CN209945889U - Reliability testing device for rubber cylinder under corrosion and stress action - Google Patents

Abstract

A reliability testing device of a rubber cylinder under the action of corrosion and stress is characterized in that: the device consists of a central shaft, a nut, a pressure ring, a packer rubber cylinder, a test sleeve, a square block, a concentric circle bottom plate, a high-temperature strain gauge, a high-temperature lead and a strain gauge; the testing device is assembled and then placed in a high-temperature high-pressure autoclave, and the contact stress between the packer rubber cylinder and the testing sleeve under various working conditions can be tested by setting the temperature, the pressure and the corrosion medium of the high-temperature high-pressure autoclave, so that the change rule of the contact stress between the packer rubber cylinder and the sleeve in the corrosion process of the packer rubber cylinder is obtained; the corrosion resistance and the sealing performance of the packer rubber cylinder in a corrosive medium environment under a stress state can be tested simultaneously, and the reliability of the packer rubber cylinder is further evaluated.

Description

A reliability testing device for rubber cartridges under the action of corrosion and stress

technical field

The utility model belongs to the technical field of petroleum equipment, in particular to a reliability testing device for a rubber cylinder under the action of corrosion and stress.

Background technique

Packer is a very important downhole device in the process of oil and gas field development. In the process of well completion, reservoir reconstruction, and layered production, the production layer is isolated by the radial deformation of the packer rubber cylinder under load. The packer is composed of steel parts and rubber barrels, and the tightness of the rubber barrels is very important for construction safety and well structure. In the process of acidification or production, the high temperature and high pressure construction working fluid or formation fluid will corrode and damage the packer rubber cylinder to a certain extent, which will lead to the failure of the packer and the destruction of the integrity of the wellbore. Therefore, simulating the corrosion of the packer rubber cylinder by the test fluid under high temperature and high pressure, and clarifying the relationship between the contact pressure and the sealing performance between the packer rubber cylinder and the test casing during the corrosion process, are of great significance to the selection and protection of the packer rubber cylinder. important meaning.

At present, the simulation test of the packer cartridge in the high temperature and high pressure environment is the foundation and an important part of the packer reliability research, but because the performance of the packer cartridge is not only affected by high temperature and high pressure, but also by the complex fluid Environmental impact, in addition, when the packer rubber cylinder is working, it is in a state of stress, which greatly increases the difficulty of the simulation test. At present, there are many devices to study the sealing performance of the packer cartridge under high temperature and high pressure, but the influence of the corrosive medium on the packer cartridge is ignored, and the device is complicated and the experiment cost is high, which is not convenient for the reliability test of the packer cartridge .

Aiming at the limitations of the current packer rubber cartridge testing device, a reliability testing device for the rubber cartridge under the action of corrosion and stress is proposed. The contact stress between the cylinder and the test casing is obtained, and the relationship between the contact stress and the experimental time is obtained; CN102654446B), the corrosion resistance and sealing performance of the packer rubber cylinder under stress state can be tested at the same time, which provides a reference for the optimal material selection and protection of the packer rubber cylinder.

Utility model content

The purpose of this utility model is to provide a reliability testing device for rubber cylinder under the action of corrosion and stress, so as to test the contact stress between the packer rubber cylinder and the casing under different corrosive environments, and obtain the difference between the contact stress and the experimental time. The relationship curve of the packer can be obtained to obtain the change law of the contact stress between the packer and the casing during the corrosion process of the packer. Provides reference for optimal material selection and protection of rubber cartridges.

The utility model adopts the following technical scheme: a reliability testing device for a rubber cylinder under the action of corrosion and stress, which is characterized in that: the device consists of a central shaft, a nut, a pressure ring, a packer rubber cylinder, a test sleeve, a square Block, concentric bottom plate, high temperature strain gauge, high temperature wire, strain gauge;

_The upper part of the central shaft is provided with a male thread, the middle part is _a smooth rod, and the lower part is provided with a step with _a height of 20mm. The thickness of the cylinder L1 is _10-15mm larger;

The stepped surface of the central axis and the pressure ring are provided with chamfers, and the thickness L ₂ of the pressure ring is 40-50 mm; the outer diameter d ₄ of the rubber cylinder of the packer is 3-5 mm smaller than the inner diameter d ₃ of the test casing;

The test sleeve and the concentric bottom plate are connected by the welding seam A; the concentric circular bottom plate and the central axis are connected by the welding seam B; the central axis and the square block are connected by the welding seam C;

There are 8 high temperature strain gauges in total, which are evenly pasted at the distance L from the bottom end of the test sleeve at an interval of 45 degrees. where L is calculated as follows:

In the formula: L is the height from the bottom end of the test casing, mm; L ₁ is the thickness of the packer rubber cylinder; L ₃ is the compression moment of the packer rubber cylinder when it is loaded;

The nut is matched with the central shaft through threads, and the nut is rotated downward to apply pressure to the packer rubber cylinder through the pressure ring to form setting; the packer rubber cylinder is connected with the central shaft and the test casing after setting. , The concentric circular bottom plate forms a sealed cavity, and a display agent is placed in the sealed cavity; the test device is assembled and placed in a high-temperature autoclave.

The beneficial effects of the present utility model are:

(1) Simulate the working conditions of the packer rubber tube when it is in service in the well, and can test the contact stress between the packer rubber tube and the test casing in various corrosive environments, and obtain the packer during the corrosion process of the packer rubber tube. The variation law of the contact stress between the rubber cylinder and the casing; the corrosion resistance and sealing performance of the packer rubber cylinder under the stress state in the corrosive medium environment can be tested at the same time;

(2) Simple structure, easy processing and easy assembly: after the packer rubber cylinder is placed on the central axis, the pressure can be loaded by tightening the nut to simulate setting; Safety guarantee, improve the safety of simulation experiments.

Description of drawings

1 is a schematic structural diagram of the packer rubber cylinder in the test device of the present invention when it is not set.

2 is a schematic structural diagram of the packer rubber cylinder after setting in the testing device of the present utility model.

FIG. 3 is a dimension diagram of each component in the testing device of the present invention.

4 is a schematic top view of the test sleeve in the test device of the present invention.

5 is a schematic top view of a square block in the testing device of the present invention.

In the picture: 1- Center shaft, 2- Nut, 3- Pressure ring, 4- Packer rubber barrel, 5- Ring barrel, 6- Weld point A, 7- Weld point B, 8- Weld point C, 9- Square block, 10-concentric bottom plate, 11-high temperature strain gauge, 12-high temperature wire, 13-strain gauge, 14-sealed cavity, 15-display agent, 16-high temperature autoclave.

Detailed ways

The present utility model will be described in detail below with reference to the accompanying drawings.

The utility model simulates the service condition of the packer rubber cylinder through a high temperature and autoclave, and tests the corrosion resistance of the packer rubber cylinder when it is set in a corrosive medium environment; the packer rubber cylinder is loaded by tightening the nut to simulate the packer rubber cylinder. For the stress state during downhole setting, the strain gauge is used to test the contact stress between the casing and the packer rubber cylinder, and the sealing performance of the packer rubber cylinder during the corrosion process is tested with a display agent.

As shown in FIG. 1, in order to use the above method, the present utility model provides a reliability testing device for a rubber cylinder under the action of corrosion and stress, which mainly includes a central shaft 1, a nut 2, a pressure ring 3, and a packer rubber cylinder 4. Test sleeve 5 , square block 9 , concentric bottom plate 10 , high temperature strain gauge 11 , high temperature wire 12 , strain gauge 13 .

The upper part of the central shaft 1 is provided with a male thread, the middle part is a smooth rod, the lower part is provided with steps and the height is 20mm, the diameter d1 of the male thread is 4-5mm smaller than the diameter _{d2 of} the smooth rod, and the length _h1 of the smooth rod is smaller than that of the isolation The thickness L1 of the packer rubber tube 4 is 10-15mm larger; the stepped surface of the central axis ₁ and the pressure ring 3 are provided with chamfers, and the thickness L2 of the pressure ring ₃ is 40-50mm; The diameter _d4 is 3-5mm smaller than the inner diameter _d3 of the test sleeve 5; the packer rubber cylinder 4 forms a sealing cavity 14 with the central shaft 1, the test sleeve 5, and the concentric bottom plate 10 after setting, and after the sealing A display agent 15 is placed in the cavity 14; the test device is assembled and placed in a high-temperature autoclave 16; a total of 8 high-temperature strain gauges 11 are uniformly pasted on the bottom end of the test sleeve 5 at intervals of 45 degrees At L, the high-temperature strain gauge 11 is connected to the external strain gauge 13 through the high-temperature wire 12, and the high-temperature strain gauge 11 and the high-temperature wire 12 are encapsulated with corrosion-resistant materials; the test sleeve 5 and the concentric bottom plate 11 are connected by the welding seam A; The concentric circular bottom plate 11 and the central axis 1 are connected by the welding seam B; the central axis 1 and the square block 9 are connected by the welding seam C.

The testing method and device provided by the utility model are used to conduct contact stress and corrosion testing on a compression packer rubber cylinder serving in the corrosive medium of hydrogen sulfide and carbon dioxide. The specific testing process includes the following steps:

Step 1: Attach high temperature strain gauges 11 at intervals of 45 degrees from the bottom end L of the test sleeve 5, and connect the high temperature strain gauges 11 to the strain gauges 13 through the high temperature wires 12, as shown in Fig. 1 and Fig. 4 ;

Step 2: Fix the square block 9, put the display agent 15 in the space formed by the test sleeve 5 and the concentric bottom plate 10, insert the packer rubber cylinder 4 into the central shaft 1, and tighten the nut 2 to press The ring 3 moves downward to compress the packer rubber cylinder 4, the packer rubber cylinder 4 radially expands and deforms and contacts the inner wall of the test casing 5, and the compression stops when the compression torque set by the packer rubber cylinder 4 stops, as shown in the attached figure 2 shown;

Step 3: Collect the circumferential strain ε _i of the outer wall of the test casing 5 by the strain gauge 13 , and calculate the contact stress P _i between the test casing 5 and the packer rubber cylinder 4 after the packer rubber cylinder 4 is compressed:

Step 4: Put the compressed test device into a high-temperature autoclave 16 filled with a corrosive medium, as shown in FIG. 2 . After deoxygenation in the high-temperature autoclave 16, the temperature is raised to the experimental preset temperature, and the preset content of carbon dioxide, hydrogen sulfide gas, and nitrogen gas is introduced to increase the pressure to the experimental preset pressure, and the heat preservation and pressure preservation corrosion experiment is carried out;

Step 5: During the corrosion test process, obtain the contact stress _Pi during the corrosion test process according to the method described in Step 3, draw the relationship curve between the contact stress _Pi and the test time, and observe the variation law of the contact stress with the test time;

Step 6: After 72 to 168 hours of the experiment, take out the test device, clean the upper liquid of the packer rubber cylinder 4, and then take out the packer rubber cylinder 4. Measure the rebound amount of the packer rubber cylinder 4, observe the deformation and morphology of the packer rubber cylinder 4, and evaluate the corrosion resistance of the packer rubber cylinder 4;

Step 7: Take out the display agent 15, and evaluate the sealing performance of the packer rubber cylinder 4 under the stress state in the high temperature and high pressure corrosion environment; and combine the relationship between the contact stress and the experimental time to demonstrate the accuracy of the results of the display agent 15;

Step 8: If the relationship curve between the display agent 15, the contact stress and the experimental time all show that the seal of the packer rubber cylinder 4 fails, then the corrosion evaluation of the test sleeve 5 is carried out: a. The test sleeve 5 is cut open, and the inner wall is observed. Corrosion macro-morphology; b. Cut a steel sheet sample at the setting contact between the test sleeve 5 and the packer rubber cylinder 4, use a scanning electron microscope and an energy dispersive spectrometer to observe the corrosion micro-morphology of the inner wall of the test sleeve 5, and clean the test sleeve. film, use a super-depth-of-field three-dimensional microscope to measure the three-dimensional morphology and corrosion depth of the inner wall of the test sleeve 5; c. scrape the inner wall corrosion product, use X-ray photoelectron spectroscopy, X-ray diffractometer to analyze the corrosion environment of the test sleeve 5. Corrosion products; d. Comprehensively analyze the corrosion effect of the failure of the packer rubber cylinder 4 on the test casing 5.

Claims (1)

1. The utility model provides a packing element is at reliability test device under corruption and stress action which characterized in that: the method mainly comprises the following steps: the device comprises a central shaft (1), a nut (2), a pressure ring (3), a packer rubber cylinder (4), a test sleeve (5), a square block (9), a concentric circle bottom plate (10), a high-temperature strain gauge (11), a high-temperature lead (12) and a strain gauge (13);

the upper part of the central shaft (1) is provided with male threads, the middle part is provided with a smooth rod, the lower part is provided with a step with the height of 20mm, and the diameter d of the male threads₁Diameter d of smoother rod₂4-5 mm small and smooth rod length h₁Is thicker than the thickness L of a packer rubber cylinder (4)₁10-15 mm in size;

the step surface of the central shaft (1) and the pressure ring (3) are provided with chamfers, and the thickness L of the pressure ring (3)₂40-50 mm; the outer diameter d of the packer rubber cylinder (4)₄Inner diameter d of the casing (5) to be tested₃The size is 3-5 mm;

the test sleeve (5) is connected with the concentric circle bottom plate (10) through a welding seam A (6); the concentric circle bottom plate (10) is connected with the central shaft (1) through a welding seam B (7); the central shaft (1) is connected with the square block (9) through a welding seam C (8);

the high-temperature strain gauges (11) are 8 in number and are uniformly adhered to the position L away from the bottom end of the test sleeve (5) at intervals of 45 degrees, the high-temperature strain gauges (11) are externally connected with a strain gauge (13) through high-temperature leads (12), and the high-temperature strain gauges (11) and the high-temperature leads (12) are packaged by using corrosion-resistant materials;

in the formula: l is the height from the bottom end of the test sleeve (5) in mm; l is₁The thickness of the packer rubber cylinder (4); l is₃A compression moment when the packer rubber cylinder (4) is loaded;

the nut (2) is matched with the central shaft (1) through threads, and the nut (2) is rotated downwards to apply pressure to the packer rubber sleeve (4) through the compression ring (3) to form setting; the packer rubber cylinder (4) forms a sealing cavity (14) with the central shaft (1), the testing casing pipe (5) and the concentric circle bottom plate (10) after setting, and a display agent (15) is placed in the sealing cavity (14); the test device is placed in a high-temperature autoclave (16) with a corrosive medium after being assembled.

Images