A casing-cement sheath interface stress monitoring apparatus and method
By designing a casing-cement ring interface stress monitoring device, the stress changes during the cement slurry solidification process and under different working conditions can be monitored in real time. This solves the shortcomings of existing casing-cement ring interface stress monitoring technology and realizes accurate monitoring and optimized design under high temperature and high pressure conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTHWEST PETROLEUM UNIV
- Filing Date
- 2023-10-09
- Publication Date
- 2026-06-30
AI Technical Summary
Existing technologies struggle to directly and accurately obtain stress changes at the casing-cement sheath interface, especially given the lack of integrity monitoring devices and methods under high temperature and high pressure conditions.
A casing-cement ring interface stress monitoring device was designed, including a pressure-controlled temperature chamber, an inner casing, an outer casing, a pressure receiving device, a high-precision force sensor, and other components. The device monitors the cement slurry solidification process and the interface stress changes under different working conditions in real time, and calculates the stress using the formula σ=F/A.
It enables accurate monitoring of the cement slurry solidification process and stress changes at the casing-cement sheath interface under different working conditions, providing a theoretical basis for cement sheath integrity and well cementing optimization design.
Smart Images
Figure CN117307138B_ABST
Abstract
Description
Technical Field
[0001] This patent relates to the field of oil and gas drilling and production engineering technology, specifically a casing-cement sheath interface stress monitoring device and method. Background Technology
[0002] As my country's exploration and development focus gradually shifts from deep wells to ultra-deep wells, maintaining wellbore integrity has become crucial for the long-term safe production of oil and gas. Cement sheaths, being the weakest link in the wellbore, are highly susceptible to integrity failure under high temperature and pressure, leading to cement sheath connectivity and leakage. This results in continuous annular pressure and wellhead uplift, seriously threatening the safe production of oil and gas wells and significantly reducing their service life.
[0003] To date, domestic and international scholars primarily calculate the stress at the casing-cement sheath interface using theoretical calculations, including the initial interface stress and subsequent additional interface stresses induced by temperature and pressure. However, experimental devices and methods for directly monitoring the stress at the casing-cement sheath interface throughout the entire cycle from cement slurry solidification to subsequent changes in operating conditions are relatively scarce. Patent CN202111261276 provides an experimental device and method for testing the initial contact stress at the cement sheath interface under high temperature and high pressure. This method primarily calculates the stress at the casing-cement sheath interface indirectly by attaching strain gauges to the outer wall of the casing, and cannot directly obtain the stress changes at the casing-cement sheath interface throughout the entire cycle.
[0004] To address this technical challenge of directly and accurately obtaining the stress at the casing-cement sheath interface, this invention proposes a casing-cement sheath interface stress monitoring device and method. This method can directly and accurately obtain the stress evolution characteristics of the casing-cement sheath interface during the cement slurry solidification process and under simulated working conditions, providing a theoretical basis for the cementing mechanical properties, cement sheath integrity, and cementing optimization design of oil and gas wells. Summary of the Invention
[0005] The purpose of this invention is to provide a casing-cement sheath interface stress monitoring device and method that, while maintaining the integrity of the testing device, solves the technical problem of direct monitoring of casing-cement sheath interface stress. This method is simple to use and low in cost.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] This invention provides a casing-cement ring interface stress monitoring device, characterized in that the device includes a pressure-controlled temperature chamber, an inner casing, an annulus, an outer casing, a pressure receiving device, a high-precision force sensor, a first screw, a baffle, a pressure acquisition device, a lower end cover, a sealing ring, a base, an upper end cover, a thermocouple, a thermocouple control system, a pressure relief valve, a pressure-increasing valve, a cement ring, a first threaded hole, an annular plate, a second screw, an annular hole, a second threaded hole, a countersunk hole, sensor wiring, a round hole, an annular groove, and a square groove; wherein, the pressure-controlled temperature chamber is composed of an inner casing, a lower end cover, an upper end cover, a thermocouple, a thermocouple control system, a pressure relief valve, and a pressure-increasing valve, the pressure-increasing valve is used to control the pressure loading of the pressure-controlled temperature chamber, the pressure relief valve is used to control the pressure unloading of the pressure-controlled temperature chamber, and the thermocouple and thermocouple control system are used to control the temperature of the pressure-controlled temperature chamber; the annulus is composed of an inner casing, an outer casing, and a sealing ring, the sealing ring being used to prevent cement slurry leakage. The casing-cement sheath interface stress monitoring system consists of an outer casing, a pressure receiving device, a high-precision force sensor, a first screw, a baffle, and a second screw. It monitors the stress at the interface between the outer casing and the cement sheath. The pressure receiving device is formed by welding the ring plate and the second screw, enabling real-time sensing of pressure changes at the interface. The second screw on the pressure receiving device connects to the second threaded hole inside the high-precision force sensor, transmitting pressure from the receiving device to the sensor. The high-precision force sensor connects to the pressure acquisition device via sensor wiring to display the pressure at the interface. The first screw connects to the first threaded hole on the baffle through the countersunk hole of the high-precision force sensor, fixing the sensor in place. The base contains a round hole, an annular groove, and a square groove. The round hole and annular groove are used to position the inner and outer casings, ensuring the inner casing is centered within the outer casing. The square groove is used to fix the baffle.
[0008] Based on a casing-cement sheath interface stress monitoring device, a method for monitoring the stress at the casing-cement sheath interface is proposed. The method mainly includes the following steps:
[0009] Step 1: Apply grease to the side of the ring plate to ensure it matches the annular hole inside the outer sleeve, preventing the grout from flowing out from the gap between the ring plate and the annular hole;
[0010] Step 2: Assemble the experimental equipment, turn on the pressure acquisition device, and calibrate the high-precision force sensor;
[0011] Step 3: Based on the simulated working conditions, open the pressurization valve and thermocouple control system to raise the temperature and pressure of the pressure-controlled chamber to the curing temperature and pressure;
[0012] Step 4: Based on the actual needs on site, prepare cement grout according to standard GB / T 19139-2012, pour cement grout into the annulus for curing to form a cement ring, and monitor the interface pressure between the outer sleeve and the cement ring in real time during the cement grout solidification process.
[0013] Step 5: After the cement ring is cured and formed, the temperature and pressure in the pressure-bearing temperature control chamber are controlled by the pressure relief valve, pressure increase valve and thermocouple control system according to the simulated working conditions. The pressure at the interface between the outer tube and the cement ring under different working conditions is monitored in real time.
[0014] Step Six: After the simulation experiment is completed, close the pressurization valve and thermocouple control system, and open the depressurization valve to release the temperature and pressure of the pressure-controlled chamber;
[0015] Step 7: Collect and save monitoring data;
[0016] Step 8: Calculate the interfacial stress between the outer casing and the cement ring using the pressure monitoring data at the casing-cement ring interface and the formula σ = F / A. In the formula, σ is the interfacial stress between the outer casing and the cement ring (Pa); F is the monitored interfacial pressure between the outer casing and the cement ring (N); and A is the area of the ring plate (m²). 2 .
[0017] The present invention has the following advantages:
[0018] This invention can accurately obtain the stress changes at the casing-cement sheath interface during the cement slurry solidification process and the stress evolution law at the casing-cement sheath interface under different working conditions after the cement sheath is formed. The testing method of this invention is simple, and the test results are direct and accurate, which can provide important theoretical basis for the integrity of the cement sheath and the optimized design of cementing engineering. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 ;
[0020] Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 ;
[0021] Figure 3 This is a schematic diagram of the outer tube;
[0022] Figure 4 This is a schematic diagram of a pressure receiver;
[0023] Figure 5 This is a schematic diagram of a high-precision force sensor. Detailed Implementation
[0024] The present invention will now be described in detail with reference to the accompanying drawings.
[0025] Referring to the accompanying drawings, this invention provides a casing-cement ring interface stress monitoring device, characterized in that the device includes a pressure-controlled temperature chamber 1, an inner casing 2, an annulus 3, an outer casing 4, a pressure receiving device 5, a high-precision force sensor 6, a first screw 7, a baffle 8, a pressure acquisition device 9, a lower end cover 10, a sealing ring 11, a base 12, an upper end cover 13, a thermocouple 14, a thermocouple control system 15, a pressure relief valve 16, a pressure increasing valve 17, a cement ring 18, a first threaded hole 19, an annular plate 20, a second screw 21, an annular hole 22, a second threaded hole 23, a countersunk hole 24, and a sensor. The device includes wiring 25, round hole 26, annular groove 27, and square groove 28; wherein, the pressure-bearing temperature-controlled chamber 1 is composed of inner sleeve 2, lower end cover 10, upper end cover 13, thermocouple 14, thermocouple control system 15, pressure relief valve 16, and pressure-increasing valve 17. The pressure-increasing valve 17 is used to control the loading of pressure in the pressure-bearing temperature-controlled chamber 1, the pressure relief valve 14 is used to control the unloading of pressure in the pressure-bearing temperature-controlled chamber 1, and the thermocouple 14 and thermocouple control system 15 are used to control the temperature of the pressure-bearing temperature-controlled chamber 1; the annulus 3 is composed of inner sleeve 2, outer sleeve 4, and sealing ring 11. The sealing ring 11 is used to prevent cement slurry leakage. The casing-cement ring interface stress monitoring system consists of an outer casing 4, a pressure receiving device 5, a high-precision force sensor 6, a first screw 7, a baffle 8, and a second screw 21, enabling stress monitoring at the interface between the outer casing 4 and the cement ring 18. The ring plate 20 and the second screw 21 are welded together to form the pressure receiving device 5, enabling real-time sensing of pressure changes at the interface between the outer casing 4 and the cement ring 18. The second screw 21 on the pressure receiving device 5 is connected to the second threaded hole 23 inside the high-precision force sensor 6, allowing pressure transmission from the pressure receiving device 5 to the high-precision force sensor 6. Force sensor 6; The high-precision force sensor 6 is connected to the pressure acquisition device 9 through sensor wiring 25 to display the interface pressure between the outer sleeve 4 and the cement ring 18; The first screw 7 is connected to the first threaded hole 19 on the baffle 8 through the countersunk hole 24 inside the high-precision force sensor 6 to fix the high-precision force sensor 6; The base 12 has a round hole 26, an annular groove 27, and a square groove 28. The round hole 26 and the annular groove 27 are used to position the inner sleeve 2 and the outer sleeve 4 to achieve the centering of the inner sleeve 2 inside the outer sleeve 4; The square groove 28 is used to fix the baffle 8.
[0026] Based on a casing-cement sheath interface stress monitoring device, a method for monitoring the stress at the casing-cement sheath interface is proposed. The method mainly includes the following steps:
[0027] Step 1: Apply grease to the side of the ring plate 20 to ensure it matches the annular hole 22 inside the outer sleeve 4, preventing the cement grout from flowing out from the gap between the ring plate 20 and the annular hole 22;
[0028] Step 2: Assemble the experimental equipment, turn on the pressure acquisition device 9, and calibrate the high-precision force sensor 6;
[0029] Step 3: According to the simulated working conditions, open the pressurization valve 17 and the thermocouple control system 15 to raise the temperature and pressure of the pressure-controlled chamber 1 to the curing temperature and pressure;
[0030] Step 4: Based on the actual needs on site, prepare cement grout according to standard GB / T 19139-2012, pour cement grout into annulus 3 for curing to form cement ring 18, and monitor the interface pressure between outer sleeve 4 and cement ring 18 in real time during the cement grout solidification process.
[0031] Step 5: After the cement ring 18 is cured and formed, the temperature and pressure in the pressure-bearing temperature-controlled chamber 1 are controlled by the pressure relief valve 16, the pressure-increasing valve 17 and the thermocouple control system 15 according to the simulated working conditions, and the interface pressure between the outer tube 4 and the cement ring 18 under different working conditions is monitored in real time.
[0032] Step 6: After the simulation experiment is completed, close the pressurization valve 17 and the thermocouple control system 15, and open the pressure relief valve 16 to release the temperature and pressure of the pressure-controlled chamber 1;
[0033] Step 7: Collect and save monitoring data;
[0034] Step 8: Calculate the interfacial stress between the outer casing 4 and the cement ring 18 using the pressure monitoring data at the casing-cement ring interface and the formula σ = F / A. In the formula, σ is the interfacial stress between the outer casing 4 and the cement ring 18 (Pa); F is the monitored interfacial pressure between the outer casing 4 and the cement ring 18 (N); and A is the area of the ring plate 20 (m²). 2 .
Claims
1. A casing-cement sheath interface stress monitoring device, characterized by, The device includes a pressure-controlled temperature chamber (1), an inner sleeve (2), an annulus (3), an outer sleeve (4), a pressure receiving device (5), a high-precision force sensor (6), a first screw (7), a baffle (8), a pressure acquisition device (9), a lower end cover (10), a sealing ring (11), a base (12), an upper end cover (13), a thermocouple (14), a thermocouple control system (15), a pressure relief valve (16), a pressure increasing valve (17), a cement ring (18), a first threaded hole (19), an annular plate (20), a second screw (21), an annular hole (22), a second threaded hole (23), a countersunk hole (24), a sensor wiring (25), and a round hole (26). 6) Annular groove (27) and square groove (28); wherein, the pressure-bearing temperature-controlled chamber (1) is composed of an inner sleeve (2), a lower end cover (10), an upper end cover (13), a thermocouple (14), a thermocouple control system (15), a pressure relief valve (16) and a pressure-increasing valve (17). The pressure-increasing valve (17) is used to control the loading of pressure in the pressure-bearing temperature-controlled chamber (1), the pressure relief valve (16) is used to control the unloading of pressure in the pressure-bearing temperature-controlled chamber (1), and the thermocouple (14) and the thermocouple control system (15) are used to control the temperature of the pressure-bearing temperature-controlled chamber (1); the annulus (3) is composed of an inner sleeve (2), an outer sleeve (4) and a sealing ring (11). The sealing ring (11) is used to control the temperature of the pressure-bearing temperature-controlled chamber (1). To prevent cement slurry leakage; the casing-cement ring interface stress monitoring system consists of an outer casing (4), a pressure receiving device (5), a high-precision force sensor (6), a first screw (7), and a baffle (8), realizing stress monitoring at the interface between the outer casing (4) and the cement ring (18); the ring plate (20) and the second screw (21) are welded to form the pressure receiving device (5), realizing real-time sensing of pressure changes at the interface between the outer casing (4) and the cement ring (18); the second screw (21) on the pressure receiving device (5) is connected to the second threaded hole (23) inside the high-precision force sensor (6), realizing the pressure on the pressure receiving device (5) is transmitted to the high-precision force sensor (6). 6) The high-precision force sensor (6) is connected to the pressure acquisition device (9) through the sensor wiring (25) to realize the display of the interface pressure between the outer sleeve (4) and the cement ring (18); the first screw (7) is connected to the first threaded hole (19) on the baffle (8) through the countersunk hole (24) in the high-precision force sensor (6) to realize the fixation of the high-precision force sensor (6); the base (12) contains a round hole (26), an annular groove (27) and a square groove (28). The round hole (26) and the annular groove (27) are used to position the inner sleeve (2) and the outer sleeve (4) to realize the centering of the inner sleeve (2) in the outer sleeve (4); the square groove (28) is used to fix the baffle (8).
2. A method for monitoring the stress at the casing-cement sheath interface, comprising the apparatus of claim 1, the method mainly comprising the following steps: Step 1: Apply grease to the side of the ring plate (20) to ensure that it matches the annular hole (22) inside the outer sleeve (4) to prevent the cement grout from flowing out from the gap between the ring plate (20) and the annular hole (22); Step 2: Assemble the experimental equipment, turn on the pressure acquisition device (9), and calibrate the high-precision force sensor (6). Step 3: According to the simulated working conditions, open the pressurization valve (17) and the thermocouple control system (15) to raise the temperature and pressure of the pressure-controlled chamber (1) to the curing temperature and pressure; Step 4: Based on the actual needs of the site, prepare cement slurry according to standard GB / T 19139-2012, pour cement slurry into the annulus (3) for curing to form a cement ring (18), and monitor the interface pressure between the outer sleeve (4) and the cement ring (18) in real time during the cement slurry solidification process; Step 5: After the cement ring (18) is cured and formed, the temperature and pressure in the pressure-bearing temperature-controlled chamber (1) are controlled by the pressure relief valve (16), the pressure-increasing valve (17) and the thermocouple control system (15) according to the simulated working conditions. The interface pressure between the outer tube (4) and the cement ring (18) under different working conditions is monitored in real time. Step 6: After the simulation experiment is completed, close the pressurization valve (17) and the thermocouple control system (15), and open the depressurization valve (16) to release the temperature and pressure of the pressure-controlled chamber (1); Step 7: Collect and save monitoring data; Step eight: calculate the casing (4) and cement ring (18) interface stress by casing-cement ring interface pressure monitoring data, combined with the formula σ=F / A, in the formula, σ is the casing (4) and cement ring (18) interface stress, Pa; F is the monitoring casing (4) and cement ring (18) interface pressure, N; A is the area of the ring plate (20), m 2 .