 into the test inner cylinder 3. Open the second valve 30 and use the upper pressurizing device 58 to control the upper-end pressure of the cement slurry 4 to be measured to be P1 (2 - 9 MPa) by means of the pressurizing medium 27. Open the fourth valve 51, start the lower pressure sensor 52, and use the lower micro-leakage control container 53 to control the mixing water to flow out at a constant micro-flow rate of a (the value range of a is 0.001 - 0.01) cm 3 / s.

[0069] (14). Record the pressure changes at the upper and lower ends of the cement slurry 4 to be measured through the computer-controlled acquisition system 60.

[0070] (15). After the experiment, the computer-controlled acquisition system 60 saves the experimental data, turns off the temperature control device 55. After the experimental device cools down to room temperature, use the upper pressure application device 58 to relieve the pressure at the upper end of the cement slurry 4 to be measured, close the upper pressure application device 58, the fifth valve 57, and the fourth valve 51. Open the three-way valve III 47, press the heat transfer medium into the heat transfer medium supply container 49, close the nitrogen cylinder 56. After the air pressure in the device is completely released, close all valves, remove the pipelines of each device and the monitoring system, remove the test base 1 and the test top cover 6, take out the test sample, and clean the first interface 7, the first valve 8, the second interface 9, the heating base 10, the heating kettle body 11, and the heating top cover 16.

[0071] Example 1 Test cement slurry formula: Jiahua G-grade cement + 44% water Test conditions: 60 °C, pressure 7 MPa (1). Seal the test base 1 and the test top cover 6 with sealing rubber rings to the test inner cylinder 3 respectively, and install them on the test outer cylinder 2 through screws. (2). Seal the pressure application base 28 and the pressure application kettle body 26 with a sealing rubber ring and connect them by thread. Connect the upper hydraulic interface 31 to the test top cover 6 by thread. The upper hydraulic interface 31 is connected to the third interface 29 through a hydraulic pipeline and the second valve 30. Connect the third interface 29 to the pressure application base 28 by thread. Close the second valve 30, fill the pressure application kettle body 26 with mixing water, connect the pressure application top cover 24 to the pressure application kettle body 26 by thread, and seal it with a sealing ring.

[0072] (3). Seal the heating base 10 and the heating kettle body 11 with a sealing rubber ring and connect them by thread. Connect the first interface 7 to the test top cover 6 by thread. The first interface 7 is connected to the second interface 9 through a hydraulic pipeline and the first valve 8. Connect the second interface 9 to the heating base 10 by thread. Close the first valve 8, install the magnetic drive impeller 20 in the heating kettle body 11, pour the prepared cement slurry into the heating kettle body 11, connect the heating top cover 16 to the heating kettle body 11 by thread, and seal it with a sealing ring. Install the sealing bearing 17 on the heating top cover 16 by snap, and seal the sealing bearing 17 with the heating top cover 16 and the magnetic drive impeller 20 with a sealing ring. Connect the sealing cover 19 to the heating top cover 16 by thread and seal it with a sealing ring. Install the magnetic drive pulley 18 outside the sealing cover 19 and connect it to the electric pulley 15 through a belt.

[0073] (4). Insert the temperature sensor a33 into the inner cylinder 3 to be tested and tightly connect it to the test top cover 6 through threads and a sealing ring. The temperature sensor a33 is in direct contact with the cement slurry 4 to be tested during the test. For easy disassembly, a layer of high-temperature resistant lubricating oil can be applied to its surface; connect the temperature sensor b35 to the first heating sleeve 5, insert the temperature sensor c22 into the heating kettle body 11 and tightly connect it to the heating kettle body 11 through threads, connect the temperature sensor d23 to the second heating sleeve 12, insert the temperature sensor e39 into the pressurizing medium and tightly connect it to the pressurizing top cover 24 through threads and a sealing ring, connect the temperature sensor f40 to the third heating sleeve 25, and connect the temperature control device 55 to the first heating sleeve 5, the second heating sleeve 12, the third heating sleeve 25, the temperature sensor a33, the temperature sensor b35, the temperature sensor c22, the temperature sensor d23, the temperature sensor e39, the temperature sensor f40, and the computer control and acquisition system 60 respectively through data lines.

[0074] (5). Fill the heat-conducting medium supply container 49 with the heat-conducting medium. Connect the heat-conducting medium supply container 49 to the four-way valve 42 through the three-way valve II 45 and the three-way valve I 43 via a pneumatic pipeline. Connect the heat-conducting medium supply container 49 to the atmosphere through the three-way valve II 45 and the vent valve I d44 via a pneumatic pipeline. Connect the upper pneumatic interface 32 to the four-way valve 42 through the pressure reducing valve II 46 via a pneumatic pipeline. The upper pneumatic interface 32 is connected to the test top cover 6 through threads. Connect the upper annulus interface 34 to the four-way valve 42 through the three-way valve III 47 and the three-way valve I 43 via a pneumatic pipeline. The upper annulus interface 34 is connected to the atmosphere through the three-way valve III 47 and the vent valve II 48. The upper annulus interface 34 is connected to the test top cover 6 through threads. Connect the heating pneumatic interface 21 to the four-way valve 42 through the first pressure reducing valve 41 via a hydraulic pipeline. The heating pneumatic interface 21 is connected to the heating top cover 16 through threads. Connect the lower annulus interface 36 to the heat-conducting medium supply container 49 through the third valve 50 via a pipeline. The lower annulus interface 36 is connected to the test base 1 through threads. Connect the four-way valve 42 to the nitrogen cylinder 56 via a pneumatic pipeline.

[0075] (6). Connect one end of the lower pressure sensor 52 to the lower micro-leakage container 53 and the other end to the computer control and acquisition system 60. Connect one end of the lower micro-leakage container 53 to the lower pressure measurement interface 37 through the fourth valve 51 via a hydraulic pipeline and the other end to the atmosphere through a leakage pipeline. Connect the lower pressure measurement interface 37 to the test base 1 through threads.

[0076] (7). Connect one end of the upper pressure sensor 61 to the upper pressurizing device 58, and the other end to the computer-controlled acquisition system 60. Connect one end of the upper pressurizing device 58 to the fourth interface 38 through the fifth valve 57 via a hydraulic pipeline, and the other end to the pressurizing medium supply container 54 through the sixth valve 59 via a hydraulic pipeline. Connect the fourth interface 38 to the pressurizing top cover 24 by threaded connection.

[0077] (8). Before the experiment, ensure that all valves are closed. Open the nitrogen cylinder 56, four-way valve 42, three-way valve I 43, three-way valve II 45, third valve 50, three-way valve III 47, and vent valve II 48. Fill the annular space formed between the test outer cylinder 2 and the test inner cylinder 3 with the heat-conducting medium from the heat-conducting medium supply container 49. Close the three-way valve 47 and the vent valve II 48, and open the vent valve I 44.

[0078] (9). Open the fifth valve 57 and the sixth valve 59, start the upper pressurizing device 58, set the target pressure to 7 MPa, and use the upper pressurizing device 58 to continuously and evenly pressurize the upper end of the pressurizing medium 27 through the fourth interface 38 until the target pressure is reached and the target pressure is maintained. (10). Open the pressure dividing valve I 41, and use the pressure dividing valve I 41 to control the upper end pressure of the cement slurry to be heated 13 during heating to 6 MPa through the heating air pressure interface 21. Open the pressure dividing valve II 46, and use the pressure dividing valve II 46 to control the pressure inside the test inner cylinder 3 to 5 MPa through the upper air pressure interface 32. (11). Start the motor 14 through the computer-controlled acquisition system 60 and use the electric pulley 15 and the magnetic drive pulley 18 to control the magnetic drive blade 20 to stir the cement slurry at a rotational speed of b (the value range of b is 150 - 5) r / min. (12). Open the temperature control device 55, preset the heating temperature to 60 °C and the heating rate to 2 °C / min, and respectively control the first heating jacket 5, the second heating jacket 12, and the third heating jacket 25 to heat the cement slurry to be tested 4, the cement slurry to be heated 12, and the pressurizing medium 27. Open the computer-controlled acquisition system 60 to record the temperatures inside the test inner cylinder 3, the cement slurry to be heated 13, and the heating medium 27.

[0079] (13). After the temperature of the cement slurry to be heated 13 rises to the preset heating temperature, open the first valve 8. Through the pressure difference, the cement slurry to be heated 13 is pressed from the heating kettle body 11 into the test inner cylinder 3. Open the second valve 30, and use the upper pressurizing device 58 to control the upper end pressure of the cement slurry to be tested 4 to 7 MPa by using the pressurizing medium 27. Open the fourth valve 51, start the lower pressure sensor 52, and use the lower micro-leakage control container 53 to control the mixing water to flow out at a constant micro-flow rate of a (the value range of a is 0.001 - 0.01) cm 3 / s.

[0080] (14). Record the pressure changes at the upper and lower ends of the cement slurry 4 to be measured through the computer-controlled acquisition system 60.

[0081] (15). After the experiment, the computer-controlled acquisition system 60 saves the experimental data, turns off the temperature control device 55. After the experimental device cools down to room temperature, use the upper end pressurizing device 58 to relieve the pressure at the upper end of the cement slurry 4 to be measured, close the upper end pressurizing device 58, the fifth valve 57, and the fourth valve 51. Open the three-way valve III 47, press the heat transfer medium into the heat transfer medium supply container 49, close the nitrogen cylinder 56. After the air pressure in the device is completely released, close all valves, remove the pipelines of each device and the monitoring system, remove the test base 1 and the test top cover 6, take out the test sample, and clean the first interface 7, the first valve 8, the second interface 9, the heating base 10, the heating kettle body 11, and the heating top cover 16.

[0082] The test data is shown in Figure 2 , calculate the pressure transmission rate of the on-site cement slurry column. Within 3.5 hours of cement slurry hydration, the cement slurry column can completely transmit the pressure applied at the upper end; during the period of 3.5 - 20.7 hours of cement slurry hydration, the pressure transmission of the cement slurry column drops from 100% to 0; when the cement slurry hydration exceeds 20.7 hours, the pressure applied at the upper end of the slurry column can no longer be transmitted to the bottom end at all.

[0083] Example 2 Test cement slurry formula: Jiahua G-grade cement + 44% water Test conditions: temperature 120°C, pressure 7 MPa (1). Seal the test base 1 and the test top cover 6 with sealing rubber rings to the test inner cylinder 3 respectively, and install them on the test outer cylinder 2 through screws. (2). After sealing the pressurizing base 28 and the pressurizing kettle body 26 with a sealing rubber ring, connect them by thread. Connect the upper end hydraulic interface 31 to the test top cover 6 by thread. The upper end hydraulic interface 31 is connected to the third interface 29 through a hydraulic pipeline and the second valve 30. Connect the third interface 29 to the pressurizing base 28 by thread. Close the second valve 30, fill the pressurizing kettle body 26 with mixing water, connect the pressurizing top cover 24 to the pressurizing kettle body 26 by thread, and seal it with a sealing ring.

[0084] (3). Seal the heating base 10 and the heating kettle body 11 with a sealing rubber ring and connect them by threads. Connect the first interface 7 to the test top cover 6 by threads. The first interface 7 is connected to the second interface 9 through a hydraulic pipeline and a first valve 8. Connect the second interface 9 to the heating base 10 by threads. Close the first valve 8. Install the magnetic drive impeller 20 in the heating kettle body 11. Pour the prepared cement slurry into the heating kettle body 11. Connect the heating top cover 16 to the heating kettle body 11 by threads and seal it with a sealing ring. Install the sealed bearing 17 on the heating top cover 16 by a buckle. The sealed bearing 17 is sealed with the heating top cover 16 and the magnetic drive impeller 19 through a sealing ring. Connect the sealing cover 19 to the heating top cover 16 by threads and seal it with a sealing ring. Install the magnetic drive pulley 18 outside the sealing cover 19 and connect it to the electric pulley 15 by a belt.

[0085] (4). Insert the temperature sensor a33 into the inner cylinder 3 to be tested and tightly connect it to the test top cover 6 through threads and a sealing ring. The temperature sensor a33 is in direct contact with the cement slurry 4 to be tested during the test. For easy disassembly, a layer of high-temperature resistant lubricating oil can be applied to its surface. Connect the temperature sensor b35 to the first heating sleeve 5. Insert the temperature sensor c22 into the heating kettle body 11 and tightly connect it to the heating kettle body 11 through threads. Connect the temperature sensor d23 to the second heating sleeve 12. Insert the temperature sensor e39 into the pressurizing medium and tightly connect it to the pressurizing top cover 24 through threads and a sealing ring. Connect the temperature sensor f40 to the third heating sleeve 25. Connect the temperature control device 55 to the first heating sleeve 5, the second heating sleeve 12, the third heating sleeve 25, the temperature sensor a33, the temperature sensor b35, the temperature sensor c22, the temperature sensor d23, the temperature sensor e39, the temperature sensor f40 and the computer control acquisition system 60 respectively through data lines.

[0086] (5). Fill the heat-conducting medium supply container 49 with the heat-conducting medium. Connect the heat-conducting medium supply container 49 to the four-way valve 42 through the pneumatic pipeline via the three-way valve II 45 and the three-way valve I 43. Connect the heat-conducting medium supply container 49 to the atmosphere through the pneumatic pipeline via the three-way valve II 45 and the vent valve I d44. Connect the upper pneumatic interface 32 to the four-way valve 42 through the hydraulic pipeline via the pressure dividing valve II 46. Connect the upper pneumatic interface 31 to the test top cover 6 by thread. Connect the annulus upper interface 33 to the four-way valve 42 through the pneumatic pipeline via the three-way valve III 47 and the three-way valve I 43. Connect the annulus upper interface 34 to the atmosphere via the three-way valve III 47 and the vent valve II 48. Connect the annulus upper interface 34 to the test top cover 6 by thread. Connect the heating pneumatic interface 21 to the four-way valve 42 through the pneumatic pipeline via the first pressure dividing valve 41. Connect the heating pneumatic interface 21 to the heating top cover 16 by thread. Connect the annulus lower interface 36 to the heat-conducting medium supply container 49 through the pipeline via the third valve 50. Connect the annulus lower interface 36 to the test base 1 by thread. Connect the four-way valve 42 to the nitrogen cylinder 56 through the pneumatic pipeline.

[0087] (6). Connect one end of the lower pressure sensor 52 to the lower micro-leakage container 53 and the other end to the computer-controlled acquisition system 60. Connect one end of the lower micro-leakage container 53 to the lower pressure measurement interface 37 through the hydraulic pipeline via the fourth valve 51 and the other end to the atmosphere through the leakage pipeline. Connect the lower pressure measurement interface 37 to the test base 1 by thread.

[0088] (7). Connect one end of the upper pressure sensor 61 to the upper pressurizing device 58 and the other end to the computer-controlled acquisition system 60. Connect one end of the upper pressurizing device 58 to the fourth interface 38 through the hydraulic pipeline via the fifth valve 57 and the other end to the pressurizing medium supply container 54 through the hydraulic pipeline via the sixth valve 59. Connect the fourth interface 38 to the pressurizing top cover 24 by thread.

[0089] (8). Before the experiment, ensure that all valves are closed. Open the nitrogen cylinder 56, the four-way valve 42, the three-way valve I 43, the three-way valve II 45, the third valve 50, the three-way valve III 47, and the vent valve II 48. Fill the annular space formed between the test outer cylinder 2 and the test inner cylinder 3 with the heat-conducting medium from the heat-conducting medium supply container 49. Close the three-way valve 47 and the vent valve II 48, and open the vent valve I 44.

[0090] (9). Open the fifth valve 57 and the sixth valve 59. Start the upper pressurizing device 58, set the target pressure to 7 MPa, and use the upper pressurizing device 58 to continuously and evenly pressurize the upper end of the pressurizing medium 27 through the fourth interface 38 until the target pressure is reached and the target pressure is maintained. (10). Open the pressure reducing valve I 41, and use the pressure reducing valve I 41 to control the upper pressure of the cement slurry to be heated 13 during heating to 6 MPa through the heating air pressure interface 21. Open the pressure reducing valve II 46, and use the pressure reducing valve II 46 to control the pressure in the test inner cylinder 3 to 5 MPa through the upper air pressure interface 32; (11). Start the motor 14 through the computer control acquisition system 60, and use the electric pulley 15 and the magnetic drive pulley 18 to control the magnetic drive blade 20 to stir the cement slurry at a rotational speed of 1505 r / min; (12). Open the temperature control device 55, preset the heating temperature to 120 °C and the heating rate to 2 °C / min, and respectively control the first heating jacket 5, the second heating jacket 12, and the third heating jacket 25 to heat the test inner cylinder, the cement slurry to be heated 13, and the pressurizing medium 27. Open the computer control acquisition system 60 to record the temperatures in the test inner cylinder 3, the cement slurry to be heated 13, and the heating medium 27.

[0091] (13). After the temperature of the cement slurry to be heated 13 rises to the preset heating temperature, open the first valve 8. Through the pressure difference, the cement slurry to be heated 13 is pressed from the heating kettle body 11 into the test inner cylinder 3. Open the second valve 30, and use the pressurizing medium 27 through the upper pressurizing device 58 to control the upper pressure of the cement slurry to be tested 4 to 7 MPa. Open the fourth valve 51, start the lower pressure sensor 52, and use the lower micro-leakage control container 53 to control the mixing water to flow out at a constant micro-flow rate a (the value range of a is 0.001~0.01) cm 3 / s.

[0092] (14). Record the changes in the upper and lower pressures of the cement slurry to be tested 4 through the computer control acquisition system 60.

[0093] (15). After the experiment is over, the computer control acquisition system 60 saves the experimental data, closes the temperature control device 55. After the experimental device cools down to room temperature, use the upper pressurizing device 58 to relieve the upper pressure of the cement slurry to be tested 4, close the upper pressurizing device 58, the fifth valve 57, and the fourth valve 51. Open the three-way valve III 47, press the heat transfer medium into the heat transfer medium supply container 49, close the nitrogen cylinder 56. After the air pressure of the device is completely released, close all valves, remove the pipelines of each device and the monitoring system, remove the test base 1 and the test top cover 6, take out the test sample, and clean the first interface 7, the first valve 8, the second interface 9, the heating base 10, the heating kettle body 11, and the heating top cover 16.

[0094] The test data is shown in Figure 3, calculate the pressure transfer rate of the on-site cement slurry column. Within 4.5 hours of cement slurry hydration, the cement slurry column can completely transfer the pressure applied at the upper end; during the period of 3.5 - 6.9 hours of cement slurry hydration, the pressure transfer of the cement slurry column drops from 100% to 0; when the cement slurry hydration exceeds 6.9 hours, the pressure applied at the upper end of the slurry column can no longer be transferred to the bottom end at all.

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A testing device for the pressure transmission rate during the whole hydration process of oil and gas well cement slurry, characterized in that, It includes a sealed test slurry cup, a cement slurry heating system, a pressure medium temperature and pressure control system, a cement slurry temperature control system, and a cement slurry lower-end pressure monitoring system. The cement slurry heating system is sequentially connected to the sealed test slurry cup through a second interface, a first valve, and a first interface. The pressure medium temperature and pressure control system is sequentially connected to the sealed test slurry cup through a third interface, a second valve, and an upper-end hydraulic interface. The cement slurry temperature control system and the cement slurry lower-end pressure monitoring system collect data of the test device, and the sensors of the cement slurry temperature control system and the cement slurry lower-end pressure monitoring system are both connected to the computer control acquisition system.

2. The device according to claim 1, wherein The sealed test slurry cup is divided into a test inner cylinder and a test outer cylinder. The test inner cylinder contains the cement slurry to be tested, and a heat-conducting medium is contained in the annular space between the test outer cylinder and the test inner cylinder. The test top cover and the test bottom base are respectively fixed on both sides of the test outer cylinder through screws. The test top cover and the test bottom base are respectively sealed with the test outer cylinder and the test inner cylinder through sealing rubber rings. The annulus between the test inner cylinder and the test outer cylinder is connected to a nitrogen cylinder through an upper annulus interface, a three-way valve III, a three-way valve I, and a four-way valve. The annulus is connected to a vent valve II through an upper annulus interface and a three-way valve III. The upper end of the annulus is connected to the upper end of the heat-conducting medium supply container through an upper annulus interface, a three-way valve III, a three-way valve I, and a three-way valve II. The bottom end of the annulus between the test inner cylinder and the test outer cylinder is connected to the lower end of the heat-conducting medium supply container through a lower annulus interface and a third valve. The heat-conducting medium supply container is connected to a vent valve I through a three-way valve II.

3. The device according to claim 2, wherein, A first heating jacket is sleeved on the test outer cylinder.

4. The device according to claim 1, characterized in that , the cement slurry heating system includes a sealed heating slurry cup, a heating device, and a transmission device; The sealed heating slurry cup includes a heating base, a heating kettle body, a heating top cover, a sealed bearing, a sealed cover, and a magnetic drive impeller. The heating base and the heating top cover are respectively connected to the heating kettle body through threads. The heating base and the heating top cover are both sealed with the heating kettle body through sealing rings. The sealed cover is connected to the heating top cover through a thread. A sealed bearing is installed in the middle of the heating top cover, and the magnetic drive impeller is installed on the sealed bearing. The upper end of the sealed heating slurry cup is connected to a nitrogen cylinder through a heating air pressure interface, a first pressure reducing valve, and a four-way valve; The heating device includes a second heating jacket sleeved outside the heating kettle body, a temperature sensor d installed on the heating kettle body, and a temperature sensor c installed on the second heating jacket. The signal output ends of the temperature sensor c, the temperature sensor d, and the second heating jacket are respectively connected to a temperature control device. The signal output end of the temperature control device is connected to the computer control acquisition system; The transmission device includes a motor, an electric pulley, and a magnetic drive pulley. The magnetic drive pulley is installed outside the sealed cover. The magnetic drive pulley is connected to the electric pulley through a belt. The magnetic drive pulley drives the magnetic drive impeller to rotate through magnetic force. The electric pulley is connected to the motor through a transmission shaft, and the motor is connected to the computer control acquisition system.

5. The device according to claim 1, characterized in that, The pressure medium temperature and pressure control system includes a sealed pressure slurry cup, a medium heating device, and a pressure medium pressure control device. The sealed pressure slurry cup includes a pressure top cover, a pressure kettle body, and a pressure bottom base. The pressure top cover and the pressure bottom base are respectively connected to the pressure kettle body through threads, and the pressure top cover and the pressure bottom base are respectively sealed with the pressure kettle body through sealing rubber rings; The medium heating device includes a third heating sleeve sleeved on the pressure kettle body, a temperature sensor f installed on the third heating sleeve, and a temperature sensor e installed on the pressure top cover. The signal output ends of the temperature sensor e, the temperature sensor f, and the third heating sleeve are respectively connected to a temperature control device, and the signal output end of the temperature control device is connected to a computer control acquisition system; The pressure medium pressure control device includes a fourth interface, a pressure medium supply container, an upper pressure device, an upper pressure sensor, and a fifth valve. The fourth interface is connected to the upper pressure device through a hydraulic pipeline, and a fifth valve is installed on this hydraulic pipeline. An upper pressure sensor is installed at the outlet of the upper pressure device. The upper pressure device is connected to the pressure medium supply container through a hydraulic pipeline and a sixth valve. The pressure medium supply container is filled with sizing water.

6. The device according to claim 1, wherein The cement slurry temperature control system includes a first heating sleeve sleeved on the test outer cylinder, a temperature sensor b installed on the first heating sleeve, a temperature sensor a installed on the test top cover, a heat transfer medium supply container, and a temperature control device. The signal output ends of the temperature sensor a, the temperature sensor b, and the first heating sleeve are respectively connected to the temperature control device, and the signal output end of the temperature control device is connected to a computer control acquisition system; The upper end of the heat transfer medium supply container is connected to a nitrogen cylinder through a gas pipeline, a three-way valve II, a three-way valve I, and a four-way valve, and is connected to a vent valve I through a gas pipeline and a three-way valve II.

7. The device according to claim 6, characterized in that, The heat transfer medium supply container is filled with a heat transfer medium. The initial boiling point of the heat transfer medium is 320 °C, the flash point is 255 °C, and the pour point is -15 °C.

8. The device according to claim 1, characterized in that, The lower-end slurry pressure monitoring system includes a lower-end pressure measurement interface, a fourth valve, a lower-end pressure sensor, and a lower-end micro-leakage container. The inside of the lower-end pressure measurement interface contains a filter element. The lower-end pressure measurement interface is connected to the lower-end micro-leakage container through a hydraulic pipeline. A fourth valve is also installed on the hydraulic pipeline. The signal acquisition end of the lower-end pressure sensor is connected to the lower-end micro-leakage container, and the signal output end is connected to the computer control and acquisition system. The lower-end micro-leakage container is filled with mixing water, and leaks at a rate of 0.001 - 0.01 cm 3 / s within a certain pressure range.

9. A test method for a test device of the pressure transmission rate during the whole hydration process of oil and gas well cement slurry, characterized in that, It includes: Step 1. Seal the test bottom base and the test top cover with the test inner cylinder through sealing rubber rings respectively, and install them on the test outer cylinder through screws; Step 2. After sealing the pressure bottom base and the pressure kettle body with a sealing rubber ring, connect them through threads. Connect the upper hydraulic interface to the test top cover through threads. The upper hydraulic interface is connected to the third interface through a hydraulic pipeline and a second valve. Connect the third interface to the pressure bottom base through threads. Close the second valve. Fill the pressure kettle body with sizing water. Connect the pressure top cover to the pressure kettle body through threads and seal it with a sealing ring; Step 3. Seal the heating base and the heating kettle body with a sealing rubber ring and connect them by threads. Connect the first interface to the test top cover by threads. Connect the first interface to the second interface through a hydraulic pipeline and a first valve. Connect the second interface to the heating base by threads. Close the first valve. Install the magnetic drive impeller in the heating kettle body. Pour the prepared cement slurry into the heating kettle body. Connect the heating top cover to the heating kettle body by threads and seal it with a sealing ring. Install the sealed bearing on the heating top cover by a buckle. The sealed bearing is sealed with the heating top cover and the magnetic drive impeller through a sealing ring. Connect the sealed cover to the heating top cover by threads and seal it with a sealing ring. Install the magnetic drive pulley outside the sealed cover and connect it to the electric pulley by a belt; Step 4. Coat the surface of the temperature sensor a with a layer of high-temperature resistant lubricating oil, insert it into the test inner cylinder and tightly connect it to the test top cover through threads and a sealing ring. The temperature sensor a is in direct contact with the cement slurry to be tested during the test. Connect the temperature sensor b to the first heating sleeve. Insert the temperature sensor c into the heating kettle body and tightly connect it to the heating kettle body through threads. Connect the temperature sensor d to the second heating sleeve. Insert the temperature sensor e into the pressurizing medium and tightly connect it to the pressurizing top cover through threads and a sealing ring. Connect the temperature sensor f to the third heating sleeve. Connect the temperature control device to the first heating sleeve, the second heating sleeve, the third heating sleeve, the temperature sensor a, the temperature sensor b, the temperature sensor c, the temperature sensor d, the temperature sensor e, the temperature sensor f and the computer control acquisition system respectively through data lines; Step 5. Fill the heat transfer medium supply container with the heat transfer medium. Connect the heat transfer medium supply container to the four-way valve through a pneumatic pipeline via a three-way valve II and a three-way valve I. Connect the heat transfer medium supply container to the atmosphere through a pneumatic pipeline via a three-way valve II and a vent valve I. Connect the upper pneumatic interface to the four-way valve through a pneumatic pipeline via a pressure reducing valve II. The upper pneumatic interface is connected to the test top cover by threads. Connect the upper annulus interface to the four-way valve through a pneumatic pipeline via a three-way valve III and a three-way valve I. The upper annulus interface is connected to the atmosphere through a three-way valve III and a vent valve II. The upper annulus interface is connected to the test top cover by threads. Connect the heating pneumatic interface to the four-way valve through a pneumatic pipeline via a first pressure reducing valve. The heating pneumatic interface is connected to the heating top cover by threads. Connect the lower annulus interface to the heat transfer medium supply container through a pipeline via a third valve. The lower annulus interface is connected to the test base by threads. Connect the four-way valve to the nitrogen cylinder through a pneumatic pipeline; Step 6. Connect one end of the lower pressure sensor to the lower micro-leakage container and the other end to the computer control acquisition system. Connect one end of the lower micro-leakage container to the lower pressure measurement interface through a hydraulic pipeline via a fourth valve and the other end to the atmosphere through a leakage pipeline. Connect the lower pressure measurement interface to the test base by threads; Step 7. Connect one end of the upper pressure sensor to the upper pressurizing device and the other end to the computer-controlled acquisition system. Connect one end of the upper pressurizing device to the fourth interface through a hydraulic pipeline via the fifth valve, and connect the other end to the pressurizing medium supply container through a hydraulic pipeline via the sixth valve. Connect the fourth interface to the pressurizing top cover by threading. Step 8. Before the experiment, ensure that all valves are closed. Open the nitrogen cylinder, four-way valve, three-way valve I, three-way valve II, third valve, three-way valve III, and vent valve II. Fill the annular space formed between the test outer cylinder and the test inner cylinder with the heat-conducting medium from the heat-conducting medium supply container. Close three-way valve III and vent valve II, and open vent valve I. Step 9. Open the fifth valve and the sixth valve, start the upper pressurizing device, set the target pressure, and use the upper pressurizing device to continuously and evenly pressurize the upper end of the pressurizing medium through the fourth interface until the target pressure is reached and the target pressure is maintained. Step 10. Open pressure-dividing valve I and use pressure-dividing valve I to control the upper-end pressure of the cement slurry to be heated during the heating process through the heating air-pressure interface. Open pressure-dividing valve II and use pressure-dividing valve II to control the pressure inside the test inner cylinder through the upper-end air-pressure interface. Step 11. Start the motor through the computer-controlled acquisition system and control the magnetic drive impeller to stir the cement slurry at a speed of 1505 r / min using the electric pulley and the magnetic drive pulley. Step 12. Turn on the temperature control device, preset the heating temperature and the heating rate, and respectively control the first heating jacket, the second heating jacket, and the third heating jacket to heat the test inner cylinder, the cement slurry to be heated, and the pressurizing medium. Turn on the computer-controlled acquisition system to record the temperatures inside the test inner cylinder, the cement slurry to be heated, and the heating medium. Step 13. After the temperature of the cement slurry to be heated rises to the preset heating temperature, open the first valve. Due to the pressure difference, the cement slurry to be heated is pressed from the heating kettle body into the test inner cylinder. Open the second valve, and use the pressurizing medium through the upper-end pressurizing device to control the upper-end pressure of the cement slurry to be tested as P1. Open the fourth valve, start the lower-end pressure sensor, and use the lower-end micro-leakage control container to control the mixing water to flow out at a constant micro-flow rate of 0.001~0.01 cm 3 / s; Step 14. Record the pressure changes at the upper and lower ends of the cement slurry to be tested through the computer-controlled acquisition system. Step 15. After the experiment, the computer-controlled acquisition system saves the experimental data. Turn off the temperature control device. After the experimental device cools down to room temperature, use the upper pressurizing device to relieve the upper-end pressure of the cement slurry to be tested. Close the upper pressurizing device, the fifth valve, and the fourth valve. Open three-way valve III to press the heat-conducting medium into the heat-conducting medium supply container. Close the nitrogen cylinder. After the air pressure of the device is completely released, close all valves, remove the pipelines of each device and the monitoring system, remove the test base and the test top cover, take out the test sample, and clean the first interface, the first valve, the second interface, the pressurizing hot seat, the heating kettle body, and the heating top cover.

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