Apparatus and method for downhole casing damage repair

Abstract

The device comprises a sleeve, a rotating mechanism, a centering mechanism, a positioning mechanism, a hole expanding mechanism, a die attaching mechanism and a grouting mechanism, and the hole expanding mechanism is used for forming expanded holes in a damaged sleeve and a cement sheath outside the damaged sleeve; the die attaching mechanism comprises a die plate and a die attaching driving piece, and the die attaching driving piece is used for driving the die plate to be attached and sealing the reamed hole. And the grouting mechanism is used for injecting cement paste into the reamed hole. A damaged area is reamed through the reaming mechanism, a corrosion structure is removed, the contact area between the damaged area and cement paste and the flatness degree of the contact position are increased, the cement paste and the damaged part can be combined more firmly, the pressure bearing capacity of the repaired casing is effectively improved, and the service life of the casing is prolonged. The problem that in a traditional repairing method, the pressure bearing capacity is low is solved, the risk that the casing pipe is damaged again due to insufficient pressure bearing is reduced, and the stability of oilfield exploitation operation is guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum pipe repair, and in particular to a device and method for repairing downhole casing damage. Background Art

[0002] In the process of oil and gas field exploitation, the geological conditions are quite complex, and inclined wells and horizontal wells are common, which leads to frequent damage to oil well casing. Damage to oil well casing will bring many hazards to oil field development: 1) The production string cannot be lowered into the well normally, hindering the exploitation operation; 2) If the damaged part of the casing is in the water layer or sand layer, the oil well will produce a large amount of water or sand, seriously affecting the quality and output of crude oil production; 3) Various oil well production increase measures are difficult to implement, limiting the improvement of oil field production capacity; 4) It is very easy to cause blowout outside the casing, posing a major threat to exploitation safety; 5) It may even lead to the scrapping of the oil well, resulting in a double loss of resources and economy.

[0003] For the problem of casing rupture, squeezing cement slurry is a relatively common repair method. This method can be used for repair when the reservoir pressure is relatively small and the rupture and leakage are not very serious. The specific process is as follows: First, use a well gauge that is 8-10 mm smaller than the inner diameter of the casing to perform the diameter operation to ensure that the wellbore is unobstructed. Then, insert the suspended plug at the appropriate position of the rupture to temporarily seal the wellbore below the rupture. Then, inject an appropriate amount of cement slurry above the bridge plug to solidify it to form a cement plug. After the cement plug solidifies, drill out the cement plug in the casing and test the sealing quality of the cement on the rupture through pressure testing. After confirming that the sealing quality meets the standard, drill out the suspended plug (bridge plug) and perform sand flushing operations until the bottom of the well. Under normal circumstances, the casing repaired by this method can withstand a pressure of 40-80 MPa. However, in the subsequent high-pressure construction, a packer needs to be lowered for protection to prevent the repair section from being subjected to excessive pressure.

[0004] However, this repair method has certain defects:

[0005] 1. The rupture and leakage areas were not pre-treated, and the bond with the squeezed cement slurry was not strong enough, resulting in low pressure bearing capacity of the casing.

[0006] 2. In the process of drilling the suspended plug, in order to avoid damaging the casing, the borehole diameter is usually smaller than the inner diameter of the casing, which will lead to a reduction in the effective diameter of the casing and may have an adverse effect on subsequent operations such as running the tubing string.

[0007] 3. The drilling operation may damage the structure of the cement plug, thereby affecting the structural strength of the cement plug and reducing its sealing effect. Summary of the invention

[0008] The purpose of the present invention is to overcome the above-mentioned technical deficiencies, propose a device and method for repairing downhole casing damage, and solve the technical problems in the prior art of casing rupture repair, such as the rupture and leakage points are not firmly bonded with the cement slurry resulting in low pressure bearing capacity, drilling open the suspended plug will reduce the effective aperture of the casing and affect subsequent operations, and the cement plug structure is damaged to reduce the sealing effect.

[0009] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0010] The present invention provides a device for repairing casing damage in a well, comprising:

[0011] A sleeve, the sleeve being used for rotationally connecting to one end of the coiled tubing;

[0012] a rotating mechanism, the rotating mechanism being connected to both the sleeve and the coiled tubing and being used for driving the sleeve to rotate relative to the coiled tubing;

[0013] A centering mechanism, which is mounted on the sleeve and is used to center the sleeve at the damaged sleeve;

[0014] A positioning mechanism, the positioning mechanism is mounted on the sleeve and is used to position the damaged area of ​​the damaged sleeve;

[0015] A hole expansion mechanism, which is installed on the sleeve and is used to expand the damaged area of ​​the damaged casing to form an expanded hole in the damaged casing and in the cement ring outside the damaged casing;

[0016] A die sticking mechanism, the die sticking mechanism comprising a template and a die sticking driving member, the die sticking driving member being connected to the template and used to drive the template to stick and close the expanded hole; and

[0017] A grouting mechanism is used to inject cement slurry into the expanded hole.

[0018] In some embodiments, the sleeve is used to be connected to one end of the coiled tubing via a rotary joint, the fixed end of the rotary joint is fixedly connected to the coiled tubing, and the rotating end of the rotary joint is fixedly connected to the sleeve;

[0019] The rotating mechanism includes a sleeve, a fixed ring, a gear ring, a rotating motor and a gear. The sleeve is sleeved on the coiled tubing and fixedly connected to the fixed end of the rotating joint. The fixed ring is fixedly sleeved on the sleeve. The gear ring is fixed to the fixed ring. The fixed end of the rotating motor is fixed to the sleeve. The output end of the rotating motor is coaxially fixedly connected to the gear, and the gear is meshed with the gear ring.

[0020] In some embodiments, the centering mechanism includes a plurality of supporting members, each of which includes a swing arm, a roller, a cylinder and an air pump. One end of the swing arm is hinged to the outer wall of the sleeve, the roller is installed at the other end of the swing arm, the fixed end of the cylinder is hinged to the outer wall of the sleeve, the output end of the cylinder is hinged to the swing arm, and the outlet of the air pump is connected to the air inlet of the cylinder.

[0021] In some embodiments, the positioning mechanism includes a plurality of cameras, a plurality of fill light components and an image processor, each of the cameras is mounted on the outer wall of the sleeve, each of the fill light components is used to fill light for the corresponding camera, the image processor is electrically connected to each of the cameras, and is used to obtain the depth and orientation of the damaged area of ​​the damaged sleeve based on the images taken by each of the cameras.

[0022] In some embodiments, the reaming mechanism includes a first fixed plate, a first slider, a reaming motor, a reaming drill bit and a reaming pushing cylinder, the first fixed plate is fixed in the sleeve, the first slider is slidably disposed on the first fixed plate, the fixed end of the reaming motor is fixed to the first slider, the reaming drill bit is fixed to the output end of the reaming motor, the fixed end of the reaming pushing cylinder is fixed to the sleeve, and the movable end of the reaming pushing cylinder is connected to the fixed end of the reaming motor and is used to drive the fixed end of the reaming motor to move.

[0023] In some embodiments, a closed water passage cavity is formed in the sleeve, and the rotary joint is connected to the water passage cavity;

[0024] The reaming mechanism also includes a spray assembly, which includes a spray head, a connecting pipe and a valve body. The spray head is fixed to the sleeve, and the outlet of the spray head is arranged laterally and not above the reaming drill bit. One end of the connecting pipe is connected to the water chamber, and the other end of the connecting pipe is connected to the water inlet end of the spray head. The valve body is arranged on the connecting pipe.

[0025] In some embodiments, the template is arc-shaped and can fit the inner wall of the damaged casing. The template is provided with grouting holes and exhaust holes. The grouting mechanism is used to inject cement slurry into the expanded hole through the grouting holes.

[0026] In some embodiments, the mold driving component includes a second fixed plate, a second slider, a pushing rod and a mold driving cylinder, the second fixed plate is fixed in the sleeve, the second slider is slidably arranged on the second fixed plate, one end of the pushing rod is fixed to the second slider, the other end of the pushing rod is fixed to the template, the fixed end of the mold driving cylinder is fixed to the sleeve, and the output end of the mold driving cylinder is fixedly connected to the second slider.

[0027] In some embodiments, a closed slurry chamber is also formed in the sleeve;

[0028] The grouting mechanism comprises a grouting pump and a grouting pipe, the inlet of the grouting pump is communicated with the slurry cavity, and the outlet of the grouting pump is communicated with the grouting hole.

[0029] The present invention also provides a method for repairing downhole casing damage, which is applicable to the device for repairing downhole casing damage, and comprises the following steps:

[0030] Device installation and lowering: Install the damaged casing repair device at the lower end of the coiled tubing, and use the coiled tubing to drive the entire device to move downward in the damaged casing;

[0031] Centering and positioning: During the downward movement of the device, the centering mechanism plays a role in placing the device at the center of the damaged casing to ensure the accuracy of subsequent operations. At the same time, the positioning mechanism continuously detects the damaged casing. When the positioning mechanism detects the damaged area, it immediately locates the damaged area.

[0032] Azimuth adjustment and hole expansion: According to the positioning result of the positioning mechanism, the rotating mechanism starts to work and drives the sleeve to rotate, so that the position of the hole expansion mechanism, the mold sticking mechanism and the grouting mechanism is consistent with the position of the damaged area. Then, according to the position information determined by the positioning, the coiled tubing is lowered to a specific length, so that the hole expansion mechanism is first accurately aligned with the damaged area, and then the hole expansion mechanism expands the damaged area of ​​the damaged casing and the cement ring outside the damaged casing to form an expanded hole;

[0033] Formwork and grouting: After the hole expansion is completed, the coiled tubing is lowered again to a specific length so that the formwork mechanism is aligned with the damaged area, and the formwork drive drives the template to fit and close the hole expansion. After that, the coiled tubing is lowered again to a specific length so that the grouting mechanism is aligned with the damaged area, and cement slurry is injected into the hole expansion;

[0034] Subsequent operations: After the cement slurry solidifies, the mold-sticking mechanism releases the template, and the device continues to move downward through the continuous oil pipe to carry out the next inspection and repair operation of the damaged area.

[0035] Compared with the prior art, the damaged casing repair device provided by the present invention has the following beneficial effects:

[0036] (1) Enhanced bonding strength and pressure bearing capacity: The damaged area is enlarged by the hole enlarging mechanism, which not only removes the corrosion structure, but also increases the contact area and flatness of the contact between the damaged area and the cement slurry. Compared with the traditional method where the rupture and leakage are not pretreated, the cement slurry can be more firmly bonded to the damaged area, effectively improving the pressure bearing capacity of the casing after repair, solving the problem of low pressure bearing capacity in traditional repair methods, reducing the risk of casing damage due to insufficient pressure bearing, and ensuring the stability of oilfield production operations.

[0037] (2) Avoiding the reduction of effective aperture: This technical solution does not require drilling a suspended plug like the traditional method, thus avoiding the problem of the effective aperture of the casing being reduced due to the borehole diameter being smaller than the inner diameter of the casing. This ensures that subsequent operations such as string running can proceed smoothly without being hindered by the reduction of the aperture, ensuring the smoothness of the mining operation process and improving the operation efficiency.

[0038] (3) Ensure the structural strength and sealing effect of the cement plug: Since the suspended plug is not drilled, the cement plug structure will not be damaged, thereby ensuring the structural strength of the cement plug and improving its sealing effect. This helps to better seal the damaged parts and prevent problems such as water, sand, and blowout in the oil well, improve the quality of repair, extend the service life of the oil well, reduce the possibility of oil well scrapping due to poor repair quality, and reduce resource and economic losses. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a reference diagram of the use state of a damaged casing repair device provided by one embodiment of the present invention;

[0040] Figure 2 yes Figure 1 A schematic diagram of the structure of the damaged casing repair device;

[0041] Figure 3 yes Figure 2 A partial enlarged view of the middle area A;

[0042] Figure 4 yes Figure 2 A partial enlarged view of the middle area B;

[0043] Figure 5 yes Figure 2 A partial enlarged view of the middle area C;

[0044] Description of reference numerals: 1-sleeve, 11-water chamber, 12-slurry chamber, 13-protective plate, 2-rotating mechanism, 21-shaft sleeve, 22-fixing ring, 23-gear ring, 24-rotating motor, 25-gear, 3-centering mechanism, 31-support, 311-swing arm, 312-roller, 313-cylinder, 314-air pump, 4-positioning mechanism, 41-camera, 42-fill light, 5-hole expansion mechanism, 51-first fixing plate, 52-first slider, 53-hole expansion motor, 54- Reaming drill bit, 55-reaming push cylinder, 56-spray assembly, 561-spray head, 562-connecting pipe, 563-valve body, 6-mold sticking mechanism, 61-template, 611-grouting hole, 612-exhaust hole, 62-mold sticking drive member, 621-second fixed plate, 622-second slider, 623-push rod, 624-mold sticking drive cylinder, 7-grouting mechanism, 71-grouting pump, 72-grouting pipe, 8-continuous oil pipe, 81-swivel joint, 9-damaged casing, 91-cement ring. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0046] In order to solve the technical problems in the prior art of casing rupture repair, the rupture and leakage are not firmly combined with cement slurry, resulting in low pressure bearing capacity, drilling open the suspended plug will reduce the effective aperture of the casing and affect subsequent operations, and the cement plug structure is damaged and the sealing effect is reduced. The present invention provides a device and method for repairing casing damage in the well.

[0047] See also Figure 1-Figure 5 , Figure 1 Schematic diagram of the structure of a damaged casing repair device in one embodiment of the present invention, the damaged casing repair device includes a sleeve 1, a rotating mechanism 2, a centering mechanism 3, a positioning mechanism 4, a hole expanding mechanism 5, a mold sticking mechanism 6 and a grouting mechanism 7.

[0048] The sleeve 1 is used for being rotatably connected to one end of the coiled tubing 8 .

[0049] The rotating mechanism 2 is connected to both the sleeve 1 and the coiled tubing 8 , and is used to drive the sleeve 1 to rotate relative to the coiled tubing 8 .

[0050] The centering mechanism 3 is mounted on the sleeve 1 and is used to center the sleeve 1 at the damaged sleeve.

[0051] The positioning mechanism 4 is installed on the sleeve 1 and is used to position the damaged area of ​​the damaged sleeve.

[0052] The reaming mechanism 5 is installed on the sleeve 1 and is used to reame the damaged area of ​​the damaged casing to form an reamed hole in the damaged casing and in the cement ring outside the damaged casing.

[0053] The mold sticking mechanism 6 includes a mold plate 61 and a mold sticking driving member 62. The mold sticking driving member 62 is connected to the mold plate 61 and is used to drive the mold plate 61 to stick to and close the expanded hole.

[0054] The grouting mechanism 7 is used to inject cement slurry into the expanded hole.

[0055] The usage process includes the following steps:

[0056] (1) Installation and lowering of the device: The damaged casing repair device is installed at the lower end of the coiled tubing 8, and the entire device is driven to move downward in the damaged casing 9 by the coiled tubing 8.

[0057] (2) Centering and positioning: During the downward movement of the device, the centering mechanism 3 plays a role in positioning the device at the center of the damaged casing to ensure the accuracy of subsequent operations. At the same time, the positioning mechanism 4 continuously detects the damaged casing. When the positioning mechanism 4 detects the damaged area, it immediately positions the damaged area.

[0058] (3) Azimuth adjustment and hole enlargement: Based on the positioning result of the positioning mechanism 4, the rotating mechanism 2 starts to work and drives the sleeve 1 to rotate, so that the positions of the hole enlargement mechanism 5, the mold sticking mechanism 6 and the grouting mechanism 7 are consistent with the position of the damaged area. Then, according to the position information determined by the positioning, the coiled tubing 8 is lowered to a specific length, so that the hole enlargement mechanism 5 is first accurately aligned with the damaged area, and then the hole enlargement mechanism 5 performs hole enlargement operation on the damaged area of ​​the damaged casing 9 and the cement ring 91 outside the damaged casing, thereby forming an enlarged hole.

[0059] (4) Forming and grouting: After the hole is expanded, the coiled tubing 8 is lowered again to a specific length so that the forming mechanism 6 is aligned with the damaged area, and the forming drive 62 drives the template 61 to fit and close the expanded hole. After that, the coiled tubing 8 is lowered again to a specific length so that the grouting mechanism 7 is aligned with the damaged area, and cement slurry is injected into the expanded hole.

[0060] (5) Subsequent operation: After the cement slurry solidifies, the mold sticking mechanism 6 releases the mold plate 61, and the device continues to move downward through the continuous oil pipe 8 to perform the next inspection and repair operation of the damaged area.

[0061] The technical effects of the above scheme include:

[0062] (1) Enhanced bonding strength and pressure bearing capacity: The damaged area is expanded by the expansion mechanism 5, which not only removes the corrosion structure, but also increases the contact area and flatness of the contact between the damaged area and the cement slurry. Compared with the traditional method where the rupture and leakage are not pretreated, the cement slurry can be more firmly combined with the damaged part, effectively improving the pressure bearing capacity of the casing after repair, solving the problem of low pressure bearing capacity in the traditional repair method, reducing the risk of casing damage again due to insufficient pressure bearing, and ensuring the stability of oilfield production operations.

[0063] (2) Avoiding the reduction of effective aperture: This technical solution does not require drilling a suspended plug like the traditional method, thus avoiding the problem of the effective aperture of the casing being reduced due to the borehole diameter being smaller than the inner diameter of the casing. This ensures that subsequent operations such as string running can proceed smoothly without being hindered by the reduction of the aperture, ensuring the smoothness of the mining operation process and improving the operation efficiency.

[0064] (3) Ensure the structural strength and sealing effect of the cement plug: Since the suspended plug is not drilled, the cement plug structure will not be damaged, thereby ensuring the structural strength of the cement plug and improving its sealing effect. This helps to better seal the damaged parts and prevent problems such as water, sand, and blowout in the oil well, improve the quality of repair, extend the service life of the oil well, reduce the possibility of oil well scrapping due to poor repair quality, and reduce resource and economic losses.

[0065] It should be understood that continuous tubing technology is an important technology in oil and gas field exploitation and related operations. Continuous tubing, also known as flexible tubing and coiled tubing, is a long tubing that can be continuously wound on a reel. It is usually made of high-strength alloy steel, has good flexibility and strength, and can be smoothly lowered or pulled out in a complex wellbore environment. During the operation of the continuous tubing, special continuous tubing operation equipment is used to achieve its lifting and lowering movements. The equipment is mainly composed of a continuous tubing drum, an injection head, a blowout preventer group, a power system and other parts. The continuous tubing drum is used to wind and release the continuous tubing, and the injection head provides the power required for the continuous tubing to be lowered into or pulled out of the wellbore. The continuous tubing is clamped by a chain plate or a clamp to achieve its smooth lifting and lowering movement. The blowout preventer group is used to control the wellhead pressure to ensure the safety of the operation. The power system provides power support for the entire equipment.

[0066] Coiled tubing technology has been widely used in the oil and gas industry and is a conventional technical means. Therefore, this article will not describe the lifting structure of the coiled tubing in detail, but will focus on the damaged casing repair device based on the coiled tubing and its unique working principle and technical effect.

[0067] In one embodiment, see Figure 1 , Figure 2 and Figure 5The sleeve 1 is used to be connected to one end of the coiled tubing 8 via a rotary joint 81, the fixed end of the rotary joint 81 is fixedly connected to the coiled tubing 8, and the rotating end of the rotary joint 81 is fixedly connected to the sleeve 1; the rotating mechanism 2 includes a sleeve 21, a fixed ring 22, a gear ring 23, a rotary motor 24 and a gear 25, the sleeve 21 is sleeved on the coiled tubing 8 and fixedly connected to the fixed end of the rotary joint 81, the fixed ring 22 is fixedly sleeved on the sleeve 21, the gear ring 23 is fixed to the fixed ring 22, the fixed end of the rotary motor 24 is fixed to the sleeve 1, the output end of the rotary motor 24 is coaxially fixedly connected to the gear 25, and the gear 25 is meshed with the gear ring 23.

[0068] In this embodiment, the sleeve 21 is sleeved on the continuous oil pipe 8 and fixed to the fixed end of the rotary joint 81, so that the sleeve 21 can move with the movement of the continuous oil pipe 8. The fixed ring 22 is fixedly sleeved outside the sleeve 21 to stabilize the structure. The ring gear 23 is fixed on the fixed ring 22 and moves synchronously with the fixed ring 22. The rotating motor 24 is fixed on the sleeve 1, and its output end is coaxially fixedly connected to the gear 25, and the gear 25 and the ring gear 23 are meshed with each other. When the rotating motor 24 is started, the motor output shaft drives the gear 25 to rotate. Since the gear 25 is meshed with the ring gear 23, the ring gear 23 rotates under the drive of the gear 25. Because the gear ring 23 is fixed on the fixing ring 22 connected to the sleeve 21, the sleeve 21 is connected to the coiled tubing 8, and the sleeve 1 is connected to the coiled tubing 8 through the rotary joint 81, the rotation of the gear ring 23 will drive the entire sleeve 1 to rotate relative to the coiled tubing 8, thereby adjusting the orientation of the expansion mechanism 5, the mold attachment mechanism 6, the grouting mechanism 7 and other components installed on the sleeve 1 to make them consistent with the orientation of the damaged area.

[0069] By connecting the sleeve 1 and the coiled tubing 8 through the rotary joint 81 and cooperating with the components in the rotary mechanism 2, the sleeve 1 can be flexibly rotated relative to the coiled tubing 8, and the orientation of various repair components installed on the sleeve 1 can be accurately adjusted to accurately align the damaged area of ​​the damaged casing, thereby improving the accuracy of the repair operation. This flexible orientation adjustment capability helps to quickly and accurately repair damaged areas in different orientations in a complex wellbore environment, avoiding the problem of repair failure or poor repair effect caused by inaccurate component orientation.

[0070] In one embodiment, see Figure 1-Figure 3The centering mechanism 3 includes a plurality of support members 31, each of which includes a swing arm 311, a roller 312, a cylinder 313 and an air pump 314. One end of the swing arm 311 is hinged to the outer wall of the sleeve 1, and the roller 312 is installed on the other end of the swing arm 311. The fixed end of the cylinder 313 is hinged to the outer wall of the sleeve 1, the output end of the cylinder 313 is hinged to the swing arm 311, and the outlet of the air pump 314 is connected to the air inlet of the cylinder 313.

[0071] In this embodiment, the centering mechanism realizes the automatic centering of the damaged casing repair device in the damaged casing through the coordinated work of multiple support members 31. The air pump 314 supplies air to the cylinder 313, and the output end of the cylinder 313 pushes the swing arm 311 to swing around its hinge point with the sleeve 1, so that the roller 312 installed at the other end of the swing arm 311 contacts the inner wall of the damaged casing. Since multiple support members 31 are evenly distributed on the outer wall of the sleeve 1, they work together to enable the entire device to automatically adjust its position and always maintain the center position of the damaged casing. This greatly improves the stability and centering accuracy of the repair device in the casing, ensures that subsequent operations such as reaming, die pasting and grouting can be carried out accurately, avoids repair position deviation due to device offset, and improves the repair quality. The design of the swing arm 311 and the roller 312 of the support member 31 enables the mechanism to adapt to damaged casings of different inner diameters. When entering casings of different inner diameters, the cylinder 313 can adjust the extension angle of the swing arm 311 according to actual conditions, so that the roller 312 fits tightly against the inner wall of the casing. This adaptive capability enhances the versatility of the repair device, eliminating the need for frequent replacement of components or complex adjustments for casings with different inner diameters, reducing the cost of equipment use and expanding its scope of application. It can be applied to oil well casing repair work of various specifications.

[0072] In one embodiment, see Figure 1 and Figure 2 The positioning mechanism 4 includes a plurality of cameras 41, a plurality of fill-light components 42 and an image processor. Each of the cameras 41 is mounted on the outer wall of the sleeve 1. Each of the fill-light components 42 is used to fill light for the corresponding camera 41. The image processor is electrically connected to each of the cameras 41 and is used to obtain the depth and orientation of the damaged area of ​​the damaged sleeve based on the images taken by each of the cameras 41.

[0073] In this embodiment, the plurality of cameras 41 in the positioning mechanism 4 are evenly distributed along the outer circumference of the sleeve 1 and are installed on the outer wall of the sleeve 1. When the damaged casing repair device moves down in the damaged casing along with the continuous oil pipe, the camera 41 continuously captures the internal image of the damaged casing. At the same time, the fill light 42 fills the light for the corresponding camera 41 to ensure that the camera 41 can still capture a clear image when there is insufficient light in the wellbore. The image processor is electrically connected to each camera 41 to receive and process the image captured by the camera 41. When a camera 41 captures the damaged part, the sleeve 1 is first rotated by the rotating mechanism 2, and the damaged area is brought to the center of the field of view of the camera 41 by means of the lifting and lowering of the continuous oil pipe. Since the system pre-stores the azimuth and height difference of each camera 41 relative to the reaming mechanism 5, the mold attachment mechanism 6 and the grouting mechanism 7, the image processor determines the azimuth and depth of the damaged area relative to the sleeve 1 according to the preset parameters of the camera 41.

[0074] The beneficial effects of this embodiment are as follows: through multiple cameras 41 evenly distributed along the outer circumference of the sleeve 1, the damaged casing can be photographed in all directions, reducing the blind spots in the shooting and ensuring that the damaged area will not be missed. In combination with the fill light 42 to ensure clear imaging, the image processor can accurately determine the position and depth of the damaged area relative to the sleeve 1 based on the image taken by the camera 41 and the preset azimuth and height difference parameters. This provides accurate position information for the subsequent reaming mechanism 5, mold attachment mechanism 6 and grouting mechanism 7 to accurately reach the damaged area for repair work, greatly improving the accuracy of the repair work and avoiding the occurrence of repair failure or poor repair effect due to inaccurate positioning.

[0075] In one embodiment, see Figure 1 and Figure 2The reaming mechanism 5 includes a first fixed plate 51, a first slider 52, a reaming motor 53, a reaming drill 54 and a reaming push cylinder 55. The first fixed plate 51 is fixed in the sleeve 1. The first slider 52 is slidably arranged on the first fixed plate 51. The fixed end of the reaming motor 53 is fixed to the first slider 52. The reaming drill 54 is fixed to the output end of the reaming motor 53. The fixed end of the reaming push cylinder 55 is fixed to the sleeve 1. The movable end of the reaming push cylinder 55 is connected to the fixed end of the reaming motor 53 and is used to drive the fixed end of the reaming motor 53 to move. When in use, when the reaming mechanism 5 reaches the position of the damaged area, the reaming push cylinder 55 starts to work, and its movable end extends to push the reaming motor 53 and the first slider 52 to slide on the first fixed plate 51, thereby adjusting the distance between the reaming drill 54 and the damaged area, so that the reaming drill 54 contacts the damaged area. Subsequently, the reaming motor 53 is started, driving the reaming drill bit 54 to rotate at high speed, while the movable end of the reaming push cylinder 55 continues to extend, reaming the damaged area of ​​the damaged casing and the cement ring outside the damaged casing until the desired reaming is formed.

[0076] In one embodiment, see Figure 1 and Figure 2 A closed water passage chamber 11 is formed in the sleeve 1, and the rotary joint 81 is connected to the water passage chamber 11; the reaming mechanism 5 also includes a spray assembly 56, and the spray assembly 56 includes a nozzle 561, a connecting pipe 562 and a valve body 563. The nozzle 561 is fixed to the sleeve 1, and the outlet of the nozzle 561 is arranged laterally and not above the reaming drill bit 54. One end of the connecting pipe 562 is connected to the water passage chamber 11, and the other end of the connecting pipe 562 is connected to the water inlet end of the nozzle 561. The valve body 563 is arranged on the connecting pipe 562.

[0077] In this embodiment, the rotary joint 81 is connected to the closed water passage chamber 11 in the sleeve 1, and water is introduced into the upper end of the continuous oil pipe 8. When water flows through the rotary joint 81 inside the continuous oil pipe 8, the water will enter the water passage chamber 11. Before the reaming mechanism 5 is ready to reame the damaged area, the valve body 563 is in a closed state. When the reaming mechanism 5 moves to the damaged area and starts the reaming operation, the valve body 563 is opened. At this time, the water in the water passage chamber 11 flows to the nozzle 561 through the connecting pipe 562. Since the nozzle 561 is fixed on the sleeve 1 and the outlet is laterally arranged above the reaming drill bit 54, water is sprayed from the nozzle 561 and directly sprayed on the working part of the reaming drill bit 54. During the reaming process, continuous spraying cools the reaming drill bit 54 and promptly washes away the debris generated by reaming to ensure the smooth progress of the reaming operation. After the reaming is completed, the debris in the reaming is cleaned to prevent the debris from affecting the casing repair effect.

[0078] In one embodiment, see Figure 1-Figure 4 The template 61 is arc-shaped and can fit the inner wall of the damaged casing. The template 61 is provided with a grouting hole 611 and an exhaust hole 612. The grouting mechanism 7 is used to inject cement slurry into the expanded hole through the grouting hole 611. In this embodiment, the template 61 is designed to be arc-shaped and can fit the inner wall of the damaged casing, so that the template and the inner wall of the casing are in close contact, which can effectively block the expanded hole area and provide a good sealing environment for subsequent grouting. The close fit can prevent the cement slurry from leaking from the gap between the template and the casing wall during the injection process, ensuring that the cement slurry accurately fills the expanded hole space and improves the repair effect.

[0079] In one embodiment, see Figure 1-Figure 4 The mold driving component 62 includes a second fixed plate 621, a second slider 622, a pushing rod 623 and a mold driving cylinder 624. The second fixed plate 621 is fixed in the sleeve 1, and the second slider 622 is slidably set on the second fixed plate 621. One end of the pushing rod 623 is fixed to the second slider 622, and the other end of the pushing rod 623 is fixed to the template 61. The fixed end of the mold driving cylinder 624 is fixed to the sleeve 1, and the output end of the mold driving cylinder 624 is fixedly connected to the second slider 622.

[0080] In this embodiment, when the reaming mechanism 5 completes the reaming operation, the continuous oil pipe 8 is lowered to make the mold-attaching mechanism 6 reach the position of the damaged area, and the mold-attaching driving cylinder 624 is started. The output end of the mold-attaching driving cylinder 624 pushes the second slider 622 to slide along a specific direction on the second fixed plate 621. Since the push rod 623 connects the second slider 622 and the template 61, the sliding of the second slider 622 drives the push rod 623 to move, and then pushes the template 61 to move toward the inner wall of the damaged casing until the template 61 is tightly attached to the inner wall of the damaged casing to close the reaming. After the template 61 is attached, the grouting mechanism 7 injects cement slurry into the reaming hole through the grouting hole on the template 61. After the cement slurry solidifies, the mold-attaching driving cylinder 624 reverses and pulls the second slider 622 to separate the template 61 from the inner wall of the damaged casing, preparing for the next detection and repair operation.

[0081] In one embodiment, see Figure 1-Figure 4, a closed slurry chamber 12 is also formed in the sleeve 1, and the slurry chamber 12 is used to store cement slurry (injected before going down the well); the grouting mechanism 7 includes a grouting pump 71 and a grouting pipe 72, the inlet of the grouting pump 71 is connected to the slurry chamber 12, and the outlet of the grouting pump 71 is connected to the grouting hole. In this embodiment, a closed slurry chamber 12 is provided in the sleeve 1 for pre-storing cement slurry, which provides an independent slurry storage space for grouting operations. Cement slurry is injected before going down the well, so that the repair device can directly perform grouting operations after going down the well, without the need for additional ground grouting equipment to supply cement slurry in real time, reducing the connection and deployment links between equipment, and improving the independence and convenience of the operation. The grouting mechanism 7 connects the slurry chamber 12 with the grouting holes on the template 61 through the grouting pump 71 and the grouting pipe 72, forming an efficient grouting channel. The grouting pump 71 can accurately control the delivery pressure and flow rate of the cement slurry, ensuring that the cement slurry is smoothly and evenly injected from the grouting hole into the expanded hole through the grouting pipe 72, thereby improving the efficiency and accuracy of grouting.

[0082] In one embodiment, see Figure 1 and Figure 2 The damaged casing repair device further comprises a protective plate 13, which is arranged protruding from the sleeve 1. The protective plate 13 can protect the structures such as the hole expansion mechanism 5, the mold sticking mechanism 6 and the grouting mechanism 7.

[0083] The present invention also provides a method for repairing downhole casing damage, which is applicable to the device for repairing downhole casing damage, and comprises the following steps:

[0084] (1) Installation and lowering of the device: The damaged casing repair device is installed at the lower end of the coiled tubing 8, and the entire device is driven to move downward in the damaged casing 9 by the coiled tubing 8.

[0085] (2) Centering and positioning: During the downward movement of the device, the centering mechanism 3 plays a role in positioning the device at the center of the damaged casing to ensure the accuracy of subsequent operations. At the same time, the positioning mechanism 4 continuously detects the damaged casing. When the positioning mechanism 4 detects the damaged area, it immediately positions the damaged area.

[0086] (3) Azimuth adjustment and hole enlargement: Based on the positioning result of the positioning mechanism 4, the rotating mechanism 2 starts to work and drives the sleeve 1 to rotate, so that the positions of the hole enlargement mechanism 5, the mold sticking mechanism 6 and the grouting mechanism 7 are consistent with the position of the damaged area. Then, according to the position information determined by the positioning, the coiled tubing 8 is lowered to a specific length, so that the hole enlargement mechanism 5 is first accurately aligned with the damaged area, and then the hole enlargement mechanism 5 performs hole enlargement operation on the damaged area of ​​the damaged casing 9 and the cement ring 91 outside the damaged casing, thereby forming an enlarged hole.

[0087] (4) Forming and grouting: After the hole is expanded, the coiled tubing 8 is lowered again to a specific length so that the forming mechanism 6 is aligned with the damaged area, and the forming drive 62 drives the template 61 to fit and close the expanded hole. After that, the coiled tubing 8 is lowered again to a specific length so that the grouting mechanism 7 is aligned with the damaged area, and cement slurry is injected into the expanded hole.

[0088] (5) Subsequent operation: After the cement slurry solidifies, the mold sticking mechanism 6 releases the mold plate 61, and the device continues to move downward through the continuous oil pipe 8 to perform the next inspection and repair operation of the damaged area.

[0089] The beneficial effects of the technical solution provided by the present invention include:

[0090] (1) Enhanced bonding strength and pressure bearing capacity: The damaged area is expanded by the expansion mechanism 5, which not only removes the corrosion structure, but also increases the contact area and flatness of the contact between the damaged area and the cement slurry. Compared with the traditional method where the rupture and leakage are not pretreated, the cement slurry can be more firmly combined with the damaged part, effectively improving the pressure bearing capacity of the casing after repair, solving the problem of low pressure bearing capacity in the traditional repair method, reducing the risk of casing damage again due to insufficient pressure bearing, and ensuring the stability of oilfield production operations.

[0091] (2) Avoiding the reduction of effective aperture: This technical solution does not require drilling a suspended plug like the traditional method, thus avoiding the problem of the effective aperture of the casing being reduced due to the borehole diameter being smaller than the inner diameter of the casing. This ensures that subsequent operations such as string running can proceed smoothly without being hindered by the reduction of the aperture, ensuring the smoothness of the mining operation process and improving the operation efficiency.

[0092] (3) Ensure the structural strength and sealing effect of the cement plug: Since the suspended plug is not drilled, the cement plug structure will not be damaged, thereby ensuring the structural strength of the cement plug and improving its sealing effect. This helps to better seal the damaged parts and prevent problems such as water, sand, and blowout in the oil well, improve the quality of repair, extend the service life of the oil well, reduce the possibility of oil well scrapping due to poor repair quality, and reduce resource and economic losses.

[0093] The specific implementation of the present invention described above does not constitute a limitation on the protection scope of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A device for repairing downhole casing damage, characterized in that: include: A sleeve, the sleeve being used for rotationally connecting to one end of the coiled tubing; a rotating mechanism, the rotating mechanism being connected to both the sleeve and the coiled tubing and being used for driving the sleeve to rotate relative to the coiled tubing; A centering mechanism, which is mounted on the sleeve and is used to center the sleeve at the damaged sleeve; A positioning mechanism, the positioning mechanism is mounted on the sleeve and is used to position the damaged area of ​​the damaged sleeve; A hole expansion mechanism, which is installed on the sleeve and is used to expand the damaged area of ​​the damaged casing to form an expanded hole in the damaged casing and in the cement ring outside the damaged casing; A die sticking mechanism, the die sticking mechanism comprising a template and a die sticking driving member, the die sticking driving member being connected to the template and used to drive the template to stick and close the expanded hole; and A grouting mechanism is used to inject cement slurry into the expanded hole.

2. The device for repairing downhole casing damage according to claim 1, characterized in that: The sleeve is used to be connected to one end of the coiled tubing via a rotary joint, the fixed end of the rotary joint is fixedly connected to the coiled tubing, and the rotating end of the rotary joint is fixedly connected to the sleeve; The rotating mechanism includes a sleeve, a fixed ring, a gear ring, a rotating motor and a gear. The sleeve is sleeved on the coiled tubing and fixedly connected to the fixed end of the rotating joint. The fixed ring is fixedly sleeved on the sleeve. The gear ring is fixed to the fixed ring. The fixed end of the rotating motor is fixed to the sleeve. The output end of the rotating motor is coaxially fixedly connected to the gear, and the gear is meshed with the gear ring.

3. The device for repairing downhole casing damage according to claim 1, characterized in that: The centering mechanism includes a plurality of supporting members, each of which includes a swing arm, a roller, a cylinder and an air pump. One end of the swing arm is hinged to the outer wall of the sleeve, the roller is installed on the other end of the swing arm, the fixed end of the cylinder is hinged to the outer wall of the sleeve, the output end of the cylinder is hinged to the swing arm, and the outlet of the air pump is connected to the air inlet of the cylinder.

4. The device for repairing downhole casing damage according to claim 1, characterized in that: The positioning mechanism includes a plurality of cameras, a plurality of fill-light components and an image processor. Each of the cameras is mounted on the outer wall of the sleeve. Each of the fill-light components is used to fill-light the corresponding camera. The image processor is electrically connected to each of the cameras and is used to obtain the depth and orientation of the damaged area of ​​the damaged sleeve based on the images taken by each of the cameras.

5. The device for repairing downhole casing damage according to claim 1, characterized in that: The reaming mechanism includes a first fixed plate, a first slider, a reaming motor, a reaming drill bit and a reaming pushing cylinder. The first fixed plate is fixed in the sleeve, the first slider is slidably arranged on the first fixed plate, the fixed end of the reaming motor is fixed to the first slider, the reaming drill bit is fixed to the output end of the reaming motor, the fixed end of the reaming pushing cylinder is fixed to the sleeve, and the movable end of the reaming pushing cylinder is connected to the fixed end of the reaming motor and is used to drive the fixed end of the reaming motor to move.

6. The device for repairing downhole casing damage according to claim 5, characterized in that: A closed water passage cavity is formed in the sleeve, and the rotary joint is connected to the water passage cavity; The reaming mechanism also includes a spray assembly, which includes a spray head, a connecting pipe and a valve body. The spray head is fixed to the sleeve, and the outlet of the spray head is arranged laterally and not above the reaming drill bit. One end of the connecting pipe is connected to the water chamber, and the other end of the connecting pipe is connected to the water inlet end of the spray head. The valve body is arranged on the connecting pipe.

7. The device for repairing downhole casing damage according to claim 1, characterized in that: The template is arc-shaped and can be attached to the inner wall of the damaged casing. A grouting hole and an exhaust hole are provided on the template. The grouting mechanism is used to inject cement slurry into the expanded hole through the grouting hole.

8. The device for repairing downhole casing damage according to claim 7, characterized in that: The mold driving component includes a second fixed plate, a second slider, a pushing rod and a mold driving cylinder. The second fixed plate is fixed in the sleeve, the second slider is slidably arranged on the second fixed plate, one end of the pushing rod is fixed to the second slider, the other end of the pushing rod is fixed to the template, the fixed end of the mold driving cylinder is fixed to the sleeve, and the output end of the mold driving cylinder is fixedly connected to the second slider.

9. The device for repairing downhole casing damage according to claim 7, characterized in that: A closed slurry cavity is also formed in the sleeve; The grouting mechanism comprises a grouting pump and a grouting pipe, the inlet of the grouting pump is communicated with the slurry cavity, and the outlet of the grouting pump is communicated with the grouting hole.

10. A method for repairing downhole casing damage, characterized in that: The device for repairing downhole casing damage is applicable to any one of claims 1 to 9, and comprises the following steps: Device installation and lowering: Install the damaged casing repair device at the lower end of the coiled tubing, and use the coiled tubing to drive the entire device to move downward in the damaged casing; Centering and positioning: During the downward movement of the device, the centering mechanism plays a role in placing the device at the center of the damaged casing to ensure the accuracy of subsequent operations. At the same time, the positioning mechanism continuously detects the damaged casing. When the positioning mechanism detects the damaged area, it immediately locates the damaged area. Azimuth adjustment and hole expansion: According to the positioning result of the positioning mechanism, the rotating mechanism starts to work and drives the sleeve to rotate, so that the position of the hole expansion mechanism, the mold sticking mechanism and the grouting mechanism is consistent with the position of the damaged area. Then, according to the position information determined by the positioning, the coiled tubing is lowered to a specific length, so that the hole expansion mechanism is first accurately aligned with the damaged area, and then the hole expansion mechanism expands the damaged area of ​​the damaged casing and the cement ring outside the damaged casing to form an expanded hole; Formwork and grouting: After the hole expansion is completed, the coiled tubing is lowered again to a specific length so that the formwork mechanism is aligned with the damaged area, and the formwork drive drives the template to fit and close the hole expansion. After that, the coiled tubing is lowered again to a specific length so that the grouting mechanism is aligned with the damaged area, and cement slurry is injected into the hole expansion; Subsequent operations: After the cement slurry solidifies, the mold-sticking mechanism releases the template, and the device continues to move downward through the continuous oil pipe to carry out the next inspection and repair operation of the damaged area.

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