A device and method for measuring the cementing strength of a well cementing interface before and after deformation of an ultra-high temperature and high pressure casing

Abstract

The application discloses a kind of before and after ultra-high temperature high-pressure casing deformation cementing interface cementing strength measuring device and measuring method.The structure of the device: high-temperature high-pressure kettle body is equipped with outer sleeve and inner sleeve, kettle body and outer sleeve fit, annular cavity formed between two sleeves is used as cement slurry annular cavity chamber;Inner sleeve is equipped with heating device;Temperature control system is used to heat cement slurry annular cavity chamber;Pressure control system is used to apply pressure to cement slurry annular cavity chamber;Interface cementing strength test system is used to determine the cementing strength between two sleeves and cement sheath.The application can simulate the high-temperature high-pressure maintenance conditions of cement slurry under stratum in the cementing process of oil and gas well, and test and study the first interface cementing strength between casing and cement stone after deformation under the coupling effect of high temperature and high pressure and cement hydration heat release after cementing is completed, and the first interface cementing strength between casing and cement stone without deformation.

Description

Technical Field

[0001] This invention relates to a measuring device and method for measuring the bonding strength of the cementing interface before and after deformation of ultra-high temperature and high pressure casing, belonging to the field of oil and gas well cementing engineering technology. Background Technology

[0002] Cementing in oil and gas wells involves using cement to effectively bond and seal the annular space between the casing and the formation. Its main functions are to isolate oil, gas, and water layers, reinforce the wellbore, and prevent interlayer flow of underground fluids. The quality of cementing depends primarily on the bonding strength between the cement paste and the casing / formation interface.

[0003] The bonding strength of the cement stone interface in well cementing is mainly divided into the first bonding interface between the cement sheath and the casing, and the second bonding interface between the cement sheath and the formation. If the bonding strength of the interface is low, the extreme and complex environment faced by oil and gas wells during operation, such as high temperature and high pressure, can easily cause the sealing effect of the cement sheath to fail, resulting in well cementing accidents such as oil and gas channeling at the bonding interface, affecting oil and gas production and well life.

[0004] Current research on the interfacial bonding strength in downhole operations mainly focuses on the bonding strength of the first interface between cement stone and casing (Luo Changji, Wang Yunliang, Zhang Bin. Experimental study on the interfacial bonding strength of cementing annulus [J]. Petroleum Drilling and Production Technology, 1993(03):47-51.), but there is little research on the influence of casing deformation under high temperature and high pressure inside the formation on the bonding strength of the first interface; secondly, the experimental research method for the bonding strength of cementing annulus is mainly mechanical testing, that is, first curing under certain temperature and pressure, and then taking out the sample and testing it with a pressure resistance instrument (Song Meimei, Guan Zhengrong. Sulfoaluminate water The effect of mud expansion properties on the bonding strength of cementing interface [J]. Cement, 2019(09):10-13.) The experimental method for bonding strength of cement stone interface has the characteristics of low error tolerance and inflexibility; most importantly, a large number of experimental studies have not considered that the large amount of heat released by cement hydration under high temperature and high pressure conditions will further cause casing deformation (Zhang Wandong, Li Yanjun, Wu Jiang, Yang Yuhao, Yang Huanqiang. Experimental study on hydraulic bonding strength of cementing first interface under high temperature conditions [J]. Drilling and Production Technology, 2019, 42(05):24-26+7.), thus affecting the bonding strength of the first interface, and has not directly tested the amount of casing deformation in this process.

[0005] Therefore, it is urgent to develop a device and testing method to simulate the bonding strength of the cement interface before and after casing deformation under the coupled effect of high temperature and high pressure downhole and the exothermic effect of cement hydration, so as to more scientifically test and compare the bonding strength of the cement stone at the first interface before and after casing deformation. Summary of the Invention

[0006] The purpose of this invention is to provide a measuring device and method for measuring the cementing strength of the cementing interface before and after the deformation of ultra-high temperature and high pressure casing. This invention has a reliable principle, reasonable structure, flexible testing process, and high fault tolerance. It can simultaneously meet the requirements of high temperature and high pressure curing of cement stone and scientific testing and comparison of the first interface cementing strength and differences of cement stone before and after casing deformation.

[0007] The device for measuring the cementing strength of the cementing interface before and after deformation of ultra-high temperature and high pressure casing provided by the present invention includes a high temperature and high pressure vessel mold, a temperature control system, a pressure control system, and an interface cementing strength testing system.

[0008] The high-temperature and high-pressure reactor mold includes a high-temperature and high-pressure reactor body, a reactor lid, and a reactor bottom, wherein the reactor lid and the reactor bottom are respectively fitted to both ends of the high-temperature and high-pressure reactor body;

[0009] The high-temperature and high-pressure reactor body is fitted with an outer sleeve and an inner sleeve. The high-temperature and high-pressure reactor body is fitted with the outer sleeve. The annular cavity formed between the outer sleeve and the inner sleeve serves as a cement slurry annular cavity. A heating device is installed inside the inner sleeve.

[0010] The cement slurry annular cavity is used to fill cement slurry and forms a pressurized chamber at the upper end. A pressure relief safety valve is provided at the top of the pressurized chamber.

[0011] The temperature control system is used to heat the cement slurry annular cavity.

[0012] The pressure control system is used to apply pressure to the cement slurry annular cavity.

[0013] The interface bonding strength testing system is used to determine the bonding strength between the outer sleeve and the inner sleeve and the cement ring in the cement grout ring cavity.

[0014] In the aforementioned measuring device, the high-temperature and high-pressure vessel body is connected to the vessel bottom by bolts;

[0015] The high-temperature and high-pressure vessel body and the vessel cover are connected by bolts, and the vessel cover is also connected to a sleeve plug by bolts. The high-temperature and high-pressure vessel body, the vessel cover, the sleeve plug and the inner sleeve form the pressurization chamber.

[0016] The upper end of the inner sleeve is connected to the sleeve plug.

[0017] In the aforementioned measuring device, a high-temperature resistant rubber ring is provided between the high-temperature and high-pressure reactor body and the outer sleeve to prevent damage to the reactor body caused by the expansion effect under high pressure, and to prevent deformation of the outer sleeve. It should be noted that the outer sleeve and the inner sleeve are made of the same material, and the difference in cement-stone bonding strength is only affected by whether the sleeve is deformed and the degree of deformation.

[0018] In the aforementioned measuring device, the temperature control system includes a heating tube disposed within the inner sleeve;

[0019] The heating element is connected to the heating controller, and the heating controller is connected to the control panel. The control panel controls the heating controller to heat the heating element.

[0020] In the aforementioned measuring device, the pressure control system includes an air compressor pump, which is mainly used to apply pressure to the end face of the cement slurry. The entire system is closely connected to control the experimental pressure.

[0021] The air compressor pump is connected to the pressurization chamber via a pipeline equipped with a pressurization safety valve and a pressurization pressure gauge.

[0022] In the aforementioned measuring device, the interface bonding strength testing system includes an inner sleeve bonding strength hydraulic propulsion unit and an outer sleeve bonding strength hydraulic propulsion unit. It uses the principle of hydraulic propulsion to test the interface bonding strength, and the maximum reading of the pressure gauge is the maximum bonding strength value.

[0023] Both the inner sleeve bonding strength hydraulic propulsion unit and the outer sleeve bonding strength hydraulic propulsion unit are connected to a hydraulic bonding strength testing machine, and the connected pipelines are equipped with a bonding strength testing pressure gauge and a safety valve.

[0024] In the aforementioned measuring device, the pressurization chamber is equipped with a temperature sensor and a pressure sensor to monitor the curing temperature and curing pressure, respectively.

[0025] The temperature sensor, the pressure sensor, and the hydraulic bonding strength tester are all connected to the control panel.

[0026] The aforementioned measuring device further includes a cement hydration heat release testing system, comprising a copper sleeve and a hydration heat thermocouple connected in sequence.

[0027] The hydration thermocouple is connected to the control panel;

[0028] The hydration thermocouple and the vessel lid can be provided with a threaded connection;

[0029] The copper sleeve can extend into the cement slurry annular cavity, where the real-time temperature of the cement slurry is conducted, and the temperature data is collected by the hydration thermocouple and transmitted to the control panel.

[0030] The cement hydration heat release test system is used to monitor in real time whether the hydration heat release of cement slurry will cause or aggravate the decrease in bonding strength. Under high temperature conditions, the cement itself has a high degree of hydration. For example, the hydration temperature rise of silicate oil well cement can reach 40°C under these high temperature conditions, while aluminate oil well cement can theoretically reach 80°C. The high temperature rise may also cause the casing to deform, resulting in a decrease in the bonding strength between the cement sheath and the casing.

[0031] The measuring device described above further includes a digital micrometer for measuring the dimensions of the inner sleeve.

[0032] The digital micrometer is connected to the control panel;

[0033] The digital micrometer monitors the inner sleeve dimensions in real time and then transmits the data to the control panel.

[0034] The control panel is connected to the computer.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) It can accurately simulate the composition of underground working conditions during cementing, and the device is resistant to high temperature and high pressure, and can vividly simulate the thickening, hardening and curing conditions of cement slurry.

[0037] (2) The test content is comprehensive and can simultaneously meet the requirements of accurate curing conditions, test the heat release of cement under high temperature conditions and test the deformation of the sleeve.

[0038] (3) The test results are comprehensive and can simultaneously measure the bonding strength of the first interface after the casing is deformed and the bonding strength of the first interface before the casing is not deformed.

[0039] (4) It has good comparability and can directly compare the difference in the first interface bonding strength between casing deformation and other conditions to judge the cementing quality of the cement slurry system.

[0040] (5) It can monitor whether the casing is deformed in real time and test the hydration heat release of cement grout under high temperature conditions;

[0041] (6) The device structure is designed to be safe and reliable.

[0042] This invention can be used to simulate the high-temperature and high-pressure curing conditions of cement slurry under formation during the cementing process of oil and gas wells, and to test and study the bonding strength of the first interface between the casing and cement stone after deformation due to the coupling effect of high temperature and high pressure and the exothermic reaction of cement hydration inside the formation after cementing, as well as the bonding strength of the first interface between the casing and cement stone before deformation. It is especially suitable for the bonding strength of the cementing interface under some high-temperature and high-pressure formations, and can effectively avoid engineering accidents caused by low bonding strength due to casing deformation, which would affect the mining operation. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the device for simulating the bonding strength of the cement interface before and after casing deformation under the coupled effect of downhole high temperature and high pressure and cement hydration heat release.

[0044] The markings in the diagram are as follows:

[0045] 1—High-temperature and high-pressure reactor body; 2—High-temperature resistant rubber ring; 3—Outer sleeve; 4—Cement slurry annular cavity; 5—Inner sleeve; 6—Heating tube; 7—Reactor bottom; 8—High-strength bolts at reactor bottom; 9—Outer sleeve bonding strength hydraulic propulsion unit; 10, 11, 13, 14—Safety valves; 12—Heating controller; 15—Inner sleeve bonding strength hydraulic propulsion unit; 16—Copper sleeve; 17—Pressure chamber; 18—Digital micrometer; 19—Inner sleeve plug high-strength bolt; 20—Hydrogenation thermocouple; 21—Appetizer body pressure sensor; 22—Appetizer body temperature sensor; 23—Pressure relief valve; 24—Inner sleeve plug; 25—Appetizer body and lid high-strength bolt; 26—Appetizer lid; 27—Pressure booster safety valve; 28—Air compressor pump; 29—Pressure booster gauge; 30—Hydraulic strength testing machine; 31—Control panel; 32—Computer; 33—Bond strength testing pressure gauge. Detailed Implementation

[0046] The present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited to the following embodiments.

[0047] like Figure 1 The diagram shows the structure of the device provided by the present invention for simulating the cementing strength of the cement interface before and after casing deformation under the coupled effect of high temperature and high pressure downhole and cement hydration heat release. It mainly includes a high temperature and high pressure vessel mold, a system for simulating cementing conditions, a pressure control system, a hydraulic propulsion unit for cementing strength, a control panel 31 for testing the casing deformation caused by cement hydration heat release, and a casing deformation measurement system.

[0048] like Figure 1As shown, the high-temperature and high-pressure reactor mold is a hollow design, including a high-temperature and high-pressure reactor body 1, a reactor lid 26, a sleeve plug 24, a reactor bottom 7, and a high-temperature resistant rubber ring 2. The reactor lid 26 is connected to the high-temperature and high-pressure reactor body 1 by high-strength bolts 25, and the sleeve plug 24 is connected to the reactor lid 26 by high-strength bolts 19. The reactor bottom 7 is connected to the high-temperature and high-pressure reactor body 1 by high-strength bolts 8. The high-temperature and high-pressure reactor body 1 is fitted with an outer sleeve 3 and an inner sleeve 5. A high-temperature resistant rubber ring 2 is provided between the outer sleeve 3 and the high-temperature and high-pressure reactor body 1. The annular cavity formed between the outer sleeve 3 and the inner sleeve 5 serves as a cement slurry annular cavity 4, used to fill the cement slurry. The high-temperature and high-pressure reactor body 1, reactor lid 26, sleeve plug 24, and inner sleeve 5 form a pressurization chamber.

[0049] In the measuring device of this invention, the materials used for the outer casing 3 and the inner casing 5 are determined by the materials used in the oil well site, and both ends are fixed by casing plugs 24, bottom 7, and a hydraulic propulsion unit for bonding strength. The cement slurry annular cavity 4 is filled with a first-line oil and gas well cementing slurry system. The high-temperature resistant rubber ring 2 is designed to prevent damage to the vessel body caused by the expansion effect under high pressure, and to prevent deformation of the outer casing 3.

[0050] like Figure 1 As shown, the pressure control system includes an air compressor pump 28, which is mainly used to apply pressure to the end face of the cement slurry. The entire system is closely connected to control the experimental pressure. A pressure boosting safety valve 27 and a pressure boosting gauge 29 are installed on the pipeline connecting the air compressor pump 28 to the pressure boosting chamber. The air compressor pump 28 is connected to the control panel 31.

[0051] like Figure 1 As shown, the interface bonding strength testing system includes an inner sleeve bonding strength hydraulic propulsion unit 15 and an outer sleeve bonding strength hydraulic propulsion unit 9. It utilizes the principle of hydraulic propulsion to test the interface bonding strength, with the maximum reading on the pressure gauge representing the maximum bonding strength value. Both the inner sleeve bonding strength hydraulic propulsion unit 15 and the outer sleeve bonding strength hydraulic propulsion unit 9 are connected to a hydraulic bonding strength testing machine 30. The connected pipelines are equipped with a bonding strength testing pressure gauge 33 and safety valves (10, 11, 13, and 14). The hydraulic bonding strength testing machine 30 is connected to a control panel 31.

[0052] like Figure 1 As shown, the measuring device of the present invention also includes a cement hydration heat release testing system, including a copper sleeve 16 and a hydration heat thermocouple 20. The copper sleeve 16 extends into the cement slurry to conduct the real-time temperature of the cement slurry. The temperature data is collected by the hydration heat thermocouple 20 and transmitted to the control panel 31 and the computer 32 to monitor in real time whether the hydration heat release of the cement slurry will cause or aggravate the decrease in bonding strength.

[0053] like Figure 1As shown, the measuring device of the present invention is also equipped with a digital micrometer 18, which is connected to the control panel 31. The digital micrometer 18 monitors the size of the inner sleeve 5 in real time and then transmits the data to the control panel 31 and the computer 32.

[0054] The above-mentioned device was used to simulate the cement interface bonding strength test after casing deformation under downhole operating conditions. The specific test process is as follows:

[0055] Apply oil to all threaded parts, close all valves, open the lid 26 and sleeve plug 24 of the high-temperature and high-pressure reactor body 1, install the high-temperature resistant rubber ring 2 into the predetermined position inside the reactor body, install the lower and upper reactor bottoms 7, and tighten the high-strength bolts at the reactor bottom. Embed the outer sleeve 3 and inner sleeve 5 into the reactor body, check the bonding strength test to ensure the hydraulic propulsion unit is in the predetermined position, pour cement slurry into the cement slurry annular cavity 4, install the lid 26 and the sleeve deformation digital micrometer 18, insert the copper sleeve 16 into the cement slurry, and install the hydration thermocouple 20. Add appropriate amounts of heat transfer oil to the end-face pressurization chamber to prevent the cement slurry from boiling under high pressure. Install the sleeve plug 24 sequentially, tighten the high-strength bolts of the inner sleeve plug, install the reactor body pressure sensor 21 and reactor body temperature sensor 22, and tighten their bolts. Tighten the bolts on the heating controller 12 to ensure the heating control unit is installed correctly. The initial reading of the sleeve deformation was taken using a digital micrometer 18 in preparation for the experiment.

[0056] Turn on the computer 32 and control panel 31. Open the pressure boosting safety valve 27, and use the control panel 31 and air compressor 28 to pressurize the inside of the vessel. Turn on the heating tube 6, and use the control panel 31 and heating controller 12 to perform heating treatment for cement stone curing. Use the vessel temperature sensor 22 and hydration thermocouple 20 to collect the temperature of the cement stone in real time (the vessel temperature sensor 22 monitors the curing temperature in real time, and the hydration thermocouple 20 monitors the internal temperature of the cement stone in real time) to test its high-temperature hydration heat release.

[0057] After curing is complete, turn off the air compressor 28 and the pressure boosting safety valve 27. Use the pressure relief safety valve 23 to slowly release pressure. Monitor the real-time temperature of the vessel using the control panel 31, and begin the bonding strength test once the temperature drops below 93°C.

[0058] Close safety valves 11 and 13, open safety valves 10 and 14, and turn on the hydraulic strength testing machine 30. Use the outer sleeve bonding strength hydraulic propulsion unit 9 to test the bonding strength. The maximum pressure gauge reading represents the bonding strength between the undeformed sleeve and the cement ring. After the test, the hydraulic strength testing machine 30 returns to its original position, and safety valves 10 and 14 are closed. Unscrew the bolts on the hydration thermocouple 20, open safety valves 11 and 13, and turn on the hydraulic strength testing machine 30. Use the inner sleeve hydraulic propulsion unit 15 to test the bonding strength. The maximum pressure gauge reading represents the bonding strength between the undeformed sleeve and the cement ring. After the test, the hydraulic strength testing machine 30 returns to its original position, and safety valves 11 and 13 are closed. Test complete.

[0059] Close the control panel 31, shut down the computer 32. Disassemble and clean the instrument.

[0060] The experiment is over.

[0061] The cement bond strength test results after casing deformation under simulated downhole conditions using the above-mentioned device are shown in Tables 1 and 2. Table 1 shows the cement slurry composition as follows: 100% Grade G oil well cement + 1.5% G33S (fluid loss reducer) + 0.5% SXY-2 (dispersant) + 45% water, which is a pure cement slurry without any admixtures. Table 2 shows the cement slurry composition as follows: 100% Grade G oil well cement + 10% DRB-2S (toughening material) + 10% quartz sand + 4% microsilica + 1.5% G33S (fluid loss reducer) + 0.5% SXY-2 (dispersant) + 45% water, which is a toughened cement slurry. The data in Tables 1 and 2 show that:

[0062] 1. The increase in temperature and pressure during slurry hydration allows the cement slurry to release more heat, deepening the hydration process and causing greater deformation of the casing. Furthermore, the deeper hydration process increases the bonding strength between the casing and the cement ring.

[0063] 2. The addition of toughening materials and the reduction of casing deformation can improve the bonding strength of the cement ring-casing interface.

[0064] Table 1 shows the cement interface strength of pure cement stone before and after casing deformation, tested using the device of the present invention.

[0065]

[0066] Table 2 shows the cementing strength of the toughened cement stone at the cementing interface before and after casing deformation, tested using the device of the present invention.

[0067]

Claims

1. A measuring device for cementing interface strength of ultra-high temperature and high pressure casing before and after deformation, comprising a high temperature and high pressure vessel mold, a temperature control system, a pressure control system and an interface cementing strength testing system; The high-temperature and high-pressure reactor mold includes a high-temperature and high-pressure reactor body, a reactor lid, and a reactor bottom, wherein the reactor lid and the reactor bottom are respectively fitted to both ends of the high-temperature and high-pressure reactor body; The high-temperature and high-pressure reactor body is fitted with an outer sleeve and an inner sleeve. The high-temperature and high-pressure reactor body is fitted with the outer sleeve. The annular cavity formed between the outer sleeve and the inner sleeve serves as a cement slurry annular cavity. A heating device is installed inside the inner sleeve. The cement slurry annular cavity is used to fill cement slurry and forms a pressurized chamber at the upper end. A pressure relief safety valve is provided at the top of the pressurized chamber. The temperature control system is used to heat the cement slurry annular cavity. The pressure control system is used to apply pressure to the cement slurry annular cavity. The interface bonding strength testing system is used to determine the bonding strength between the outer sleeve and the inner sleeve and the cement ring in the cement grout ring cavity. The temperature control system includes a heating tube disposed inside the inner sleeve; The heating element is connected to the heating controller, and the heating controller is connected to the control panel; The pressure control system includes an air compressor pump; The air compressor pump is connected to the booster chamber via a booster safety valve and a booster pressure gauge. The interface bonding strength testing system includes an inner sleeve bonding strength hydraulic propulsion unit and an outer sleeve bonding strength hydraulic propulsion unit. Both the inner sleeve bonding strength hydraulic propulsion unit and the outer sleeve bonding strength hydraulic propulsion unit are connected to a hydraulic bonding strength tester, and the connected pipelines are equipped with a bonding strength test pressure gauge and a safety valve. The pressurization chamber is equipped with a temperature sensor and a pressure sensor; The temperature sensor, the pressure sensor, and the hydraulic bonding strength tester are all connected to the control panel. The measuring device also includes a cement hydration heat release testing system, comprising a copper sleeve and a hydration heat thermocouple connected in sequence; The hydration thermocouple is connected to the control panel; The copper sleeve extends into the cement slurry annular cavity; The measuring device also includes a digital micrometer for measuring the dimensions of the inner sleeve; The digital micrometer is connected to the control panel; The control panel is connected to the computer; The high-temperature and high-pressure vessel body and the vessel cover are connected by bolts, and the vessel cover is also connected to a sleeve plug by bolts. The high-temperature and high-pressure vessel body, the vessel cover, the sleeve plug and the inner sleeve form the pressurization chamber.

2. The measuring device according to claim 1, characterized in that: The high-temperature and high-pressure reactor body is connected to the reactor bottom by bolts; The upper end of the inner sleeve is connected to the sleeve plug.

3. The measuring device according to claim 1 or 2, characterized in that: A high-temperature resistant rubber ring is provided between the high-temperature and high-pressure reactor body and the outer sleeve.

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