Integral piston cylinder composite material packer

Abstract

The utility model belongs to the technical field of oil and gas field exploitation equipment, and discloses an integral piston cylinder composite material packer which comprises an upper connector, a central pipe and a lower connector which are coaxially and sequentially connected, a connecting sleeve, a baffle ring, a piston cylinder outer barrel and a rubber barrel are coaxially and sequentially arranged on the outer wall of the central pipe from left to right, and the connecting sleeve is fixedly connected with the end of the central pipe. The baffle ring is fixed to the outer wall of the center pipe and abuts against one end of the piston cylinder outer barrel, the piston cylinder outer barrel is arranged on the outer wall of the center pipe and can slide in the axial direction of the center pipe, and a pressure bearing cavity is defined by the inner wall of the piston cylinder outer barrel and the outer wall of the center pipe; according to the scheme, the outer wall of the center pipe is directly used as the inner side wall of the pressure bearing cavity, the integrated closed pressure bearing cavity is defined by the outer wall of the center pipe and the outer barrel of the piston cylinder, and the structure that a cavity is defined by splicing multiple sections of cylinder bodies and multiple sections of body barrels in an existing multi-section type piston cylinder packer is replaced; according to the utility model, the problems of more sections and more connection and sealing interfaces of a piston cylinder packer are solved.

Description

Technical Field

[0001] This solution belongs to the technical field of oil and gas field development equipment, specifically involving an integral piston cylinder composite material packer. Background Technology

[0002] Packers are mainly used to seal off producing or working layers to prevent fluids and pressures from interfering with each other. They are adaptable to various layering techniques and are used in almost every production stage of exploration and development. In particular, in the field of oil and gas field stimulation, packer segmentation stimulation is one of the important technologies for the effective utilization of multiple layers and sections of low-permeability, tight oil and gas reservoirs.

[0003] Most existing packers are multi-stage piston cylinder packers. Multi-stage piston cylinder packers are a type of hydraulic setting tool widely used in oil and gas well completion and staged fracturing operations. Their typical structure is composed of multiple piston cylinder sections, multiple body cylinder sections, and end joints connected in series. Each piston cylinder section is connected in sequence by threads or joints. Multiple seals are installed inside. The multi-stage pistons are driven to move in sequence by pressure in the tubing. The axial load is transmitted to the rubber sleeve through multiple conical surfaces or pressure rings, causing the rubber sleeve to be axially compressed and radially expanded, thereby achieving annular sealing in the casing.

[0004] For example, the existing publication (announcement) number CN219176302U discloses a wedge-type self-dissolving k341 packer, which includes a central tube; the central tube is fixedly installed together with an upper connector and a lower connector respectively, a retaining ring is fixedly installed on the outside of the lower connector, and a pressure cap, a soluble glue cylinder, a cone and a piston cylinder are sequentially pressed and installed between the upper connector and the retaining ring. The cone is fixedly connected to the central tube by at least one shear pin. A sealing cavity is formed between the annular protrusion, the piston cylinder, the retaining ring and the central tube. At least one liquid inlet hole communicating with the sealing cavity is provided on the central tube, and a backstop lock ring is fixedly installed on the upper inner side of the piston cylinder.

[0005] The packer mentioned above is a multi-stage piston cylinder packer. Although it can adapt to higher setting pressure and multi-stage fracturing conditions, it is sensitive to machining and assembly precision due to the many cylinder segments, numerous connection and sealing interfaces, and long hydraulic transmission chain. After long-term service, it is prone to pressure loss, insufficient setting, or internal leakage failure due to factors such as loose threads, aging seals, and scaling blockage. Utility Model Content

[0006] The purpose of this solution is to provide an integral piston cylinder composite material packer to solve the problems of existing piston cylinder packers having multiple segments and numerous connection and sealing interfaces.

[0007] To achieve the above objectives, this solution provides an integral piston-cylinder composite material packer, comprising an upper connector, a central tube, and a lower connector coaxially connected in sequence. The outer wall of the central tube is coaxially provided with a connecting sleeve, a retaining ring, a piston cylinder outer cylinder, and a rubber sleeve from left to right. The connecting sleeve is fixedly connected to the end of the central tube. The retaining ring is fixed to the outer wall of the central tube and abuts against one end of the piston cylinder outer cylinder. The piston cylinder outer cylinder is located on the outer wall of the central tube and can slide axially along the central tube. The inner wall of the piston cylinder outer cylinder and the outer wall of the central tube enclose a pressure-bearing cavity. A pressure transmission channel is provided on the central tube, and the two ends of the pressure transmission channel communicate with the inner cavity of the central tube and the pressure-bearing cavity, respectively. A shear pin passes through the piston cylinder outer cylinder, and the free end of the shear pin is fixedly connected to the central tube. One end of the rubber sleeve abuts against the free end of the piston cylinder outer cylinder, and the free end of the rubber sleeve is fixedly connected to the outer wall of the central tube.

[0008] The principle and effect of this solution are as follows: By coaxially connecting the upper connector, central tube, and lower connector in sequence to form the overall load-bearing base of the packer, the outer wall of the central tube directly serves as the inner wall of the pressure-bearing cavity, forming an integrated closed pressure-bearing cavity with the outer cylinder of the piston cylinder. This replaces the existing multi-section piston cylinder packer structure that relies on multiple cylinder sections and multiple body sections to splice together to enclose the cavity. During the well run-in process, the shear pins axially lock the outer cylinder of the piston cylinder to the central tube, preventing premature mis-setting during well run-in. When pressure is applied to the inner cavity of the central tube through the tubing, the high-pressure working fluid enters the pressure-bearing cavity through the pressure transmission channel on the central tube, generating axial thrust on the outer cylinder of the piston cylinder. When the pressure rises to the preset value, the shear pins are sheared, releasing the lock on the outer cylinder of the piston cylinder. The outer cylinder of the piston cylinder slides axially along the central tube, continuously pushing the rubber sleeve that abuts against the free end of the outer cylinder of the piston cylinder, causing the rubber sleeve to be axially compressed and radially expanded, ultimately fitting against the inner wall of the casing to achieve the sealing of the casing annulus. This solution reduces the number of cylinder segments, redundant threaded connections, and matching sealing points by using an integral pressure-bearing chamber. This reduces the risk of internal leakage and pressure loss caused by loose threads and aging and wear of seals in existing multi-segment structures. It also shortens the hydraulic power transmission path and reduces the requirements for the packer's parts processing and on-site assembly precision.

[0009] Furthermore, the outer cylinder of the piston cylinder has a through radial shearing hole in its wall, and the outer wall of the central tube has a fixing hole coaxial with the radial shearing hole. The shear pin passes through the radial shearing hole, and the free end of the shear pin is fixed in the fixing hole.

[0010] The principle and effect of this scheme are as follows: the shear pin is passed through the radial shear hole and its free end is fixed in the fixed hole. During the well running process, the shear pin directly and rigidly locks the outer cylinder of the piston cylinder to the central tube. When the pressure in the central tube is increased to the set value, the hydraulic pressure in the pressure chamber pushes the outer cylinder of the piston cylinder to generate an axial force, so that the shear pin is sheared at the radial shear hole.

[0011] Furthermore, the shear pins are provided in multiple quantities, and the multiple shear pins are arranged at intervals along the circumference of the central tube.

[0012] The principle and effect of this scheme is to evenly distribute the axial locking load of the piston cylinder outer cylinder.

[0013] Furthermore, sealing rings are provided at both ends of the pressure-bearing cavity along its axial direction. One sealing ring is located between the retaining ring and one end of the central tube, and the other sealing ring is located between the sliding mating surfaces of the piston cylinder outer cylinder and the central tube.

[0014] The principle and effect of this solution is to form a double-sided seal on the pressure chamber, thereby preventing leakage of high-pressure working fluid.

[0015] Furthermore, the retaining ring is fixedly connected to the outer wall of the central tube by at least one screw.

[0016] The principle and effect of this solution is to form an axial limiting boundary for the pressure-bearing cavity.

[0017] Furthermore, the outer cylinder of the piston cylinder has a through guide groove on its wall, and the guide groove is arranged along the length direction of the outer cylinder of the piston rod. The outer wall of the central tube has a locking hole that matches the guide groove. The screw passes through the guide groove, and the free end of the screw is fixed in the locking hole.

[0018] The principle and effect of this solution are as follows: the guide groove is used to restrict the circumferential rotation of the piston cylinder outer cylinder.

[0019] Furthermore, the pressure transmission channel is a radially arranged pressure transmission channel, and there are multiple pressure transmission channels, which are distributed at intervals along the circumference of the central tube.

[0020] The principle and effect of this scheme is to allow the high-pressure working fluid in the inner cavity of the central tube to enter the pressure-bearing cavity quickly and evenly.

[0021] Furthermore, a one-way valve is provided in the pressure transmission channel, which is used to allow the working fluid in the central tube to flow unidirectionally into the pressure-bearing chamber.

[0022] The principle and effect of this solution are as follows: During the setting of the pressure chamber, the high-pressure working fluid in the central tube needs to enter the pressure chamber through the pressure transmission channel to push the outer cylinder of the piston cylinder to slide and compress the rubber sleeve. If the pressure transmission channel is a straight-through structure, the high-pressure working fluid in the pressure chamber will flow back to the central tube after setting. Furthermore, pressure fluctuations in the working fluid within the pressure chamber or central tube can cause pressure loss in the pressure chamber, retraction of the outer cylinder of the piston cylinder, and ultimately, the rubber sleeve rebounding and losing its seal. Therefore, a one-way valve needs to be installed in the pressure transmission channel to solve this problem. The one-way valve in this solution only allows the working fluid in the central tube to flow unidirectionally into the pressure chamber. During the setting stage, it does not obstruct the high-pressure working fluid from entering the pressure chamber to build pressure and blocks the reverse flow path of the working fluid in the pressure chamber. This ensures that the outer cylinder of the piston cylinder stably pushes the rubber sleeve without retraction and also prevents impurities in the wellbore from flowing back into the pressure chamber, thus avoiding jamming of the outer cylinder of the piston cylinder.

[0023] Furthermore, the one-way valve includes a sealing ball and a spring. The sealing ball is disposed in the pressure transmission channel, one end of the spring is fixedly connected to the sealing ball, and the free end is fixedly connected to the pressure transmission channel.

[0024] The principle and effect of this scheme are as follows: relying on the preload of the spring to push the sealing ball to block the pressure transmission channel, when the working fluid pressure in the central tube is greater than the spring preload, the sealing ball is pushed open by the high-pressure working fluid, the spring is compressed, the pressure transmission channel is opened, the working fluid flows into the pressure chamber in one direction, and the backflow of the working fluid in the pressure chamber is restricted.

[0025] Furthermore, the inlet end of the pressure transmission channel is smaller than the outlet end; the diameter of the sealing ball is larger than the inlet diameter and smaller than the outlet diameter.

[0026] The principle and effect of this solution are as follows: the pressure transmission channel adopts a stepped structure with the inlet end smaller than the outlet end, and the diameter of the sealing ball is larger than the inlet port diameter and smaller than the outlet port diameter, so that the sealing ball can better seal the pressure transmission channel. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the integral piston cylinder composite material packer of this utility model;

[0028] Figure 2 This is a schematic diagram of the internal structure of the pressure transmission channel and pressure bearing cavity of this utility model.

[0029] The corresponding labels in the attached diagram are named as follows: connecting sleeve 1, screw 2, retaining ring 3, central tube 4, shear pin 5, piston cylinder outer cylinder 6, pressure bearing chamber 7, lower connector 8, radial shear hole 9, sealing ring 10, guide groove 11, pressure transmission channel 12, sealing ball 13, and spring 14. Detailed Implementation

[0030] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0031] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0032] Furthermore, features specified as "first" or "second" may explicitly or implicitly include one or more of those features, used to distinguish and describe features, without any order or emphasis. In the description of this utility model, unless otherwise stated, "multiple" means two or more.

[0033] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0034] The following is in conjunction with the appendix Figure 1 and 2This utility model describes an integral piston cylinder composite material packer, specifically comprising an upper connector (not shown), a central tube 4, and a lower connector 8, which are coaxially and fixedly connected from left to right, forming the main load-bearing base of the packer. The central tube 4 is made of free-cutting composite material and serves as the inner load-bearing base of the integral piston cylinder. From left to right, the outer wall of the central tube 4 is coaxially fitted with a connecting sleeve 1, a retaining ring 3, a piston cylinder outer cylinder 6, and a rubber sleeve (not shown). The connecting sleeve 1 is fixedly connected to the left end of the central tube 4, and the inner cavity of the connecting sleeve 1 is coaxially connected to the inner cavity of the central tube 4 to form a through flow channel, providing a passage for the transmission of hydraulic fluid and bearing the tensile and compressive loads transmitted by the upper tubing. The retaining ring 3 is rigidly fixed to the outer wall of the central tube 4 by at least one screw 2. The left end face of the retaining ring 3 forms an axial limiting contact with the right end face of the connecting sleeve 1, providing a stable left axial boundary for the pressure-bearing cavity 7. The piston cylinder outer cylinder 6 is coaxially sleeved on the outer wall of the central tube 4 and can slide freely along the axial direction of the central tube 4.

[0035] Please continue reading Figure 1 The inner wall of the piston cylinder outer cylinder 6 and the outer wall of the central tube 4 directly enclose each other to form an integral closed pressure-bearing cavity 7. This integral cavity structure replaces the multi-section cylinder body and multi-section body cylinder splicing form of the traditional multi-section piston cylinder. Both ends of the pressure-bearing cavity 7 are equipped with sealing rings 10. One sealing ring 10 is set between the mating surface of the retaining ring 3 and the central tube 4, and the other sealing ring 10 is set between the sliding mating surface of the piston cylinder outer cylinder 6 and the central tube 4. The two sealing rings 10 form a double sealing protection to ensure that the high-pressure working fluid in the pressure-bearing cavity 7 does not leak, so that the hydraulic thrust can be stably transmitted to the piston cylinder outer cylinder 6. The outer cylinder 6 of the piston cylinder has a through radial shearing hole 9. The outer wall of the central tube 4 has a fixing hole (not shown) that is coaxial with the radial shearing hole 9. The shear pin 5 passes through the radial shearing hole 9 and the free end of the shear pin 5 is fixedly installed in the fixing hole. Multiple shear pins 5 are provided and are evenly distributed along the circumference of the central tube 4. This can evenly distribute the axial locking load of the outer cylinder 6 of the piston cylinder to improve the locking stability during the well-running stage.

[0036] Please continue reading Figure 1 The outer cylinder 6 of the piston cylinder also has a guide groove 11 extending along its length. The screw 2 passes through the guide groove 11 and its free end is fixed in the locking hole on the outer wall of the central tube 4. The guide groove 11 and the screw 2 cooperate to restrict the circumferential rotation of the outer cylinder 6 of the piston cylinder, without hindering its axial sliding, thus avoiding the rotation of the outer cylinder 6 of the piston cylinder causing the shear pin 5 hole to be misaligned and the force uneven. Multiple radially arranged pressure transmission channels 12 are opened on the central tube 4. The multiple pressure transmission channels 12 are evenly distributed along the circumference of the central tube 4. The two ends of the pressure transmission channels 12 are respectively connected to the inner cavity of the central tube 4 and the pressure bearing cavity 7, which can allow the high-pressure working medium in the inner cavity of the central tube 4 to enter the pressure bearing cavity 7 quickly and evenly, thereby improving the sealing pressure building efficiency.

[0037] Please continue reading Figure 2 The pressure transmission channel 12 is equipped with a one-way valve, which only allows the working fluid in the central tube 4 to flow into the pressure chamber 7 in one direction. In this embodiment, the one-way valve consists of a sealing ball 13 and a spring 14. The sealing ball 13 is located inside the pressure transmission channel 12, and one end of the spring 14 is fixedly connected to the sealing ball 13. The free end of the spring 14 is fixedly connected to the inner wall of the pressure transmission channel 12. The inlet port diameter of the pressure transmission channel 12 is smaller than the outlet port diameter, and the diameter of the sealing ball 13 is larger than the inlet port diameter and smaller than the outlet port diameter. Under normal conditions, the preload of the spring 14 pushes the sealing ball 13 to tightly seal the inlet end of the pressure transmission channel 12. When setting, the high-pressure working fluid in the central tube 4 pushes open the sealing ball 13 to open the channel. After setting, the sealing ball 13 quickly resets and seals, blocking the reverse flow path of the working fluid in the pressure chamber 7, and continuously maintaining the high-pressure state inside the pressure chamber 7. At the same time, it can prevent impurities and scale in the wellbore from flowing back into the pressure chamber 7 and avoid jamming of the piston cylinder outer cylinder 6.

[0038] Please continue reading Figure 1 The rubber sleeve is coaxially sleeved on the outer wall of the central tube 4. One end of the rubber sleeve abuts against the free end of the outer cylinder 6 of the piston cylinder. The free end of the rubber sleeve is fixedly connected to the rigid limiting part (not shown) on the outer wall of the central tube 4. When the outer cylinder 6 of the piston cylinder slides axially, it can directly push the rubber sleeve, so that the rubber sleeve is axially compressed and generates radial expansion, and finally fits tightly with the inner wall of the sleeve to achieve the sealing of the sleeve annulus.

[0039] The packer in this embodiment is used as follows: During the packer's operation phase when it is lowered into the wellbore, it is in an unset state. The shear pins 5 rigidly lock the piston cylinder outer cylinder 6 and the central tube 4 axially. The screws 2 and the guide grooves 11 restrict the circumferential rotation of the piston cylinder outer cylinder 6. The double locking structure prevents premature setting during the packer's lowering process. The integrated piston cylinder structure is compact and improves the stability of the lowering process. After the packer is lowered to the predetermined well depth, it enters the hydraulic setting stage. Hydraulic pressure is applied to the inner cavity of the central tube 4 through the tubing. The high-pressure working fluid opens the check valve through multiple circumferentially distributed pressure transmission channels 12 and enters the pressure chamber 7. As the pressure continues to rise, the hydraulic thrust in the pressure chamber 7 acts on the piston cylinder outer cylinder 6. When the pressure reaches the design shear value of the shear pins 5, multiple shear pins 5 are simultaneously sheared, releasing the axial lock of the piston cylinder outer cylinder 6. Under the action of hydraulic thrust, the piston cylinder outer cylinder 6 slides axially along the central tube 4, continuously pushing the rubber sleeve to compress it axially and expand it radially, completing the casing annulus packing. During the pressure holding stage after the packer is set, the one-way valve resets and seals the pressure transmission channel 12, forming a closed high-pressure cavity in the pressure-bearing chamber 7. This allows for stable internal pressure without continuous surface pressurization. The piston cylinder outer cylinder 6 continuously pushes the rubber sleeve, and the sealing ring 10 continuously ensures the sealing of the pressure-bearing chamber 7. In the unsealing stage after the operation, the packer is drilled out entirely using drilling tools. The easily machinable composite material used in the central tube 4 and piston cylinder outer cylinder 6 can be efficiently broken into fine debris, which is then drilled out along with components such as the connecting sleeve 1, retaining ring 3, screw 2, and shear pin 5. The debris is carried out of the wellbore by the circulating fluid, eliminating the need for lifting the tubing string or mechanical unsealing. This simplifies the unsealing process, reduces the risk of jamming and unsealing failure due to long-term service, and allows for rapid restoration of wellbore access.

[0040] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. An integral piston cylinder composite material packer, comprising an upper connector, a central tube, and a lower connector coaxially and sequentially connected, characterized in that: The outer wall of the central tube is coaxially arranged from left to right with a connecting sleeve, a retaining ring, a piston cylinder outer cylinder, and a rubber sleeve. The connecting sleeve is fixedly connected to the end of the central tube. The retaining ring is fixed to the outer wall of the central tube and abuts against one end of the piston cylinder outer cylinder. The piston cylinder outer cylinder is located on the outer wall of the central tube and can slide along the axial direction of the central tube. The inner wall of the piston cylinder outer cylinder and the outer wall of the central tube enclose a pressure-bearing cavity. A pressure transmission channel is opened on the central tube, and the two ends of the pressure transmission channel are respectively connected to the inner cavity of the central tube and the pressure-bearing cavity. A shear pin is inserted through the piston cylinder outer cylinder, and the free end of the shear pin is fixedly connected to the central tube. One end of the rubber sleeve abuts against the free end of the piston cylinder outer cylinder, and the free end of the rubber sleeve is fixedly connected to the outer wall of the central tube.

2. The integral piston cylinder composite material packer according to claim 1, characterized in that: The outer cylinder of the piston cylinder has a through radial shearing hole in its wall, and the outer wall of the central tube has a fixing hole coaxial with the radial shearing hole. The shear pin passes through the radial shearing hole, and the free end of the shear pin is fixed in the fixing hole.

3. The integral piston cylinder composite material packer according to claim 1, characterized in that: The shear pins are provided in multiples, and the multiple shear pins are spaced apart along the circumference of the central tube.

4. The integral piston cylinder composite material packer according to claim 1, characterized in that: Both ends of the pressure-bearing cavity are provided with sealing rings. One sealing ring is located between the retaining ring and one end of the central tube, and the other sealing ring is located between the sliding mating surface of the piston cylinder outer cylinder and the central tube.

5. The integral piston cylinder composite material packer according to claim 1, characterized in that: The retaining ring is fixedly connected to the outer wall of the central tube by at least one screw.

6. The integral piston cylinder composite material packer according to claim 5, characterized in that: The outer cylinder of the piston cylinder has a through guide groove on its wall, and the guide groove is arranged along the length of the outer cylinder of the piston rod. The outer wall of the central tube has a locking hole that matches the guide groove. The screw passes through the guide groove, and the free end of the screw is fixed in the locking hole.

7. The integral piston cylinder composite material packer according to claim 1, characterized in that: The pressure transmission channel is a radially arranged pressure transmission channel, and there are multiple pressure transmission channels, which are distributed at intervals along the circumference of the central tube.

8. The integral piston cylinder composite material packer according to claim 1, characterized in that: The pressure transmission channel is equipped with a one-way valve, which is used to allow the working fluid in the central tube to flow into the pressure chamber in one direction.

9. The integral piston cylinder composite material packer according to claim 8, characterized in that: The one-way valve includes a sealing ball and a spring. The sealing ball is disposed in the pressure transmission channel. One end of the spring is fixedly connected to the sealing ball, and the free end is fixedly connected to the pressure transmission channel.

10. The integral piston cylinder composite material packer according to claim 9, characterized in that: The inlet end of the pressure transmission channel is smaller than the outlet end; the diameter of the sealing ball is larger than the inlet diameter and smaller than the outlet diameter.

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