A compression packer rubber cartridge performance testing device

Abstract

The present invention discloses a device for testing the performance of a compression-type packer rubber cartridge, comprising a rubber cartridge testing unit and a rubber cartridge retraction amount setting mechanism for setting the retraction amount of the rubber cartridge. The device for testing the performance of a compression-type packer rubber cartridge of the present invention is provided with a packer rubber cartridge retraction amount setting mechanism, which allows the retraction amount of the packer rubber cartridge to be pre-set as needed. Because the retraction amount can be arbitrarily adjusted, the pressure bearing capacity and compression amount of the rubber cartridge can be measured based on this, providing a scientific basis for the design of the packer rubber cartridge and locking mechanism.

Description

Technical Field

[0001] The present invention relates to the field of sand control and completion of oil and natural gas wells, and in particular to a performance detection device for a compression packer rubber cylinder. Background Art

[0002] Packers are widely used in oil and gas field drilling, completion, sand control, production, and workover, and are essential equipment in oil production. Conventional packers are classified into two types: compression and expansion. The rubber cylinder is the core component of the packer, and the sealing performance of the packer's rubber sleeve is crucial to its success. The sealing performance of the rubber sleeve is affected by many factors, including the chemical composition of the rubber sleeve material, the geometry of the rubber sleeve and its shoulder, the setting load, the ambient temperature, and the properties of the fluid.

[0003] Another important factor affecting the sealing performance of the rubber sleeve is the amount of retraction of the packer's locking mechanism. When the packer's setting force reaches the set value and the setting load is removed, the packer's locking mechanism will retract to a certain extent, causing the rubber sleeve to elongate accordingly. This reduces the contact stress between the rubber sleeve and the inner wall of the casing, reducing the sealing performance of the rubber sleeve. This retraction is characterized by the rubber sleeve being compressed first and then extended to a certain length. This is very different from directly compressing the rubber sleeve to this length. The latter directly compresses the rubber sleeve to a certain amount, while the former compresses the rubber sleeve first and then extends to achieve the desired compression.

[0004] Current research on packer cartridge testing devices focuses on the impact of factors such as setting load, temperature, and compression (sleeve travel) on cartridge performance, with little attention paid to the impact of backoff on performance. While some testing devices incorporate locking mechanisms, the backoff is fixed and non-adjustable, with different locking mechanisms offering varying backoff amounts. Practical research requires studying and measuring the impact of varying backoff on cartridge sealing performance, thereby enabling the design of improved locking mechanisms and packers.

[0005] A Chinese patent with authorization announcement number CN103293062B discloses a test and detection tool for compression-type packer rubber cartridges. The tool can detect multiple types of rubber cartridges, improve tool utilization, save production costs, and has the advantages of simple, reliable, and accurate detection. It has a fixed locking mechanism, but the retraction amount cannot be adjusted.

[0006] The Chinese patent with authorization announcement number CN108414199B discloses a visual performance testing device for the rubber sleeve of the packer, which can realize the precise measurement operation of the displacement of the rubber sleeve. Specifically, it can accurately measure the seating distance of the rubber sleeve during the pressure injection process and the retraction distance of the rubber sleeve after the pressure is released; it can realize fatigue testing of the rubber sleeve and has a fixed locking mechanism, but the retraction amount cannot be adjusted. Summary of the Invention

[0007] The purpose of the present invention is to provide a compression type packer rubber performance detection device which has a novel and unique structure, is easy to use, and can set the packer rubber sleeve retraction amount; the specific technical solution is as follows:

[0008] A device for detecting performance of a compression packer rubber cartridge comprises a rubber cartridge testing unit and a rubber cartridge retraction amount setting mechanism for setting the retraction amount of the rubber cartridge.

[0009] Furthermore, the rubber cartridge test unit is composed of a center tube, a test sleeve, a piston and a sealing plug; the test sleeve is arranged outside the center tube, the front end of the center tube is sealedly connected to the front end of the test sleeve, and the sealing plug is connected to the rear end of the test sleeve to form a piston cavity of the piston; a rubber cartridge test cavity is provided between the inner wall of the test sleeve and the outer wall of the center tube.

[0010] Furthermore, the rubber cylinder retraction amount setting mechanism is an adjustable piston limiting mechanism that limits the piston retraction distance.

[0011] Furthermore, the piston limiting mechanism is a limiting body, and the limiting body is connected to the tail end of the sealing plug through a thread; the limiting body is provided with a limiting portion that prevents the piston rod of the piston from retreating.

[0012] Furthermore, the limiting body is an annular body provided with an internal thread adapted to the external thread of the sealing plug, and the end of the inner wall of the annular body is provided with the limiting portion, which is a ring platform or a protrusion with an inner diameter smaller than the diameter of the piston rod.

[0013] The compression type packer rubber cylinder performance detection device of the present invention is provided with a packer rubber cylinder retraction amount setting mechanism, through which the retraction amount of the packer rubber cylinder can be pre-set as needed; since the retraction amount can be adjusted arbitrarily, the pressure bearing capacity and compression amount of the rubber cylinder can be measured on this basis, providing a scientific basis for the design of the packer rubber cylinder and the locking mechanism, so as to improve the performance and reliability of the packer. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the compression packer rubber cartridge performance detection device of the present invention.

[0015] In the figure: 1. Test sleeve; 2. Center tube; 3. Pressure ring; 4. Piston; 5. Sealing plug; 6. Pressure cap; 7. Sealing ring; 8. Sealing ring; 9. Sealing ring; 10. Sealing ring; 11. Mounting sleeve; 12. Rubber cylinder assembly; 12-1. Shoulder guard; 12-2. Outer rubber cylinder; 12-3. Inner rubber cylinder; 12-4. Outer rubber cylinder; 12-5. Shoulder guard; 13. Sealing ring; 13. Sealing ring; A. Front pressure test hole; B. Rear pressure test hole; C. Pressure hole; D. End face; E. Water hole; F. Inclined surface; G. End face; L. Reference value of retraction amount. DETAILED DESCRIPTION

[0016] The present invention is described in more detail below using the following examples. The present invention can be embodied in many different forms and should not be construed as being limited to the exemplary embodiments described herein.

[0017] For ease of description, spatially relative terms such as "upper," "lower," "left," and "right" may be used herein to describe the relationship of one element or feature shown in the figures relative to another element or feature. It should be understood that the spatial terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown in the figures. For example, if the device in the figures is inverted, an element described as being "below" another element or feature would be positioned "above" the other element or feature. Thus, the exemplary term "below" can encompass both above and below orientations. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein should be interpreted accordingly.

[0018] The compression packer rubber cartridge performance testing device in this embodiment includes a rubber cartridge testing unit; the rubber cartridge testing unit can employ various conventional solutions. To facilitate studying the performance of the rubber cartridge under different retraction conditions, this embodiment also incorporates a rubber cartridge retraction setting mechanism. This mechanism causes the rubber cartridge to retract to a predetermined size after pressure relief. This retraction setting mechanism can be implemented using a limiter mechanism that directly blocks the retraction range of the rubber cartridge, or by preventing the compression mechanism from retracting, limiting the retraction of the rubber cartridge to a predetermined size.

[0019] The embodiment may adopt Figure 1 The structure shown in the figure is as follows; the cartridge test unit mainly consists of a central tube 2, a test sleeve 1, a piston 4, and a sealing plug 5. A cartridge test cavity is provided between the inner wall of the test sleeve and the outer wall of the central tube to accommodate the tested cartridge or cartridge assembly 12 and provide space for the piston 4 to move.

[0020] The test sleeve 1 is sleeved outside the center tube 2, and a limiting step is provided at the front end of the inner hole of the test sleeve 1 to prevent the center tube 2 from passing through the front side; the outer diameter of the front end of the center tube 2 is larger than the inner diameter of the limiting step.

[0021] From front to back, the center tube 2 is provided with coaxial cylindrical first, second, and third working surfaces. The first working surface is provided with a sealing groove, which is sealed to the interior of the test sleeve 1 via a sealing ring 13 within the sealing groove. The second working surface, with a smaller diameter than the first, is used to mount the rubber cartridge or rubber cartridge assembly 12 to be tested. The rubber cartridge assembly 12 comprises, from front to back, the shoulder guard 12-5, the outer rubber cartridge 12-4, the inner rubber cartridge 12-3, the outer rubber cartridge 12-2, and the shoulder guard 12-1.

[0022] The piston rod of the piston 4 is tubular and lighter than a solid piston rod.

[0023] The third working surface cooperates with the inner wall of the piston rod, and the diameter of the third working surface is smaller than that of the second working surface, forming a step.

[0024] A chamfer F is provided at one end where the second working surface and the third working surface are connected, so as to avoid scratching the rubber cartridge assembly 12 during installation and facilitate smooth installation.

[0025] To ensure compatibility with the operating environment, a pressure ring 3 is provided to secure the rubber cartridge assembly 12 in place. The length of the second working surface should be greater than the length of the rubber cartridge assembly 12, with sufficient margin. The length of the mounting sleeve 11, i.e., the maximum movable distance of the pressure ring 3, must be greater than the maximum compressible distance of the rubber cartridge assembly to ensure that the rubber cartridge assembly can be fully compressed.

[0026] The bottom of the central tube 2 is provided with a stepped surface; the central tube 2 can be easily separated from the test sleeve 1 by means of the end surface D of the stepped surface.

[0027] In order to facilitate the installation of the rubber cartridge assembly 12 , a mounting sleeve 11 is further provided. The inner wall of the mounting sleeve is clearance-matched with the third working surface; and the outer wall of the mounting sleeve is clearance-matched with the inner wall of the rubber cartridge assembly 12 .

[0028] A water hole E is provided between the inner wall and the outer wall of the pressure ring 3 , and when the piston 4 pushes the pressure ring 3 to squeeze the rubber cylinder assembly 12 , the liquid between the inner wall and the third working surface is discharged in time.

[0029] The test sleeve 1 is provided with a front pressure test hole A and a rear pressure test hole B; the front pressure test hole A is connected to the front end of the rubber cartridge test cavity; the position of the rear pressure test hole B should exceed the rear end of the rubber cartridge assembly 12; the front pressure test hole A and the rear pressure test hole B are used to test the sealing effect of the rubber cartridge assembly 12 under pressure.

[0030] The sealing plug 5 is fixedly connected to the rear end of the test sleeve 1 by a thread, and the connection is sealed by a sealing ring 8. The sealing plug 5, the test sleeve 1 and the center tube 2 form the piston chamber of the piston 4. Among them, the driving chamber is between the rear end face of the piston 4 and the sealing plug 5. The sealing plug 5 is provided with a pressure hole C connected to the driving chamber, and the piston 4 is driven forward by pressure. The sealing plug 5 and the outer wall of the piston rod are sealed and slidably connected by a sealing ring 7. The outer edge of the piston 4 is sealed and slidably connected to the inner wall of the test sleeve 1 by a sealing ring 9; the inner edge of the piston 4 is sealed and slidably connected to the third working surface by a sealing ring 10.

[0031] The stopper is an annular pressure cap 6 with internal threads that mate with the external threads of the sealing plug 5. The pressure cap 6 is threadedly connected to the rear end of the sealing plug 5. The pressure cap 6 has an annular stopper to prevent the piston rod of the piston 4 from retracting. A bump can also be used to prevent the piston rod of the piston 4 from retracting. Using an external connection is more convenient.

[0032] An internal connection method can also be adopted, in which a plug is matched with the internal thread at the tail end of the sealing plug 5 to prevent the piston rod of the piston 4 from retreating.

[0033] Other forms of piston limit mechanisms with adjustable set distances can also be used as the rubber cylinder retraction amount setting mechanism. A pin and a pin hole can also be used to limit the retraction distance of the piston rod of the piston 4; no further details will be given here.

[0034] To facilitate testing the performance testing device for the compression packer rubber cartridge of this embodiment, first install the installation sleeve 11 on the center pipe 2 equipped with the sealing ring 13, so that the rubber cartridge assembly 12 can be installed sequentially from the rear end. Then, remove the installation sleeve 11, install the pressure ring 3 on the center pipe 2, and install the center pipe 2 together with the rubber cartridge assembly 12 and the pressure ring 3 into the test sleeve 1. Next, install the sealing rings 9 and 10 on the piston 4, and then install the piston 4 into the annular space between the center pipe 2 and the test sleeve 1. Install the sealing rings 7 and 8 on the sealing plug 5, and install the sealing plug 5 on the test sleeve 1 through threads. Finally, install the pressure cap 6 on the sealing plug 5 until the rear end face of the piston 4 rests on the end face G of the inner hole of the pressure cap 6. A reference surface can be set on the sealing plug 5. At this time, the distance between the front end face of the pressure cap 6 and the reference surface is the retraction reference value L.

[0035] Before setting, the initial retraction dimension L0 is recorded. During setting, the pressure is applied to the predetermined setting pressure through the pressure hole C. The piston 4 moves forward, compressing the rubber sleeve assembly 12 via the pressure ring 3. The rear end of the piston 4 separates from the end face G of the inner bore of the pressure cap 6. At this time, the pressure cap 6 is rotated clockwise, causing the rear end face of the piston 4 to rest against the end face G of the inner bore of the pressure cap 6 again. The initial retraction dimension L0 is reduced to the fully compressed dimension L1; the retraction amount of the rubber sleeve assembly is now zero. The pressure cap 6 can now be rotated counterclockwise to adjust the set retraction amount of the rubber sleeve assembly. The adjustment method is to rotate the pressure cap 6 counterclockwise moderately and then release the pressure. Under the action of the rubber sleeve assembly's rebound force, the rear end face of the piston 4 always rests against the end face G of the inner bore of the pressure cap 6, causing the fully compressed dimension L1 to increase to the set retraction dimension L2. The difference between the set retraction dimension L2 and the fully compressed dimension L1 is the retraction amount of the rubber sleeve assembly. The difference between L0 and L2 is the actual compression amount of the rubber sleeve assembly.

[0036] At this point, the rubber cartridge assembly remains compressed, and the annular space formed by the second working surface of the center tube 2 and the cylindrical surface with the maximum inner diameter of the test sleeve is separated by the rubber cartridge assembly 12. Keeping hole A open and applying pressure to hole B can measure the rubber cartridge assembly's ability to withstand a downward pressure differential under the specified retraction amount. Keeping hole B open and applying pressure to hole A can measure the rubber cartridge assembly's ability to withstand an upward pressure differential under the specified retraction amount. Adjusting the set retraction amount and retesting can determine the rubber cartridge assembly's ability to withstand upward and downward pressure differentials under different set retraction amounts. Release the pressure after the test is complete.

[0037] When disassembling the device, first apply pressure to hole C to reduce the tightening force of the piston 4 on the pressure cap 6 caused by the rebound force of the rubber cylinder assembly, remove the pressure cap 6, and release the pressure; then remove the sealing plug 5, take out the piston 4, and finally use a stick of appropriate diameter to push the end face D from the inner hole of the front end of the center tube 2 to withdraw the center tube 2, the rubber cylinder assembly 12 and the pressure ring 3 from the test sleeve 1.

[0038] The beneficial effect of the present invention is that the ability of the rubber cartridge assembly to withstand the upper and lower pressure differences under different retraction amounts can be measured, and the compression amount of the rubber cartridge assembly can be measured at the same time, providing a scientific basis for designing the rubber cartridge assembly and the packer.

[0039] The above examples are only used to illustrate the present invention. In addition, there are many different implementation methods. These implementation methods are all conceivable by those skilled in the art after understanding the concept of the present invention. Therefore, they are not listed here one by one.

Claims

1. A compression packer rubber cartridge performance testing device, comprising a rubber cartridge testing unit, characterized in that: It also includes a rubber cylinder retraction amount setting mechanism for setting the retraction amount of the rubber cylinder; The rubber cartridge test unit includes a center tube, a test sleeve, a piston, and a sealing plug; the test sleeve is sleeved outside the center tube, the front end of the center tube is sealedly connected to the front end of the test sleeve, and the sealing plug is connected to the rear end of the test sleeve to form a piston cavity of the piston; a rubber cartridge test cavity is provided between the inner wall of the test sleeve and the outer wall of the center tube to accommodate the rubber cartridge assembly to be tested; a limiting step is provided at the front end of the inner hole of the test sleeve to prevent the center tube from passing through the front side; The rubber cylinder retraction amount setting mechanism is an adjustable piston limiting mechanism that limits the piston retraction distance; The test sleeve is provided with a front pressure test hole A and a rear pressure test hole B; the front pressure test hole A is connected to the front end of the rubber cylinder test cavity; the rear pressure test hole B is located beyond the rear end of the rubber cylinder assembly; the front pressure test hole A and the rear pressure test hole B are used to test the sealing effect of the rubber cylinder assembly under pressure; the driving cavity is between the rear end surface of the piston and the sealing plug, and the sealing plug is provided with a pressure hole C connected to the driving cavity, The piston limiting mechanism is a limiting body, which is connected to the tail end of the sealing plug through a thread; the limiting body is provided with a limiting portion to prevent the piston rod of the piston from retreating, and the limiting body is an annular body pressure cap provided with an internal thread adapted to the external thread of the sealing plug, Before setting, the initial retraction size L0 is recorded. When setting, the pressure is applied to the predetermined setting pressure through the pressure hole C, the piston moves forward, and the rubber cylinder assembly is compressed by the pressure ring. The rear end of the piston is separated from the end face G of the inner hole of the pressure cap. At this time, the pressure cap is rotated clockwise so that the rear end face of the piston rests on the end face G of the inner hole of the pressure cap again, and the initial retraction size L0 is reduced to the fully compressed size L1; at this time, the retraction amount of the rubber cylinder assembly is 0; at this time, the pressure cap is rotated counterclockwise to adjust the set retraction amount of the rubber cylinder assembly; the adjustment method is to rotate the pressure cap counterclockwise appropriately, and then release the pressure. Under the action of the rebound force of the rubber cylinder assembly, the rear end face of the piston always rests on the end face G of the inner hole of the pressure cap, so that the fully compressed size L1 is increased to the set retraction size L2. The difference between the set retraction size L2 and the fully compressed size L1 is the retraction amount of the rubber cylinder assembly, and the difference between L0 and L2 is the actual compression amount of the rubber cylinder assembly; At this time, the rubber cartridge assembly is still in a compressed state, and the annular space formed by the center tube and the maximum inner diameter cylindrical surface of the test sleeve is separated by the rubber cartridge assembly; keep hole A open, apply pressure to hole B, and measure the ability of the rubber cartridge assembly to withstand the downward pressure difference under the above-mentioned retraction amount; keep hole B open, apply pressure to hole A, and measure the ability of the rubber cartridge assembly to withstand the upward pressure difference under the above-mentioned retraction amount; adjust the set retraction amount and retest to obtain the ability of the rubber cartridge assembly to withstand the upper and lower pressure differences under different set retraction amounts.

2. The compression packer rubber cartridge performance detection device according to claim 1, characterized in that: The end of the inner wall of the annular body pressure cap is provided with the limiting portion, which is a ring platform or a convex block with an inner diameter smaller than the diameter of the piston rod.

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