Large-drift-diameter composite metal pipe outer packer for horizontal well shaft reconstruction

Abstract

The invention provides a large-drift-diameter composite metal pipe outer packer for horizontal well shaft reconstruction, and relates to the technical field of petroleum downhole tools, the large-drift-diameter composite metal pipe outer packer comprises a pipe column body, a composite metal rubber sleeve, a hydraulic expansion control device and a valve system, and the composite metal rubber sleeve is arranged on the outer side of the pipe column body in a sleeving mode; the hydraulic expansion control device is connected to the interior of the pipe column body, the hydraulic expansion control device and the composite metal rubber sleeve are in telecommunication connection and are oppositely arranged, and the hydraulic expansion control device is used for controlling hydraulic pressure to enable the composite metal rubber sleeve to expand; the valve system is connected to the interior of the tubular column body and used for locking expansion liquid and maintaining constant expansion pressure. According to the valve system, during fracturing or acidification, the packing capacity of all well sections of the annulus can be guaranteed, fracturing construction operation can be conducted for multiple times, meanwhile, construction steps are simplified, and the problems that in the prior art, a packer is short in service life and small in application range are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of petroleum downhole tools, in particular to a large-diameter composite metal pipe external packer for horizontal wellbore reconstruction. Background Art

[0002] In recent years, unconventional oil and gas resources have faced poor reservoir conditions and are difficult to develop. Their effective development has mostly relied on horizontal wells + volume fracturing technology. However, the production decline of unconventional oil and gas wells is large and rapid. How to increase the production of unconventional oil and gas wells has become a major problem restricting the sustainable economic development of unconventional oil and gas reservoirs. Repeated fracturing technology is one of the effective means to increase the production and recovery rate of unconventional oil and gas wells. It can play many roles, such as increasing formation energy, creating new fractures or expanding old fractures, restoring fracture conductivity, and improving the degree of reserve utilization. In the early days of North America's shift to repeated fracturing, two technologies were mainly used: chemical temporary plugging and casing-in-solid casing. Chemical temporary plugging technology has low sealing pressure on the original perforations, making it difficult to control the flow direction of the fracturing fluid. After the casing-in-solid casing construction, the internal diameter is greatly reduced, limiting the construction pressure and displacement of repeated fracturing.

[0003] Packers are key downhole tools in oil and gas field development, primarily used for stratified acidizing, stratified fracturing, stratified water injection, stratified gas recovery, and stratified testing. However, conventional rubber packers are susceptible to high temperatures, high pressures, or corrosive fluids, leading to seal failure. Conventional metal packers lack elasticity and have difficulty adapting to irregular wellbore surfaces, resulting in a short service life and severely limited applicability. Summary of the Invention

[0004] The object of the present invention is to provide a large-diameter composite metal pipe external packer for horizontal wellbore reconstruction, which solves the problems of short service life and small application range of the packers in the prior art.

[0005] The technical solution of the present invention:

[0006] The present invention provides a large-diameter composite metal pipe external packer for horizontal wellbore reconstruction, comprising:

[0007] Pipe string body;

[0008] A composite metal rubber cylinder, the composite metal rubber cylinder being sleeved on the outside of the pipe body;

[0009] A hydraulic expansion control device, the hydraulic expansion control device being connected to the interior of the tubing body, the hydraulic expansion control device being electrically connected to and opposite to the composite metal rubber tube, and the hydraulic expansion control device being used to control the hydraulic pressure to expand the composite metal rubber tube;

[0010] A valve system is connected to the interior of the tubular body and is used to lock the expansion liquid and maintain a constant expansion pressure.

[0011] Furthermore, the two valve systems are respectively located on both sides of the hydraulic expansion starting device.

[0012] Furthermore, both ends of the pipe column body have threaded sections.

[0013] Furthermore, the composite metal rubber cylinder includes a rubber cylinder body and a plurality of metal rings evenly spaced and connected to the outer circle of the rubber cylinder.

[0014] Furthermore, the hydraulic expansion control device comprises at least a hydraulic pump, a hydraulic pipeline, an expansion chamber and a pressure sensor, and the shape of the expansion chamber matches the rubber cylinder.

[0015] Furthermore, the valve system at least includes a one-way valve, a pressure regulating valve and a pressure relief valve connected to a rubber cylinder, the one-way valve is connected between the hydraulic pipeline and the expansion chamber, and the pressure relief valve is connected to the bottom of the expansion chamber.

[0016] According to the above technical features, the beneficial effects of the present invention are as follows: compared with the prior art, the composite metal tube external seal of the present invention has an ultra-thin pipe body and a large diameter, and the two ends of the pipe string adopt a threaded structure without couplings, which can ensure that the large-diameter bridge plug is not blocked and also allow large-displacement construction during repeated fracturing; the composite metal rubber sleeve is composed of a composite of high-temperature and high-pressure resistant metal and rubber, which can avoid the aging of rubber under high temperature and high pressure, which leads to the weakening of the pressure difference resistance of the seal after the seal is set, the sealing time is short, and metal-to-metal sealing in the casing can be achieved, which can reach API 11D1 V0 level; the hydraulic expansion starting device can be controlled from the ground, and the composite metal rubber sleeve is expanded by hydraulic pressure. After expansion, it is tightly anchored and adhered to the inner wall of the outer casing; the valve system can lock the expansion liquid after the seal is expanded, and will not flow back when the pressure in the pipe is lower than the pressure in the rubber sleeve, and the expansion pressure is permanently maintained. The large-diameter composite metal pipe external packer body provided by the present invention has an external collapse resistance and internal pressure resistance that reaches or exceeds that of the tail pipe oil casing, and can perfectly replace expansion pipe patching, chemical plugging and tail pipe cement slurry injection. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the present invention;

[0018] Figure 2 Schematic diagram of the structure of the composite metal cartridge in the present invention.

[0019] In the figure: 1- pipe body; 2- composite metal rubber cylinder; 3- valve system; 4- hydraulic expansion starting device; 111- rubber cylinder; 112- metal ring. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0022] Example

[0023] Please refer to Figure 1-Figure 2 An embodiment of the present invention provides a large-diameter composite metal external pipe sealer for horizontal wellbore reconstruction, the device comprising: a tubing body 1, a composite metal rubber tube 2, a hydraulic expansion control device, and a valve system 3. The composite metal rubber tube 2 is sleeved on the outside of the tubing body 1; the hydraulic expansion control device is connected to the inside of the tubing body 1, the hydraulic expansion control device is electrically connected to the composite metal rubber tube 2 and arranged relative to each other, the hydraulic expansion control device is used to control the hydraulic pressure to expand the composite metal rubber tube 2; the valve system 3 is connected to the inside of the tubing body 1, the valve system 3 is used to lock the expansion liquid and maintain a constant expansion pressure.

[0024] It should be noted that the large-diameter composite metal external pipe packer provided by the present invention has an ultra-thin-wall structure of the pipe body 1, which ensures the smooth passage of the large-diameter bridge plug, thereby effectively adapting to the needs of large-displacement construction; the composite metal rubber cylinder 2 not only avoids the sealing failure caused by rubber aging, but also overcomes the problem of insufficient ductility of all-metal; the hydraulic expansion starting device 4 can accurately control the expansion process of the composite metal rubber cylinder 2 to ensure uniform sealing of the packer; the valve system 3 can automatically adjust the balance of internal and external pressures to ensure the stability of multiple fracturing operations. Compared with the existing technology, the present invention effectively improves the anti-external extrusion strength, anti-internal pressure strength and applicability of the packer for multiple fracturing, and can be better applied to the repeated transformation of old well reservoirs, solving the problems of short service life and small scope of application of the packer in the existing technology.

[0025] Specifically, the composite metal pipe external packer is connected to the inner casing. As the pipe string is lowered into the wellbore and reaches a fixed position, the hydraulic expansion starter 4 is activated through ground operation control, and the composite metal rubber tube 2 is expanded with the expansion liquid. The composite metal rubber tube 2 is in close contact with the inner wall of the casing, effectively blocking the perforations and effectively isolating the layers. The valve system 3 inside the composite metal pipe external packer can provide safety protection during construction. Then, after the packer expands, the expansion liquid is locked. When the pressure inside the pipe is lower than the pressure inside the composite metal rubber tube 2, the valve system 3 will ensure that the liquid does not flow back and the expansion pressure is permanently maintained. When the pressure inside the pipe is higher than the pressure inside the composite metal rubber tube 2, the valve system 3 will control the entry of liquid, ensuring the permanent expansion pressure of the composite metal rubber tube 2 and safeguarding the isolation capability of each layer.

[0026] It is worth noting that both ends of the tubular body 1 have threaded sections. The wall thickness of the tubular body 1 in conventional packers is 5-30mm, while the wall thickness of the tubular body 1 in the present invention is 2-13mm, which is an ultra-thin wall structure. By accurately calculating the relationship between the wall thickness and the anti-external extrusion strength, the tubular body can effectively increase the internal diameter while meeting the requirements of the anti-external extrusion strength and the internal pressure resistance. In detail, the packer adopts an ultra-thin wall thickness and large diameter structure, which can expand the central diameter (more than 30% more than the conventional one) while ensuring the pressure bearing (105MPa), so that the large diameter bridge plug (diameter ≥85mm) can pass through the inner hole of the packer smoothly to avoid obstruction; in addition, during large-displacement fracturing (displacement ≥12m 3 / min), the expanded cross-section reduces fluid friction, reduces turbulent loss in the fracturing fluid, and ensures high-speed passage of the sand-carrying fluid. The use of a coupling-free threaded connection structure reduces dimensional changes at the joint, avoiding the diameter restriction problem caused by the presence of couplings in conventional packers. This not only ensures the smooth passage of large-diameter tools, but also improves the fluid flow capacity during construction, thereby meeting the needs of high-displacement construction. The threaded section has been specially treated to provide excellent sealing performance and tensile strength, capable of withstanding working pressures up to 70 MPa. This not only simplifies construction procedures but also improves the reliability of the packer in multiple fracturing operations. Furthermore, in a certain test conducted by the applicant, the outer diameter of the tubing body 1 was 127 mm, the inner diameter was 114 mm, and the wall thickness was only 6.5 mm, which was approximately 30% less than the wall thickness of traditional packers, effectively increasing the internal diameter. The coupling-free threaded end structure avoids the problem of local dimensional increase caused by traditional couplings, allowing the packer to smoothly pass through narrow sections or complex wellbore structures downhole.

[0027] It is worth noting that the hydraulic expansion starting device 4 realizes the expansion process of the composite metal cartridge 2 through the precise operation of the ground control system. The device is arranged on the inner side of the middle part of the pipe body 1, and the expansion liquid is injected into the composite metal cartridge 2 through the hydraulic channel. The device can effectively improve the reliability under high temperature and high pressure environment. Optionally, the hydraulic expansion starting device 4 is made of high temperature and high pressure resistant materials, and by optimizing the hydraulic channel structure, it ensures that the expansion liquid can be evenly distributed inside the composite metal cartridge 2, thereby realizing the complete expansion of the composite metal cartridge 2 and close fit with the inner wall of the casing.

[0028] It is worth noting that conventional packers, when used in horizontal wellbore bends, can easily lead to uneven setting of the packer, making it difficult to cope with dynamic changes in formation pressure or repeated fracturing operations. The valve system 3 provided in the present invention enables bidirectional control, preventing the backflow of expansion fluid while also replenishing fluid to maintain the permanent expansion pressure of the composite metal cartridge 2, thereby ensuring its stability and reliability during multiple fracturing or acidizing operations.

[0029] Furthermore, the two valve systems 3 are respectively located on both sides of the hydraulic expansion starting device 4 .

[0030] Furthermore, the composite metal rubber cylinder 2 includes a rubber cylinder 111 and a plurality of metal rings 112 evenly connected to the outer circle of the rubber cylinder 111. The rubber cylinder 111 is made of elastic rubber resistant to high temperature and high pressure, and the metal rings 112 are made of metal resistant to high temperature and high pressure, which can overcome the limitations of a single material in extreme environments. The metal rings 112 are evenly distributed and connected to the outside of the rubber cylinder 111, and the ductility and pressure resistance of the rubber cylinder are enhanced through a specific arrangement, so that it can adapt to irregular well walls and achieve long-term sealing. Specifically, the rubber cylinder 111 is composed of a special elastic rubber, and its formula includes nitrile rubber, nano zinc oxide and plasticizer, of which nitrile rubber accounts for 70%, nano zinc oxide accounts for 15%, and plasticizer accounts for 15%. This combination of materials gives the rubber cylinder excellent high temperature resistance (maximum temperature resistance can reach 180 degrees Celsius) and high pressure resistance (maximum pressure resistance can reach 100 MPa). Metal ring 112 is 2 mm thick and 10 mm wide and is fixed to the surface of rubber cylinder 111 via laser welding. It supports rubber cylinder 111 during expansion, preventing it from failing due to excessive deformation. The distribution density and thickness of metal ring 112 are optimized to ensure close contact between rubber cylinder 111 and the inner wall of the sleeve during expansion, achieving an efficient seal while maintaining sufficient mechanical strength.

[0031] Furthermore, the hydraulic expansion control device includes at least a hydraulic pump, hydraulic piping, an expansion chamber, and a pressure sensor. The shape of the expansion chamber matches the rubber cylinder 111. The hydraulic expansion starting device 4 drives the rubber cylinder 111 to expand through ground-controlled hydraulic pressure, causing it to tightly fit the inner wall of the casing. The hydraulic expansion starting device 4 mainly includes three parts: a hydraulic pump, a hydraulic piping, and an expansion chamber. The hydraulic pump is connected to the ground equipment and is connected to the expansion chamber inside the packer via a hydraulic piping. In a certain test conducted by the applicant, the maximum output pressure of the hydraulic pump was 120 MPa, which can meet the construction requirements under different working conditions. The expansion chamber is located inside the tubing body 1 and its shape matches the rubber cylinder 111, ensuring that the hydraulic liquid is evenly distributed and pushing the rubber cylinder 111 outward to expand. In actual operation, the ground control equipment sends a command to the hydraulic pump, which injects hydraulic liquid into the expansion chamber. The pressure of the liquid gradually increases, pushing the rubber cylinder 111 outward to expand until it completely fits the inner wall of the casing. During this process, the hydraulic expansion and activation device 4 precisely controls the expansion speed and pressure of the rubber cylinder 111, ensuring uniform and stable setting of the packer. Furthermore, the hydraulic expansion and activation device 4 is equipped with a pressure sensor that monitors pressure changes within the expansion chamber in real time and transmits this data to the surface control system, allowing operators to adjust construction parameters in a timely manner.

[0032] Furthermore, valve system 3 includes at least a one-way valve, a pressure regulating valve, and a pressure relief valve connected to the rubber cylinder 111. The one-way valve is connected between the hydraulic line and the expansion chamber, and the pressure relief valve is connected to the bottom of the expansion chamber. The one-way valve prevents hydraulic fluid from flowing back, ensuring that the pressure in the expansion chamber remains at the set value. The pressure regulating valve automatically adjusts the pressure in the expansion chamber to maintain equilibrium with the downhole ambient pressure. In an experiment conducted by the applicant, the pressure regulating valve had a response time of 0.5 seconds, enabling rapid response to pressure fluctuations and ensuring the stability of the packer. The pressure relief valve is used to release the hydraulic fluid in the expansion chamber after the operation is completed, allowing the rubber cylinder 111 to return to its original state. During operation, valve system 3: when the surface hydraulic pump injects hydraulic fluid into the expansion chamber, the one-way valve opens, allowing the fluid to enter the expansion chamber and push the rubber cylinder 111 to expand. When the pressure in the expansion chamber reaches the set value, the pressure regulating valve automatically closes, locking in the expansion fluid and maintaining a constant pressure. After the operation is completed, the operator opens the pressure relief valve through the surface control system, releasing the fluid in the expansion chamber and returning the rubber cylinder 111 to its original state. This design not only simplifies the construction steps, but also improves the applicability of the packer in multiple fracturing operations.

[0033] In detail, the large-diameter composite metal tube external packer of the present invention can be used for repeated reconstruction of old well reservoirs. Taking a horizontal well as an example, the inner diameter of the casing of the well is 124 mm, the well depth is 3,000 meters, the reservoir temperature is 150 degrees Celsius, and the reservoir pressure is 50 MPa. Before construction, the operator assembles the packer into a complete tool string through the threaded section and lowers it into the predetermined position in the wellbore. Subsequently, the ground hydraulic pump is started and hydraulic liquid is injected into the hydraulic expansion starting device 4. The liquid pressure gradually increases to 80 MPa, pushing the composite metal rubber cylinder 2 to expand outward and fit tightly to the inner wall of the casing. During this process, the pressure sensor monitors the pressure changes in the expansion chamber in real time and transmits the data to the ground control system. The operator adjusts the output pressure of the hydraulic pump according to the data to ensure that the packer is sealed evenly and stably. After the packer is sealed, volume fracturing construction is carried out with a construction displacement of 10 cubic meters per minute and a construction pressure of 70 MPa. After the operation was completed, the operator opened the pressure relief valve through the ground control system, releasing the hydraulic fluid in the expansion chamber and returning the composite metal rubber cartridge 2 to its original state, completing the fracturing operation. During the multiple fracturing operations, the packer demonstrated excellent resistance to external collapse and internal pressure, without any seal failure or structural damage, effectively improving the efficiency of reservoir reconstruction in the old well.

[0034] Furthermore, in order to further verify the performance that can be achieved by the structure of the present invention, the applicant conducted a number of experimental tests. In a high-temperature and high-pressure experiment, the packer was placed in an experimental device that simulated the downhole environment. The ambient temperature was 180 degrees Celsius, the ambient pressure was 100 MPa, and the duration was 24 hours. The experimental results showed that the composite metal rubber cylinder 2 can still maintain good sealing performance under extreme conditions, without any aging or deformation. In another multiple fracturing experiment, the packer performed 10 consecutive fracturing operations, with a pressure of 70 MPa and a displacement of 10 cubic meters per minute for each operation. The experimental results show that the packer showed excellent stability and reliability in multiple fracturing operations, without any uneven sealing or sealing failure. These experimental data can effectively demonstrate the efficiency and reliability of the present invention in practical applications.

[0035] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all points of view, the embodiments should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and range of equivalents of the claims are included in the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0036] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A large-diameter composite metal pipe external packer for horizontal wellbore reconstruction, characterized in that: include: Pipe string body(1); A composite metal rubber cylinder (2), wherein the composite metal rubber cylinder (2) is sleeved on the outside of the pipe column body (1); A hydraulic expansion control device, the hydraulic expansion control device being connected to the interior of the pipe column body (1), the hydraulic expansion control device being electrically connected to the composite metal rubber tube (2) and being arranged opposite to each other, the hydraulic expansion control device being used to control the hydraulic pressure so as to expand the composite metal rubber tube (2); A valve system (3) is connected to the interior of the tubular column body (1), and the valve system (3) is used to lock the expansion liquid and maintain a constant expansion pressure.

2. The packer according to claim 1, characterized in that The two valve systems (3) are respectively located on both sides of the hydraulic expansion starting device (4).

3. The packer according to claim 1, wherein: Both ends of the pipe column body (1) are provided with threaded sections.

4. The packer according to claim 1, wherein: The composite metal rubber cylinder (2) comprises a rubber cylinder (111) and a plurality of metal rings (112) connected to the outer circumference of the rubber cylinder (111) at even intervals.

5. The packer according to claim 4, characterized in that The hydraulic expansion control device comprises at least a hydraulic pump, a hydraulic pipeline, an expansion chamber and a pressure sensor, and the shape of the expansion chamber matches the rubber cylinder (111).

6. The packer according to claim 5, characterized in that The valve system (3) comprises at least a one-way valve, a pressure regulating valve and a pressure relief valve connected to a rubber cylinder (111), wherein the one-way valve is connected between the hydraulic pipeline and the expansion chamber, and the pressure relief valve is connected to the bottom of the expansion chamber.

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