Tool and method for repairing annulus under pressure

Abstract

The invention discloses a tool and a method for repairing annulus under pressure. The tool comprises a body, and a drilling assembly, a trepanning assembly, a repairing assembly and a first setting device which are sequentially arranged on the body from top to bottom, the perforating assembly is used for perforating the production casing; the drilling and removing assembly is used for penetrating through the hole to drill and remove the cement sheath to form a repairing hole channel; the repairing assembly comprises a heater and a starter; the heater is arranged in the first cavity of the body, and a storage mechanism is formed between the heater and the body; the storage mechanism is used for storing the fusible metal blocks and communicates with the outside. The heater is used for containing heating fuel; the starter is arranged at the top end of the heater and is started based on a starting signal transmitted externally, the heating fuel is activated, and then the fusible metal block is melted through the heating fuel to form metal fluid; the first setting device is used for fixing the position of the tool and enabling the metal fluid flowing out of the storage mechanism to enter the repairing channel through the hole under blocking of the first setting device. And the repairing effect can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas well completion, and in particular to a tool and method for repairing annular pressure. Background Art

[0002] With the continuous development of oil and gas exploration and development, the exploitation of natural gas reservoirs has received more and more attention from various countries. At present, the exploitation depth of natural gas wells is continuously increasing, but most of them face harsh environments such as high temperature and high pressure underground and even corrosive gases, and these high temperature and high pressure gas wells generally have the problem of annular pressure.

[0003] The annular pressure problem is very detrimental to production safety and is a common problem faced by the petroleum industry. Annular pressure will reduce the recovery rate of gas wells, seriously affect the production of gas wells, and will have an adverse impact on subsequent operations of gas field development, such as acid fracturing. When the annular pressure is not obvious, the cost of wellhead annular pressure monitoring and pressure relief will increase, and in severe cases, it will lead to well closure and abandonment of the entire well. For example, in a certain area, many of the more than 18,000 wells with surface casing annular pressure must be shut in, and some wells even need to be shut down and scrapped.

[0004] There are two main reasons for the annular pressure of gas wells: one is the failure of the oil pipe string, usually in the form of failure of the threaded connection of the pipe string and the seal of the packer, which causes the gas in the production layer to flow into the oil casing annulus (annulus A) and gather at the wellhead to generate annular pressure. In this case, the pressure differential activation plugging technology is generally used. The pressure differential activation plugging agent dehydrates and activates the central particles in the pressure differential flow field at the leaking points such as the casing thread. The active particles aggregate and fill the leaking pores to achieve adaptive plugging. This method has been successfully applied in the Gulf of Mexico, the Netherlands, Louisiana in the United States, Kazakhstan, and Australia, and this method has a high success rate and low cost; the second is the failure of the cement ring seal. Due to the presence of some tiny gaps inside the cement ring, the high-pressure gas downhole seeps along these gaps to the wellhead of the casing annulus (annulus B), generating annular pressure. Later stage treatment generally requires perforating, squeezing plugging agents, and installing partitions to allow plugging agents to enter the gas channel, and form partitions after the plugging agents solidify to control the annular pressure; among them, the plugging agents used in the prior art are generally cement or resin. Summary of the invention

[0005] The inventors of the present application have discovered that the existing methods for solving the annulus pressure problem caused by cement ring sealing failure have the problem of annulus pressure still existing after the plugging operation due to the random distribution of gas channeling channels in the cement ring and the limited number of gas channeling channels that cannot be hit by perforating. In addition, when the plugging agent used for plugging in the prior art is cement slurry, the cement slurry has the problem of poor fluidity and difficulty in squeezing into micro-cracks, and the cement is easily corroded by corrosive gases downhole. After a period of time, new cracks may be generated to cause annulus pressure, and the plugging effect is poor. Although the resin has strong permeability, it requires a long solidification time. Therefore, the existing methods for solving the sealing failure of the cement ring have the disadvantages of poor sealing effect and long construction period.

[0006] In view of the above problems, the present invention is proposed to provide a tool and method for repairing annular pressure that overcomes the above problems or at least partially solves the above problems.

[0007] The embodiment of the present invention provides a tool for repairing annular pressure, comprising: a body and a drilling assembly, a hole opening assembly, a repair assembly and a first sealing device sequentially arranged on the body from top to bottom;

[0008] The hole-opening assembly is used for opening holes in the production casing;

[0009] The drilling assembly is used to drill the cement ring through the hole to form a repair channel;

[0010] The repair component includes: a heater and a starter;

[0011] The heater is disposed in the first cavity of the body and forms a storage mechanism with the body;

[0012] The storage mechanism is used to store the fusible metal block and is connected to the outside; the heater is used to hold the heating fuel; the starter is arranged at the top of the heater to start and activate the heating fuel based on the start signal transmitted from the outside, and then melt the fusible metal block through the heating fuel to form a metal fluid;

[0013] The first sealing device is used to fix the position of the tool, and allows the metal fluid flowing out of the storage mechanism to enter the repair channel through the hole under the obstruction of the first sealing device.

[0014] In an optional embodiment, at least one fluid inlet is provided on the upper end surface of the body, and a fluid outlet corresponding to the fluid inlet is provided on the side wall;

[0015] The drilling assembly comprises: a fluid flow channel connecting the fluid inlet and the corresponding fluid outlet, a universal shaft and a turbine disposed in the fluid, and a drilling drill bit is connected to the front end of the universal shaft;

[0016] The turbine sleeve is arranged on the universal shaft to drive the universal shaft and the drilling bit to move under the action of hydraulic pressure, and the cement ring is drilled through the hole to form a repair channel.

[0017] In an optional embodiment, the fusible metal block includes: a binary eutectic alloy of bismuth and germanium, a binary eutectic alloy of bismuth and copper, a binary eutectic alloy of bismuth and tin, or a binary eutectic alloy of bismuth and silver.

[0018] In an optional embodiment, the heating fuel includes: thermite powder and thermite pellets;

[0019] The thermite blocks are stacked inside the heater, and the thermite powder is disposed on the top of the thermite blocks, so that the thermite powder is stimulated by a starter to generate a high temperature to ignite the thermite blocks.

[0020] In an optional embodiment, a screen is provided at the lower end of the first cavity, and the storage mechanism is connected to the outside through the screen;

[0021] Accordingly, the metal fluid flows out of the storage mechanism through the screen.

[0022] In an optional embodiment, the fluid flow channel includes: a straight section, a tapered section, and a curved section connected in sequence from top to bottom;

[0023] The direct current section is connected to the end of the tapered section with a larger diameter, and the curved section is connected to the end of the tapered section with a smaller diameter;

[0024] The turbine is threadedly engaged with the inner wall of the direct current section, and the conical section is used to limit the downward movement of the turbine.

[0025] In an optional embodiment, the universal joint of the universal shaft is provided with flow channels that are interconnected;

[0026] The drilling bit is a diamond drill bit, and a nozzle is arranged at the center of the drilling bit.

[0027] In an optional embodiment, the hole-opening assembly is disposed in the second cavity of the body, and includes: a hole-opening drill bit, a drill rod, a hydraulic device and a screw motor;

[0028] A window is provided on the side wall of the body for the drill rod to extend out;

[0029] One end of the drill rod is connected to the hole-opening drill bit, and the other end is connected to the piston rod of the hydraulic device to drive the drill rod to move through the hydraulic device; the side wall of the drill rod is meshed with the screw gear of the screw motor to drive the drill rod to rotate through the screw motor.

[0030] In an optional embodiment, the diameter of the hole-opening drill bit is larger than the diameter of the removal drill bit.

[0031] In an optional embodiment, the inner hole of the guide is connected to the flow channel to guide the movement of the universal shaft.

[0032] In an optional embodiment, the center line of the inner hole of the guide is arranged at a preset angle with the center line of the body.

[0033] In an optional embodiment, the annulus pressure repair tool provided in the embodiment of the present invention further includes: a second setting device and a third setting device;

[0034] The second sealing device is arranged at the upper end of the body, and the third sealing device is arranged between the opening component and the repair component.

[0035] Based on the same inventive concept, an embodiment of the present invention also provides a method for repairing annular pressure based on the above-mentioned tool for repairing annular pressure, comprising:

[0036] The tool is lowered to a first preset position in the production casing, and after the tool is set, at least one hole is opened in the production casing using a hole opening assembly;

[0037] After the hole-opening process of the casing is completed, the tool is released from the setting, the tool is controlled to move downward to the second preset position, the tool is set, and the drilling assembly is used to drill the cement ring through the hole to form a repair channel;

[0038] After the drilling of the repair channel is completed, the tool is released from the sealing, the tool is lifted to the third preset position, the tool position is fixed by the first sealing device, and the fusible metal block in the storage mechanism is heated and melted by the heating component to form a metal fluid. After the metal fluid flows out of the storage mechanism, it flows into the repair channel in the cement ring and the gas channel in the cement ring connected to the repair channel through the hole under the blocking of the first sealing device;

[0039] The first sealing device is sheared off by using a well repair tool and the tool is lifted to the ground, and a sealing body is formed after the metal fluid is cooled to realize the repair of the annular space with pressure.

[0040] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0041] The tool for repairing annular pressure provided by an embodiment of the present invention comprises: a main body and a drilling assembly, a hole-opening assembly, a repair assembly and a first sealing device which are sequentially arranged on the main body from top to bottom; the device uses the hole-opening assembly to drill holes in the casing, and uses the drilling assembly to penetrate the holes to drill the cement ring to form a repair channel; at the same time, the device activates a heating fuel through a starter to heat and melt the fusible metal block in the storage mechanism to form a metal fluid, so that it replaces the sealing effect of the original cement ring. Compared with the existing method of using cement slurry or resin as a sealing material, the time for the fusible metal to cool and solidify from the liquid to form a metal sealing body is shorter, and the metal sealing body established after the fusible metal is cooled has good sealing performance, high pressure bearing capacity and good corrosion resistance. Therefore, using the tool provided by the embodiment of the present invention, the overall sealing effect of the cement ring can be improved and the operation time can be reduced, that is, the repair effect and efficiency of the cement ring annular pressure can be effectively improved.

[0042] At the same time, compared with the existing method of perforating the cement sheath, the tool for repairing annular pressure provided by the embodiment of the present invention is capable of creating a large-volume channel on the cement sheath between the sleeves in the universal shaft and the drilling bit of the drilling assembly, and after the drilling bit touches the casing after drilling in the cement sheath for a period of time, the drill bit and the universal shaft turn because the hardness of the casing is much greater than that of the cement, and continue to drill between the casings on both sides to form a spiral repair channel, and as the drilling bit goes deeper into the cement sheath, more and more gas channel are connected to the channel, which can improve the ability of the plugging material to fill the gas channel, and further improve the repair effect of the cement sheath annular pressure.

[0043] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0044] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0046] Figure 1 This is a schematic diagram of the structure of a tool for repairing annular pressure in an embodiment of the present invention;

[0047] Figure 2 It is a schematic diagram of the local structure of the tool for repairing annular pressure in an embodiment of the present invention when the casing is perforated;

[0048] Figure 3It is a schematic diagram of the partial structure of the tool for repairing annular pressure in an embodiment of the present invention in a cement drilling and removal state;

[0049] Figure 4 It is a schematic diagram of the partial structure of the tool for repairing annular pressure in an embodiment of the present invention in a state of metal burning and melting plugging;

[0050] Figure 5 It is a side view of the drill head crushing cement stone in an embodiment of the present invention.

[0051] Description of reference numerals:

[0052] 1. Main body; 2. Drilling assembly; 3. Opening assembly; 4. Repair assembly; 5. First setting device; 6. Second setting device; 7. Third setting device; 8. Production casing; 9. Technical casing; 10. Cement ring;

[0053] 21. Universal joint; 22. Drilling bit; 23. Guide; 24. Fluid flow channel; 25. Turbine; 31. Drill bit; 32. Screw motor; 33. Hydraulic device; 34. Drill rod; 41. Heater; 42. Storage mechanism; 43. Metal block; 44. Starter; 45. Screen; 102. Second cavity. DETAILED DESCRIPTION

[0054] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0055] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0056] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0057] In the prior art, in order to solve the annulus pressure problem caused by cement ring sealing failure, perforation is generally used to open the casing and cement ring, and plugging materials are injected into the damaged cement ring for repair. However, the holes formed by perforation cannot allow the plugging materials to flow into the crossflow channel efficiently and in large volumes, which may lead to problems such as insufficient pressure bearing strength of the plugging body and poor air tightness.

[0058] Therefore, in order to solve the problems existing in the prior art of treating cement ring seal failure, such as poor sealing effect, long construction period, great difficulty, high cost of single well operation, etc., the embodiments of the present invention provide a tool and method for repairing annulus pressure, so as to treat the annulus pressure problem caused by the failure of cement ring seal in old wells and realize the reconstruction of the wellbore integrity of the old well.

[0059] The tool for repairing annular pressure provided by the embodiment of the present invention is referred to Figures 1 to 4 As shown, it comprises: a main body 1 and a drilling assembly 2, a hole opening assembly 3, a repair assembly 4 and a first sealing device 5 which are sequentially arranged on the main body 1 from top to bottom;

[0060] The hole-opening assembly 3 is used to open holes in the production casing 8;

[0061] The drilling assembly 2 is used to drill through the hole to remove the cement ring 10 between the production casing 8 and the technical casing 9 to form a repair channel;

[0062] The repair component 4 includes: a heater 41 and a starter 44;

[0063] The heater 41 is disposed in a first cavity (not shown in the figure) of the body 1 and forms a storage mechanism 42 with the body 1;

[0064] The storage mechanism 42 is used to store the fusible metal block 43 and is connected to the outside. The heater 41 is used to contain the heating fuel. The starter 44 is arranged at the top of the heater 41 to start and activate the heating fuel based on the start signal transmitted from the outside, and then melt the fusible metal block 43 to form a metal fluid by the heating fuel.

[0065] The first setting device 5 is used to fix the tool position and allow the metal fluid flowing out of the storage mechanism 42 to enter the repair channel through the hole under the obstruction of the first setting device 5.

[0066] The tool for repairing annular space pressure provided in an embodiment of the present invention melts the low-melting-point metal in the tool through the heater 41, so that it replaces the sealing function of the original cement ring 10. It takes a short time for the fusible metal to cool and solidify from the liquid state to form a metal sealing body, and a metal sealing body with good sealing performance and high pressure bearing capacity can be established in the annulus between the sleeves, which can shorten the repair time of the annular space pressure problem and improve the repair effect of the annular space pressure.

[0067] Among them, the embodiment of the present invention does not specifically limit the specific shape of the fusible metal block 43. It can be a whole block structure, a multi-block structure of different sizes, or a metal ball structure of different sizes, etc., which can be selected according to actual needs.

[0068] In one embodiment, the fusible metal used as the plugging material in this embodiment can be a low melting point, high strength metal. It only takes a few minutes for the low melting point metal to cool and solidify from the liquid state to form a metal plugging body; wherein, the fusible metal in this embodiment, for example, can be: a binary eutectic alloy of bismuth and germanium, a binary eutectic alloy of bismuth and copper, a binary eutectic alloy of bismuth and tin, or a binary eutectic alloy of bismuth and silver. In this embodiment, the type of alloy selected in practical applications is not specifically limited, and the specific melting point of each fusible metal selected is related to the components of the alloy and the proportion of each component, and can be selected according to actual needs; the inventor of this application found in the study that the melting point of the above alloy is approximately between 95°C and 240°C, and the alloy will expand by 1%-3.3% when solidifying from liquid to solid, which enables the alloy to fully fit the surrounding environment, firmly seal a specific space in the form of interference fit, and can well meet the sealing requirements of the cement ring 10.

[0069] In one embodiment, the heating fuel contained in the heater 41 may specifically be: thermite powder and thermite pellets;

[0070] Thermite blocks are stacked inside the heater 41, and thermite powder is arranged on the top of thermite blocks, so that thermite powder is stimulated by the starter 44 to generate high temperature to ignite thermite blocks; since thermite powder is relatively sensitive, it is arranged on the top of the fuel cavity of the heater 41, and can be stimulated by ignition with a small current, and the high temperature generated by thermite powder continues to ignite the thermite charge column adjacent to it, and then the thermite blocks stacked inside start a self-propagating reaction from the top. The storage mechanism is arranged in the annulus between the heater 41 and the body 1, and is used to store low-melting-point metal pellets. Since the high temperature of thermite reaction is about 1200°C, thermite is used as a heating fuel, and the continuous heat release of thermite can melt all the low-melting-point metal pellets outside the heater 41. Accordingly, the heater 41 in this embodiment is a thermite reaction heater 41.

[0071] Furthermore, the starter 44 of this embodiment is connected to a cable, and an electrical signal is transmitted through the cable to control the starter 44 to activate the fuel inside the heater 41.

[0072] In one embodiment, referring to Figure 1 and Figure 4 As shown, a screen is provided at the lower end of the first cavity;

[0073] A storage mechanism 42 is formed between the main body 1 , the heater 41 and the screen 45 , and the storage mechanism 42 is connected to the outside through the screen 45 ; accordingly, the metal fluid flows out of the storage mechanism 42 through the screen 45 .

[0074] In one embodiment, referring to Figure 1 and Figure 2 As shown, the hole-opening assembly 3 is disposed in the second cavity 102 of the main body 1, and includes: a hole-opening drill bit 31, a drill rod 34, a hydraulic device 33 and a screw motor 32;

[0075] A window is provided on the side wall of the body 1 for the drill rod 34 to extend out;

[0076] One end of the drill rod 34 is connected to the hole drill bit 31, and the other end is connected to the piston rod of the hydraulic device 33, so that the drill rod 34 can be driven to move through the hydraulic device 33; the side wall of the drill rod 34 is meshed with the screw gear of the screw motor 32, so that the drill rod 34 can be driven to rotate through the screw motor 32.

[0077] In this embodiment, when it is necessary to perform casing hole drilling operation, the screw motor 32 and the hydraulic device 33 receive external control signals to start working, and the drilling drill bit 31 performs casing hole drilling through the drilling pressure and torque provided by the downhole screw motor 32 and the hydraulic device 33. After the hole drilling is completed, based on the received external control signal, the screw motor 32 stops working, and the oil in the hydraulic cylinder of the hydraulic device 33 flows back, so that the piston rod is retracted, and the drill rod 34 is pulled back at the same time, thereby resetting the drilling drill bit 31. Among them, the casing hole drilling assembly 3 needs to drill multiple holes in different directions at different well depths. Specifically, the tool can be rotated and positioned and sealed multiple times through ground control to achieve multiple hole drilling operations.

[0078] Furthermore, the hole drill bit 31 can be a spade drill bit, and the drill bit material is a composite carbide of hard metal and high-speed steel, which reduces the phenomenon of tooth collapse during hole drilling and improves the hole drilling success rate and the service life of the drill bit. When drilling holes in the production casing 8, the rotation speed can be selected to be 150-200r / m, and the drilling pressure is 60-80KN. At this time, it takes 10-20 minutes to drill through the N80 and P110 casings using the hole drill bit 31.

[0079] In one embodiment, referring to Figure 1 and Figure 3As shown, at least one fluid inlet is provided on the upper end surface of the body 1, and a fluid outlet corresponding to the fluid inlet is provided on the side wall;

[0080] The drilling assembly 2 comprises: a fluid flow channel 24 connecting a fluid inlet and a corresponding fluid outlet, a universal shaft 21 and a turbine 25 arranged in the fluid, and a drilling drill bit 22 is connected to the front end of the universal shaft 21;

[0081] The turbine 25 is sleeved on the universal shaft 21 to drive the universal shaft 21 and the drilling bit 22 to move under the action of hydraulic pressure, and drill the cement ring 10 through the hole to form a repair channel.

[0082] The tool provided in this embodiment controls the drill bit to reset after the hole is drilled in the casing; the tool is unsealed and the tool is moved downward for a distance so that the drilling bit 22 of the drilling assembly 2 is aligned with the hole drilling position. After the tool is resealed, the universal shaft 21 is sent into the cement ring 10 through the hole to drill out the cement. The drilling assembly 2 of this embodiment drives the drilling bit 22 to drill in the cement ring 10 for a period of time through the universal shaft 21 and then hits the casing. Since the hardness of the casing is much greater than that of the cement, the drilling bit 22 and the universal shaft 21 turn and continue to drill between the casings on both sides to create a large volume channel on the cement ring 10 between the casings. As the drill bit goes deeper into the cement ring 10, more and more gas channeling channels are connected to the channel, which can improve the ability of the plugging material to fill the gas channeling channel.

[0083] Furthermore, the universal joint 21 in this embodiment can adopt a cross-axis rigid universal joint or a ball cage universal joint to transmit drilling pressure and torque. Specifically, the cross-axis universal joint is composed of a cross shaft, two universal joint forks and needle bearings, etc. The holes on the two universal joint forks are respectively sleeved on the two pairs of journals of the cross shaft. In order to reduce friction loss and improve transmission efficiency, a needle bearing composed of a needle roller and a sleeve is installed between the cross shaft journal and the universal joint fork hole. The screw and the bearing cover fix the sleeve on the universal joint fork, and the screw is locked with a locking plate to prevent the bearing from coming out of the universal joint fork under the action of centrifugal force. In this way, when the driving shaft rotates, the driven shaft can rotate with it and swing in any direction around the center of the cross shaft.

[0084] Optionally, the universal joint of the universal shaft 21 may be provided with interconnected flow channels. During the process of drilling and removing cement, the fluid can flow out through the connection between adjacent universal joints. The pressure difference of the fluid flushes the channel wall and discharges cement stone debris, while providing lubrication for itself to reduce friction resistance.

[0085] The surface material and structure of the universal shaft 21 are not specifically limited in the embodiment of the present invention and can be selected according to actual needs to reduce the friction resistance during the rotary drilling process.

[0086] Specifically, in this embodiment, the turbine 25 is composed of blades, a disk, a housing and other components. Among them, the blades are the most critical parts, and their design and manufacturing quality directly affect the performance and service life of the turbine 25; the disk plays the role of supporting and rotating the blades, and bears the centrifugal force and inertial force of the blades. The housing plays the role of sealing and guiding, ensuring that the working fluid flows inside the turbine 25. Furthermore, the blades of the turbine 25 can adopt a hollow structure to reduce the mass and inertia of the blades. The cross-section of the blade is in a gradually tapering shape to reduce the aerodynamic resistance and inertial force of the blade. The surface of the blade adopts a streamlined design to reduce the friction resistance and shape resistance of the fluid. The turbine 25 disk is made of steel, and its structure is a plate shell structure or a turbine 25 disk structure. The surface is treated with a high-temperature alloy surface to improve its heat resistance and fatigue resistance.

[0087] In one embodiment, referring to Figure 1 and Figure 3 As shown, the fluid flow channel 24 may include: a straight section, a tapered section, and a curved section sequentially connected from top to bottom;

[0088] The direct current section is connected to the end of the tapered section with a larger diameter, and the curved section is connected to the end of the tapered section with a smaller diameter;

[0089] The turbine 25 is threadedly engaged with the inner wall of the direct current section, and the conical section is used to limit the downward movement of the turbine 25 .

[0090] The fluid flow channel 24 of the embodiment of the present invention is provided with a tapered section and a curved section at the lower part, which can also guide the movement of the universal shaft 21, so as to avoid the phenomenon of winding and the like during the rotation of the universal shaft 21, which deviates from the movement direction and affects the drilling effect of the cement sheath 10. The embodiment of the present invention does not specifically limit the number and distribution of the fluid flow channels 24, for example, it can be set to 4, and the 4 fluid flow channels 24 are evenly arranged on the upper part of the body 1. Among them, each fluid flow channel 24 is equipped with a universal shaft 21 and multiple turbines 25, the shell of the turbine 25 is threadedly engaged with the inner wall of the direct current section in the fluid flow channel 24, and the wheel disc of the turbine 25 is locked with the universal shaft 21; when the high-pressure fluid is pumped into the ground, the upper and lower pressure differences cause the impeller and wheel disc of the turbine 25 to rotate, and then drive the universal shaft 21 to rotate, and the shell of the turbine 25 moves downward under the action of the oblique thread during the rotation process, providing the required drilling pressure and torque for drilling, and when the turbine 25 moves to the conical section of the fluid flow channel, it is blocked by the conical section, that is, the universal shaft extends into place and stops moving forward; accordingly, at this time, according to the changes in the fluid medium parameters (such as pressure, fluid flow rate, etc.) detected by the wellhead detection instrument, the pumping of high-pressure fluid can be controlled to stop. Preferably, when the fluid flow channel 24 is set to two or more, each fluid flow channel 24 is not connected to each other.

[0091] In one embodiment, the drilling bit 22 may be a diamond-impregnated drill bit with a nozzle disposed at the center of the drill bit. During the drilling process of the cement sheath 10 , the fluid flowing through the fluid channel 24 may be used as a coolant to cool the drill bit and assist in breaking the cement sheath 10 .

[0092] Furthermore, when the turbine 25 drives the universal shaft 21 and the drilling bit 22 to move under the action of hydraulic pressure, the high-pressure fluid pumped from the ground can be specifically 15% to 30% hydrochloric acid. The high-pressure fluid enters the fluid flow channel 24 at a preset pressure (for example, 20 MPa), drives the turbine 25 to rotate, and the acid flows into the repair channel in the cement ring 10, corroding the cement stone to expand the channel volume; and the acid sprayed from the drilling bit 22 can soften the cement stone and increase the mechanical drilling speed.

[0093] It should be noted that all working components working in an acid environment need to be sprayed with an anti-corrosion coating. The commonly used anti-corrosion treatment methods in the prior art are chrome-nickel plating and special anti-corrosion coating processes. The anti-corrosion coatings used in general oil fields are mainly epoxy phenolic resins with other organic polymer anti-corrosion resins such as ketone aldehydes added. The coating is resistant to chemical media, and its coating is hard and has good adhesion. It has excellent corrosion resistance, salt water resistance and oil resistance, and is suitable for the protection and anti-corrosion of the surfaces of various metal structures. Therefore, in this embodiment, the body 1, the universal shaft 21, the drilling bit 22, the turbine 25, the fluid flow channel 24 and other components need to be sprayed with an anti-corrosion coating.

[0094] Furthermore, the diameter of the hole-opening drill bit 31 of the tool provided in this embodiment needs to be larger than the diameter of the drilling bit 22. Preferably, the size of the hole formed after the hole is opened is much larger than the diameter of the drilling bit 22, so that after the subsequent assembly is moved down, drilling can be started without precise alignment with the casing hole. Among them, the embodiment of the present invention does not limit the specific sizes of the hole-opening drill bit 31 and the drilling bit 22, which can be selected according to actual needs. For example, the diameter of the hole-opening drill bit 31 can be approximately 40 mm, and the diameter of the drilling bit 22 can be approximately 10 mm.

[0095] In one embodiment, referring to Figure 1 and Figure 3 As shown, a guide 23 may also be provided on the side wall of the body 1;

[0096] The inner hole of the guide 23 is communicated with the flow channel to guide the movement of the universal shaft 21 .

[0097] Furthermore, the center line of the inner hole of the guide 23 can be arranged at a preset angle with the center line of the body 1 .

[0098] The guide 23 can fix the initial position of the universal shaft 21 and the drill bit 22 to ensure that the drill bit can align with the position of the casing hole. Since the cement ring 10 between the sleeves is thin, the effective footage of vertical drilling is small. Therefore, the guide 23 can be set with an inclination angle so that the drill bit drills into the cement ring 10 at a certain angle. The final channel can be spiral. Figure 5 As shown in , the formed pore volume is larger, which is conducive to the subsequent inflow and plugging of molten metal.

[0099] In one embodiment, referring to Figure 1 As shown, the tool provided by the embodiment of the present invention further includes: a second setting device 6 and a third setting device 7;

[0100] The second setting device 6 is arranged at the upper end of the body 1 , and the third setting device 7 is arranged between the opening component 3 and the repair component 4 .

[0101] Specifically, the second sealing device 6 and the third sealing device 7 are used to seal the tool when drilling holes in the casing and drilling out the cement ring 10 to form a repair channel; wherein the first sealing device 5, the second sealing device 6 and the third sealing device 7 can specifically be spring bridge plugs, and the process of sealing and releasing the tool by the first sealing device 5, the second sealing device 6 and the third sealing device 7 can refer to the existing technology, and the embodiment of the present invention does not make specific limitations on this.

[0102] In one embodiment, the implementation of the tool provided by the embodiment of the present invention is exemplarily described as follows:

[0103] (1) First, the best repair section for gas channeling of cement sheath 10 is determined by using logging technology, and then the tool is lowered to the pre-drilled well section through the oil pipe, and the tool is set by using the second setting device 6 and the third setting device 7 to fix the position of the tool.

[0104] (2) Start the screw motor 32 and the hydraulic device 33 of the hole-opening assembly 3 to provide torque and drilling pressure for the hole-opening drill bit 31, mill and open holes on the casing, and control the rotation or downward movement of the tool on the ground to open multiple holes at different well depths and orientations.

[0105] (3) After completing the drilling of the casing hole, release the tool sealing and move the tool downward, align the drilling assembly 2 with the drilling position, make the position of the drilling bit 22 of the drilling assembly 2 correspond to the height and orientation of the relative position of the formed hole, and then use the second sealing device 6 and the third sealing device 7 to seal the tool.

[0106] (4) High-pressure fluid is pumped into the ground, and the turbine 25 drives the universal shaft 21 and the drilling bit 22 to drill into the cement ring 10 under the action of the pressure difference. The guide 23 is used to provide preliminary orientation for the drilling bit 22, so that the universal shaft 21 can continue to enter during the drilling process to form a repair channel in the cement ring 10.

[0107] (5) Release the tool seal, lift the entire pipe string and lift the repair component 4 to the well section to be plugged, use the first sealing device 5 to seal the tool, heat and melt the metal block 43 in the storage mechanism 42, and the liquefied metal flows out through the screen 45 and then flows into the channels and gas channel in the cement ring 10 through the holes. Then, use the well repair tool to cut off the first sealing device 5 and lift it up as a whole for recovery. After the metal cools, it forms a high-strength sealing body.

[0108] Based on the same inventive concept, an embodiment of the present invention further provides a method for repairing annular pressure based on the above-mentioned tool for repairing annular pressure, comprising the following steps:

[0109] The tool is lowered to a first preset position in the production casing, and after the tool is set, at least one hole is opened in the production casing using the opening assembly;

[0110] After the hole opening process of the casing is completed, the tool is released from the setting, the tool is controlled to move down to the second preset position, the tool is set and the drilling assembly is used to drill through the hole to drill out the cement ring to form a repair channel;

[0111] After the drilling of the repair channel is completed, the tool is released from the sealing, the tool is lifted to the third preset position, the tool position is fixed by the first sealing device, and the fusible metal block in the storage mechanism is heated and melted by the heating component to form a metal fluid. After the metal fluid flows out of the storage mechanism, it flows into the repair channel in the cement ring and the gas channel in the cement ring connected to the repair channel through the hole under the blocking of the first sealing device;

[0112] The first sealing device is sheared off using the workover tool and the tool is lifted to the ground. After the metal fluid cools down, a sealing body is formed to repair the annular pressurized space.

[0113] Among them, the specific positions of the first preset position, the second preset position, and the third preset position can be set according to the situation of the wellbore to be repaired, and the embodiment of the present invention does not make specific limitations; among them, the first preset position is specifically a preset opening position in the best repair section for cement ring gas leakage determined by using logging technology.

[0114] Regarding the method for repairing annular pressure based on the above-mentioned tool for repairing annular pressure in the above-mentioned embodiment, the specific process has been described in detail in the embodiment of the above-mentioned tool for repairing annular pressure, and will not be elaborated here.

[0115] The embodiment of the present invention provides a metal repair tool and method for annular space under pressure, which removes and replaces the cement ring with a certain thickness that fails to seal with a metal plugging body. The specific process of using the tool to repair the annular space under pressure is as follows: first, the tool body is lowered to the preset position, and after the tool is sealed, the casing is opened using the hole drill bit, and the tool can be rotated and positioned and sealed multiple times through ground control as needed to achieve multiple openings, and then the tool is released from anchoring, and the tool is moved down to align the drilling drill bit of the drilling assembly with the hole opening position, so that the universal shaft and the drilling drill bit are drilled into the cement ring between the technical casing and the production casing to form a repair channel, and finally the low-melting-point, high-strength metal stored at the lower end of the tool is used as a plugging material, which is heated and melted underground and squeezed into the annulus, and a high-strength plugging body is formed after cooling to achieve long-term and effective plugging of the annular space under pressure.

[0116] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0117] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0118] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments may be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," is explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to mean "non-exclusive or".

Claims

1. A tool for repairing annular pressure. It is characterized in that include: A main body and a drilling assembly, a hole opening assembly, a repair assembly and a first sealing device which are sequentially arranged on the main body from top to bottom; The hole-opening assembly is used for opening holes in the production casing; The drilling assembly is used to drill the cement ring through the hole to form a repair channel; The repair component includes: a heater and a starter; The heater is disposed in the first cavity of the body and forms a storage mechanism with the body; The storage mechanism is used to store the fusible metal block and is connected to the outside; the heater is used to hold the heating fuel; the starter is arranged at the top of the heater to start and activate the heating fuel based on the start signal transmitted from the outside, and then melt the fusible metal block through the heating fuel to form a metal fluid; The first sealing device is used to fix the position of the tool, and allows the metal fluid flowing out of the storage mechanism to enter the repair channel through the hole under the obstruction of the first sealing device.

2. The tool according to claim 1, It is characterized in that The upper end surface of the body is provided with at least one fluid inlet, and the side wall is provided with a fluid outlet corresponding to the fluid inlet; The drilling assembly comprises: a fluid flow channel connecting the fluid inlet and the corresponding fluid outlet, a universal shaft and a turbine disposed in the fluid, and a drilling drill bit is connected to the front end of the universal shaft; The turbine sleeve is arranged on the universal shaft to drive the universal shaft and the drilling bit to move under the action of hydraulic pressure, and the cement ring is drilled through the hole to form a repair channel.

3. The tool according to claim 1, It is characterized in that The fusible metal block includes a binary eutectic alloy of bismuth and germanium, a binary eutectic alloy of bismuth and copper, a binary eutectic alloy of bismuth and tin, or a binary eutectic alloy of bismuth and silver.

4. The tool according to claim 1, It is characterized in that The heating fuel includes: thermite powder and thermite pills; The thermite blocks are stacked inside the heater, and the thermite powder is disposed on the top of the thermite blocks, so that the thermite powder is stimulated by a starter to generate a high temperature to ignite the thermite blocks.

5. The tool according to claim 1, It is characterized in that A screen is provided at the lower end of the first cavity, and the storage mechanism is connected to the outside through the screen; Accordingly, the metal fluid flows out of the storage mechanism through the screen.

6. The tool according to claim 2, It is characterized in that The fluid flow channel comprises: a straight section, a tapered section and a curved section which are sequentially connected from top to bottom; The direct current section is connected to the end of the tapered section with a larger diameter, and the curved section is connected to the end of the tapered section with a smaller diameter; The turbine is threadedly engaged with the inner wall of the direct current section, and the conical section is used to limit the downward movement of the turbine.

7. The tool according to claim 2, It is characterized in that The universal joint of the universal shaft is provided with flow passages interconnected with each other; The drilling bit is a diamond drill bit, and a nozzle is arranged at the center of the drilling bit.

8. The tool according to claim 1, It is characterized in that The hole-opening assembly is disposed in the second cavity of the body, and includes: a hole-opening drill bit, a drill rod, a hydraulic device and a screw motor; A window is provided on the side wall of the body for the drill rod to extend out; One end of the drill rod is connected to the hole-opening drill bit, and the other end is connected to the piston rod of the hydraulic device to drive the drill rod to move through the hydraulic device; the side wall of the drill rod is meshed with the screw gear of the screw motor to drive the drill rod to rotate through the screw motor.

9. The tool according to claim 8, It is characterized in that The diameter of the hole-opening drill bit is larger than the diameter of the removal drill bit.

10. The tool according to claim 1, It is characterized in that A guide is also provided on the side wall of the body; The inner hole of the guide is communicated with the flow channel to guide the movement of the universal shaft.

11. The tool according to claim 10, It is characterized in that The center line of the inner hole of the guide is arranged at a preset angle with the center line of the body.

12. A tool according to any one of claims 1 to 11, It is characterized in that Also includes: a second setting device and a third setting device; The second sealing device is arranged at the upper end of the body, and the third sealing device is arranged between the opening component and the repair component.

13. A method for repairing annular pressure. It is characterized in that A tool for repairing annular pressure according to any one of claims 1 to 11 is implemented, comprising: The tool is lowered to a first preset position in the production casing, and after the tool is set, at least one hole is opened in the production casing using a hole opening assembly; After the hole-opening process of the casing is completed, the tool is released from the setting, the tool is controlled to move downward to the second preset position, the tool is set, and the drilling assembly is used to drill the cement ring through the hole to form a repair channel; After the drilling of the repair channel is completed, the tool is released from the sealing, the tool is lifted to the third preset position, the tool position is fixed by the first sealing device, and the fusible metal block in the storage mechanism is heated and melted by the heating component to form a metal fluid. After the metal fluid flows out of the storage mechanism, it flows into the repair channel in the cement ring and the gas channel in the cement ring connected to the repair channel through the hole under the blocking of the first sealing device; The first sealing device is sheared off by using a well repair tool and the tool is lifted to the ground, and a sealing body is formed after the metal fluid is cooled to realize the repair of the annular space with pressure.

Images