A casing wiper tool and method

Abstract

The present application belongs to the technical field of downhole key tools for oil and gas drilling and fracturing, and particularly relates to a casing temporary sealing tool and a temporary sealing method. The casing temporary sealing tool is used for plugging inside a casing string, and comprises a tool mandrel, a center shaft, a sealing structure, a push block, a locking rod, a connecting shaft, a clamping arm structure, a releasing sub and a gapless ring. The center shaft is pushed, and the sawtooth-shaped protrusions on the outer surface of the push block form a first-stage positioning with the casing string, and the sealing structure forms a seal with the casing string. The outer surface of the connecting shaft is provided with the clamping arm structure, and the clamping arm structure cooperates with a groove arranged in the casing string to realize second-stage positioning. The structure of the present application can realize sealing of the casing through cooperation of the sealing structure, the push block and the clamping arm structure. Through the push block and the clamping arm structure, twice positioning and setting are realized, the temporary sealing tool is prevented from slipping and moving, and better setting effect is achieved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of downhole key tools for oil and gas drilling and fracturing, and particularly relates to a casing temporary sealing tool and a temporary sealing method. BACKGROUND

[0002] With the in-depth development of unconventional oil and gas resources, especially shale oil and gas, tight oil and gas, and low-permeability oil and gas, in order to improve the initial production and ultimate recovery, separate layer injection and production and multi-stage staged fracturing have become one of the effective means for efficient development of unconventional oil and gas resources. During the staged fracturing construction process, the casing temporary sealing tool is lowered and set at a predetermined position in the wellbore and is set, so as to realize the staged isolation of the casing at the well bottom and ensure the effective construction of the staged fracturing of the oil and gas well. Therefore, the casing temporary sealing tool is a necessary tool for realizing the multi-stage staged fracturing. After the fracturing construction is completed, the casing temporary sealing tool body can be completely dissolved by relying on the temperature and the mineralized liquid environment of the wellbore, so as to ensure the rapid recovery of the full gauge production of the wellbore, and is widely used at home and abroad.

[0003] For example, a full-metal dissolvable fracturing segmenter is disclosed in Chinese Patent CN112576231B. The anchoring system of the fracturing segmenter is to set a continuous concave-convex wave shape on the outer wall of the integral slip and make the slip by spraying, surfacing, and particle bonding. Other common slip components are to embed hard alloy or high-molecular ceramic supported anchoring teeth on the outer circle of the slip. When the downhole setting tool applies an axial force, the high-strength anchoring teeth of the slip expand outward and bite into the inner wall of the casing, so as to realize the anchoring of the temporary plugging tool. The sealing assembly is extruded and deformed to tightly contact the casing wall and is locked, so as to realize the sealing and interlayer isolation of the downhole casing.

[0004] However, due to the complex working conditions in the downhole casing or the deformation of the casing, the expansion of the slips is inconsistent, the anchoring is uneven, or the anchoring teeth of the slip bite into the casing to different depths or insufficient depth, and the like, so that the temporary plugging tool slips and moves after setting during the construction process, resulting in setting failure and affecting the fracturing construction. Meanwhile, the anchoring teeth cannot be dissolved in the downhole, and a large number of anchoring teeth are embedded in the casing arm or accumulated in the casing, which increases the complexity and risk of subsequent construction and flowback. When the anchoring teeth bite into the inner wall of the casing to a certain depth, the local strength of the inner wall of the casing is reduced, and the risk of casing deformation is increased.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] In order to solve the technical problems existing in the prior art, the present application provides a casing temporary sealing tool and a temporary sealing method, the structure of the present application can realize the sealing of the casing through the cooperation of the sealing structure, the push block, the clamping arm structure and other structures; the twice positioning and setting of the push block and the clamping arm structure can avoid the sliding and movement of the temporary sealing tool, and has better setting effect.

[0007] The present application comprises the following technical solutions:

[0008] The present application provides a casing temporary sealing tool for internal plugging of a casing string, which comprises a tool mandrel, a central shaft, a sealing structure, a push block, a locking rod, a connecting shaft, a clamping arm structure, a releasing sub and a gapless ring.

[0009] The end of the tool mandrel is provided with a releasing sub; the connecting shaft, the locking rod and the central shaft are sequentially arranged outside the tool mandrel, extending away from the end of the releasing sub; the releasing sub limits one end of the connecting shaft, the other end of the connecting shaft cooperates with one end of the locking rod, and the connecting shaft is provided with a boss cooperating with the push block, and the other end of the locking rod cooperates with the central shaft.

[0010] The sealing structure, the gapless ring and the push block are sequentially arranged outside the central shaft and / or the locking rod.

[0011] The inner surfaces of the sealing structure, the gapless ring and the push block are arranged as inner taper shapes, and the outer surface of the central shaft is arranged as an outer taper shape; and the taper degrees of the inner taper shape and the outer taper shape are consistent.

[0012] The central shaft is pushed, the outer taper shape moves relative to the inner taper shape, the central shaft extrudes the sealing structure, the gapless ring and the push block to expand, the serrated protrusions on the outer surface of the push block form a first level positioning with the casing string, and the sealing structure forms a seal with the casing string.

[0013] The clamping arm structure is arranged on the outer surface of the connecting shaft, and the clamping arm structure is further arranged inside the casing string; the clamping arm structure comprises a first clamping arm, a second clamping arm, a sliding ring, a tail ring, a compression spring, a first anti-loosening ring and a second anti-loosening ring; the tail ring is connected to the connecting shaft through the first anti-loosening ring, and the sliding ring is connected to the connecting shaft through the second anti-loosening ring; one end of the tail ring is clamped to the releasing sub, and there is a space of movement between the connecting shaft and the releasing sub, the other end of the tail ring cooperates with one end of the sliding ring, the other end of the sliding ring rotatably connects one end of the first clamping arm, the other end of the first clamping arm connects one end of the second clamping arm, and the other end of the second clamping arm rotatably connects the boss; the compression spring is arranged between the tail ring and the sliding ring.

[0014] Further, the outer sawtooth thread of the first lock ring is matched with the inner sawtooth thread of the tail ring, and the inner sawtooth thread of the first lock ring is matched with the sawtooth thread of the connecting shaft; and / or the outer sawtooth thread of the second lock ring is matched with the inner sawtooth thread of the sliding ring, and the inner sawtooth thread of the second lock ring is matched with the sawtooth thread of the connecting shaft.

[0015] Further, the sealing structure comprises a protection ring and a rubber ring arranged in sequence, the push block is matched with the gapless ring, the gapless ring is matched with the rubber ring, and the rubber ring is matched with the protection ring.

[0016] Further, the gapless ring sleeve comprises a plurality of Z-shaped arc segments which are connected to each other in an overlapping manner.

[0017] Further, the protection ring is matched with the rubber ring through a slope, and the inclination direction of the slope is the same as the inclination direction of the outer surface of the central shaft; and the rubber ring is matched through a chamfer.

[0018] Further, the rubber ring is formed by soluble rubber pressing, and the central shaft, the sealing structure, the push block, the locking rod, the connecting shaft, the clamping arm structure, the release joint and the gapless ring are all made of soluble metal.

[0019] Further, the push block comprises a fastening ring and a plurality of fastening blocks, the plurality of fastening blocks are arranged around the outer surface of the locking rod, and the plurality of fastening blocks are fixed into a circular ring shape through the fastening ring.

[0020] The second aspect of the present application provides a casing temporary sealing method comprising the temporary sealing tool, and the temporary sealing method comprises the following steps:

[0021] The temporary sealing tool is lowered into the casing string and located in the upper casing above the groove through the movement of the moving sleeve and the tool mandrel;

[0022] The tool mandrel is kept stationary, the moving sleeve is pushed to move downward, the central shaft slides downward under the action of the moving sleeve, the sealing structure and the gapless ring are gradually deformed to abut and seal against the inner wall of the casing under the joint action of the push block and the central shaft, and the sawtooth-shaped protrusions on the outer surface of the push block form the first level positioning with the casing under the action of the central shaft;

[0023] The moving sleeve is continuously pushed until the clamping arm structure is attached to the inner wall of the casing string; the moving sleeve is continuously pushed, the release thread is sheared, the moving sleeve and the tool mandrel are separated from the temporary sealing tool under the driving of the downhole tool, and the release joint is separated from the temporary sealing tool;

[0024] The pressure ball is matched with the center shaft, when the pressure at the upper end of the temporary sealing tool is greater than the pressure below, the temporary sealing tool is not completely positioned and gradually slides downward until the sliding to the groove of the casing string, the clamping arm structure abuts against the groove of the casing string to form the second positioning.

[0025] Further, the temporary sealing tool is sealed and positioned, and the steps of releasing the sealing and positioning are further included: after the fracturing operation is completed, the temporary sealing tool is dissolved under the specific temperature and salinity conditions in the well to release the sealing and positioning, and the drift diameter of the casing string is restored.

[0026] By adopting the technical scheme, the present application has the following advantages:

[0027] 1. The structure of the present application can realize the sealing of the casing through the cooperation of the sealing structure, the push block and the clamping arm structure; the two positioning and setting are realized through the push block and the clamping arm structure, the temporary sealing tool is prevented from slipping and moving, and better setting effect is achieved.

[0028] 2. The present application has the effect of separating the setting and positioning, the push block is pushed by the connecting shaft on the setting side, the gapless ring, the rubber ring and the protection ring are further moved forward along the taper surface of the center shaft and expanded outward at the same time, when the protection ring stops moving forward, the rubber ring is further expanded outward under the support of the protection ring, the gap between the center shaft and the inner wall of the casing is fully filled, and a certain pressure is borne. Since the connecting shaft and the center shaft are connected together by the locking rod, the position of the push block relative to the rubber ring is locked, so that the sealing is formed, the outer circle of the push block is provided with a sawtooth-shaped protrusion, a certain friction force is formed between the push block and the inner wall of the casing after setting, and the effect of preliminary setting and positioning (the first positioning) is achieved. The pin is arranged between the hanging clamping arm on the positioning side, the connecting shaft and the sliding ring, which can ensure that the temporary sealing tool is set and fractured according to the plan; the second anti-loose ring is arranged between the sliding ring and the connecting shaft, which can prevent the right hanging clamping arm from moving reversely driven by the sliding ring, and ensure the positioning to be firm; the temporary sealing tool can always maintain the sealing state during the process of running downward to the casing coupling position under the upper pressure, and the hanging clamping positioning (the second positioning) can be rapidly realized after reaching the concave space.

[0029] 3. On the basis of the preliminary setting and positioning, the clamping arm positioning is increased through the compression spring compression rebound, the sawtooth-shaped thread reverse locking protection function of the anti-loose ring and other functions, the setting stability of the temporary sealing tool during the fracturing process is realized, the pressure bearing is reliable, the hanging clamping positioning is convenient, and the smooth operation of the construction process is ensured.

[0030] 4. The clamping arm structure and the concave space on the casing string are matched to realize the hanging clamping positioning of the temporary sealing tool, and the problems of the temporary sealing tool slipping and anchoring failure caused by the unfirm anchoring of the conventional temporary sealing tool clamping jaw anchor are effectively avoided.

[0031] 5. The temporary sealing tool of this invention leaves no residue after dissolution, eliminating the need for continuous tubing drilling and plugging operations after fracturing. This effectively solves the problem of segmented fracturing stimulation in ultra-long horizontal wells and complex well conditions. It allows for differentiated design of matching specifications, dimensions, and performance indicators for different casing and wellbore conditions, controlling sealing pressure and dissolution time to ensure successful operation under various conditions, thus forming a dedicated design method and operational process.

[0032] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention can be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the structure of a cannula temporary sealing tool according to an embodiment of the present invention;

[0035] Figure 2 This is a schematic diagram of the initial state structure of the gapless ring in an embodiment of the present invention;

[0036] Figure 3 This is a schematic diagram of the structure after the gapless ring is expanded in an embodiment of the present invention;

[0037] Figure 4 This is a schematic diagram of the structure of a sleeve temporary sealing tool after sealing and first positioning in an embodiment of the present invention;

[0038] Figure 5 This is a schematic diagram of the structure of a casing temporary sealing tool after sealing and setting in an embodiment of the present invention;

[0039] In the diagram: 10-Tool spindle, 20-Central shaft, 30-Sealing structure, 31-Protective ring, 32-Glue ring, 321-Deformation space, 40-Gapless ring, 50-Push block, 51-Fastening ring, 52-Fastening block, 60-Locking rod, 70-Connecting shaft, 71-Boss, 80-Clamping arm structure, 81-First clamping arm, 82-Second clamping arm, 83-Sliding ring, 84-Tail ring, 85-Compression spring, 86-First anti-loosening ring, 87-Second anti-loosening ring, 90-Hand release connector, 100-Sleeve column, 101-Groove, 110-Moving sleeve, 120-Pressure ball. Detailed Implementation

[0040] The following description provides many different embodiments or examples for implementing various features of the invention. The elements and arrangements described in the specific examples below are only for concise expression of the invention and are merely examples, not intended to limit the invention.

[0041] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] This embodiment provides a casing temporary sealing tool for sealing the inside of the casing string 100, such as... Figure 1 As shown, the temporary sealing tool includes: a tool spindle 10, a central shaft 20, a sealing structure 30, a push block 50, a locking rod 60, a connecting shaft 70, a clamping arm structure 80, a release connector 90, and a gapless ring 40.

[0043] The tool spindle 10 has a release connector 90 at one end; extending from the release connector 90 away from the end, a connecting shaft 70, a locking rod 60, and a central shaft 20 are sequentially arranged outside the tool spindle 10; the release connector 90 limits one end of the connecting shaft 70, the other end of the connecting shaft 70 engages with one end of the locking rod 60, and the connecting shaft 70 has a boss 71 that engages with the push block 50; the other end of the locking rod 60 engages with one end of the central shaft 20, and the other end of the locking rod 60 engages with the connecting shaft 70;

[0044] A sealing structure 30, a gapless ring 40, and a push block 50 are sequentially arranged outside the central shaft 20 and / or the locking rod 60. In the initial state of the temporary sealing tool, the positions of the sealing structure 30, the gapless ring 40, and the push block 50 are not limited. It is only necessary to ensure that after the central shaft 20 is pushed, the sealing structure 30, the sealing ring, and the push block 50 can cooperate with the central shaft 20 to achieve sealing and positioning.

[0045] The inner surfaces of the sealing structure 30, the gapless ring 40, and the push block 50 are set as inner cones, and the outer surface of the central shaft 20 is set as an outer cone; and the tapers of the inner and outer cones are the same; this makes the sealing structure 30, the gapless ring 40, and the push block 50 fit more tightly with the central shaft 20, improving the sealing and positioning effect;

[0046] Push the center shaft 20, the outer cone and the inner cone opposite movement, the center shaft 20 extrusion seal structure 30, no gap ring 40 and push block 50 expansion, the push block 50 of the outer surface of the sawtooth-shaped protrusions and casing string 100 form the first level positioning, the sealing structure 30 and casing string 100 form a seal;

[0047] The outer surface of the connecting shaft 70 is provided with the card arm structure 80, which cooperates with the groove 101 provided in the casing string 100 to realize the second level positioning.

[0048] Wherein, as Figure 1 The end of the center shaft 20 is provided with a step for cooperating with the moving sleeve 110, and the moving sleeve 110 is used to drive the center shaft 20 to move when the temporary sealing tool of the application is used for temporary sealing of the casing string 100.

[0049] The tool mandrel 10 is a solid shaft structure, as Figure 1 The tool mandrel 10 is a solid shaft structure, as

[0050] The release sub 90 is also a ring structure, the center is a release thread, the right side is a stepped hole, and two pin holes are provided on the circumference of the right side stepped hole. The outer surface of the release sub 90 is a conical surface structure, which can play a guiding role during the downhole process.

[0051] Preferably, as Figure 1 The center shaft 20 is provided with an inner taper, which is used to cooperate with the outer taper provided on the working mandrel; the inner taper of the center shaft 20 can also cooperate with the pressure ball 120 when the pressure ball 120 is put into the well; and the pressure of the pressure ball 120 can be better received.

[0052] In some embodiments, the locking arm structure 80 includes a first locking arm 81, a second locking arm 82, a sliding ring 83, a tail ring 84, a compression spring 85, a first anti-loosening ring 86, and a second anti-loosening ring 87. The tail ring 84 is connected to the connecting shaft 70 through the first anti-loosening ring 86, and the sliding ring 83 is connected to the connecting shaft 70 through the second anti-loosening ring 87. One end of the tail ring 84 is engaged with the release connector 90. For example, the lower end of the tail ring 84 is machined with several first protrusions, and the upper end of the release connector 90 is machined with several first grooves that connect and cooperate with the first protrusions. This allows for a space of movement between the connecting shaft 70 and the release connector 90. The other end of the tail ring 84 is engaged with one end of the sliding ring 83. The other end of the sliding ring 83 is rotatably connected to one end of the first locking arm 81. The other end of the first locking arm 81 is connected to one end of the second locking arm 82, and the other end of the second locking arm 82 is rotatably connected to the protrusion 71. The compression spring 85 is disposed between the tail ring 84 and the sliding ring 83.

[0053] like Figure 1 As shown, the mating surface between the boss 71 on the connecting shaft 70 and the push block 50 is inclined, so that the force on the push block 50 can be applied more evenly and effectively to the boss 71; as Figure 1 The inclination direction of the mating surface is towards the boss 71, which further improves the uniformity and effectiveness of the force distribution.

[0054] The first locking arm 81 is connected to the sliding ring 83 by a pin and a pin. In the initial state, the first locking arm 81 and the sliding ring 83 are fixed by the pin. The pin is sheared after being subjected to force, so that the first locking arm 81 can rotate relative to the sliding ring 83. Similarly, the first locking arm 81 is also connected to the second locking arm 82 by a pin and a pin, and the second locking arm 82 is also connected to the boss 71 by a pin and a pin.

[0055] The boss 71 is provided with a second connecting groove for connecting with the second locking arm 82. Multiple second connecting grooves are provided and are evenly arranged around the boss 71. Correspondingly, multiple second locking arms 82 are also provided. The sliding ring 83 is also provided with a first connecting groove for connecting with the first locking arm 81. Multiple second connecting grooves are provided and are evenly arranged around the boss 71. This structure allows the first locking arm 81 and the second locking arm 82 to act evenly around the groove 101 of the sleeve post 100, resulting in a better positioning effect.

[0056] The sliding ring 83 is also provided with a spring connecting groove for connecting the compression spring 85. The number of connecting grooves is determined according to the number of compression springs 85. The number of compression springs 85 is set to 4-12 according to their elasticity. In this embodiment, the number is 8.

[0057] As shown in Figure 1 The outer circle right side of the tail ring 84 is a conical surface structure, which plays a guiding role in the process of temporarily sealing tool downhole; at the same time, the conical surface structure and the conical surface structure of the release sub 90 outer surface are smoothly overlapped, which plays a better guiding role; the tail ring 84 is located on the left side of the tail ring 84, which is provided with an inner stepped hole, and the slip ring 83 is located on the right side of the slip ring 83, which is provided with an outer step, the inner stepped hole and the outer step cooperate, and the inner stepped hole and the outer step cooperate, which can play a guiding role when the slip ring 83 moves. The spring connecting groove is arranged on the outer step.

[0058] As shown in Figure 5 When the compression spring 85 rebounds, it pushes the slip ring 83 and the clamping arm (the first clamping arm 81 and the second clamping arm 82) to act until it is hung and clamped into the groove 101, and the slip ring 83 itself must be axially sliding in the stepped hole of the tail ring 84 without disengaging. Such structure makes the positioning of the first clamping arm 81 and the second clamping arm 82 more stable, and has better positioning effect.

[0059] Specifically, the first clamping arm 81 and the second clamping arm 82 are initially in contact with the inner wall of the casing when they are spread, and when the temporary sealing tool moves down, the first clamping arm 81 and the second clamping arm 82 are clamped into the groove 101 of the casing string 100 by the action force generated by the rebound of the compression spring 85, which requires an axial stroke of the slip ring 83.

[0060] 1. The compression amount of the compression spring 85 is greater than the axial stroke of the slip ring 83, which ensures that the first clamping arm 81 and the second clamping arm 82 can be pushed into place, and here is the length of the compression spring 85 rebound.

[0061] 2. The depth of the stepped hole on the left side of the tail ring 84 should be greater than the length of the compression spring 85 rebound, that is, the compression spring 85 cannot make the slip ring 83 disengage from the stepped hole of the tail ring 84 when it rebounds, so as to avoid the tail ring 84 losing the positioning and guiding effect on the slip ring 83; at the same time, the positioning effect of the first clamping arm 81 and the second clamping arm 82 is improved.

[0062] In some embodiments, the outer sawtooth thread of the first locking ring 86 and the inner sawtooth thread of the tail ring 84 cooperate, the inner sawtooth thread of the first locking ring 86 cooperates with the sawtooth thread of the connecting shaft 70; and / or the outer sawtooth thread of the second locking ring 87 and the inner sawtooth thread of the slip ring 83 cooperate, the inner sawtooth thread of the second locking ring 87 cooperates with the sawtooth thread of the connecting shaft 70.

[0063] Preferably, the outer zigzag thread pitch of the first anti-loosening ring 86 is greater than the inner zigzag thread pitch thereof; the outer zigzag thread pitch of the second anti-loosening ring 87 is greater than the inner zigzag thread pitch thereof; this is more conducive to the shearing of the pin connecting the first clamping arm 81 and the second clamping arm 82, the pin connecting the first clamping arm 81 and the sliding ring 83, and the pin connecting the second clamping arm 82 and the boss 71, and has the advantage of improving the positioning efficiency.

[0064] Preferably, the first anti-loosening ring 86 and the second anti-loosening ring 87 are annular structures with notches, have a certain elastic deformation of contraction / expansion, and have a certain elastic deformation capacity of contraction / expansion, so as to ensure that the sliding ring 83 and the tail ring 84 can be self-locked after being slid on the outer circle of the connecting shaft 70, thereby preventing rebound.

[0065] In some embodiments, the sealing structure 30 comprises, in sequence, a protection ring 31, a rubber ring 32, and a gapless ring 40, the push block 50 is matched with the gapless ring 40, the gapless ring 40 is matched with the rubber ring 32, and the rubber ring 32 is matched with the protection ring 31.

[0066] As shown in Figure 1 , the cross section of the protection ring 31 is a triangular structure, which can ensure that the rubber ring 32 is always supported by the protection ring 31 when being pushed upward and stretched; the height of the protection ring 31 is higher than the distance between the center shaft 20 and the sleeve when the rubber ring 32 reaches the maximum position (i.e., when the protection ring 31 is deformed to the limit position), as shown in Figure 4 , Figure 5 , so as to support the front end of the rubber ring 32, and to withstand the pressure at the upper end under the premise of effective deformation of the rubber ring 32.

[0067] As shown in Figure 1 , the front end of the gapless ring 40 is matched with the chamfered portion of the rubber ring 32 to form a supporting effect on the rubber ring 32, and the rear end of the gapless ring 40 is a stepped hole matched with the step at the front end of the push block 50 to tightly clamp the push block 50, so that the push block 50 forms an integral whole.

[0068] In some embodiments, as shown in Figure 2 , which is a structure diagram of the initial state of the gapless ring 40, the gapless ring 40 comprises a plurality of Z-shaped arc segments, and the plurality of Z-shaped arc segments are connected to each other in an overlapping manner; as shown in Figure 3 , which is a structure diagram of the gapless ring 40 after being expanded and seated, the length of the overlap between the two gapless blocks needs to be greater than the gap between the push blocks 50 after being seated, so as to provide sufficient pressure support during the expansion of the rubber ring 32.

[0069] In some embodiments, the protective ring 31 and the rubber ring 32 are matched by a bevel, and the bevel has the same inclination direction as the outer surface of the central shaft 20; the rubber ring 32 is matched by a chamfer.

[0070] In some embodiments, the rubber ring 32 is made of soluble rubber, which can be expanded outwardly during the setting process to fill the space between the central shaft 20 and the casing string 100 to form a seal. The soluble rubber can be completely dissolved in a solution at a certain temperature. The central shaft 20, the sealing structure 30, the push block 50, the locking rod 60, the connecting shaft 70, the clamping arm structure 80, the releasing joint 90 and the gapless ring 40 are all made of soluble metal, which can be completely dissolved in a solution at a certain temperature. The soluble metal can be a soluble magnesium alloy, a soluble aluminum alloy, etc.

[0071] The tool mandrel 10 and the moving sleeve 110 are made of alloy steel, and the compression spring 85 is a commercially available product.

[0072] As shown in Figure 1 The front end and the rear end of the rubber ring 32 are provided with chamfers, and the middle part is provided with a deformation space 321. The chamfer can not only be matched with the gapless ring 40, but also provide a margin for deformation. The matching of the chamfer and the deformation space 321 enables the rubber ring 32 to better deform and fit the inner wall of the casing string 100.

[0073] In some embodiments, the push block 50 includes a fastening ring 51 and a plurality of fastening blocks 52, which are arranged around the outside of the locking rod 60 and fixed into a circular ring shape by the fastening ring 51.

[0074] As shown in Figure 1 The front end of the push block 50 has a step for matching the gapless ring 40. The outer circle is provided with a sawtooth structure, the size of which is slightly higher than the maximum outer circle. The middle rear end of the outer circle is provided with an annular groove, in which the fastening ring 51 is arranged. The front end of the inner hole is a conical surface structure, and the rear end of the conical surface is serrated.

[0075] In some embodiments, the outer serrated thread of the locking rod 60 is matched with the inner serrated thread of the inner hole of the central shaft 20. Preferably, the locking rod 60 is an annular structure with a notch, and the width (arc length) of the notch should be not less than 5% of the circumference of the outer serrated section.

[0076] The present embodiment also provides a casing temporary sealing method, which includes the temporary sealing tool described above, and the temporary sealing method includes the following steps:

[0077] The temporary sealing tool is lowered into the casing string 100 by the moving sleeve 110 and the tool mandrel 10 and located in the upper casing above the groove 101;

[0078] Keeping the tool mandrel 10 stationary, the moving sleeve 110 is pushed down, the central shaft 20 slides down under the action of the moving sleeve 110, the sealing structure 30 and the gapless ring 40 are gradually deformed to abut and seal with the inner wall of the casing under the joint action of the push block 50 and the central shaft 20, the sawtooth-shaped protrusions on the outer surface of the push block 50 form the first level positioning with the casing;

[0079] Continue to push the moving sleeve 110 until the clamping arm structure 80 abuts the inner wall of the casing string 100; continue to push the moving sleeve 110, the shear the release thread, the moving sleeve 110 and the tool mandrel 10 are separated from the temporary sealing tool under the driving of the downhole tool, and the release joint 90 is separated from the temporary sealing tool;

[0080] The pressure ball 120 is launched, and the pressure ball 120 cooperates with the central shaft 20; when the pressure at the upper end of the temporary sealing tool is greater than the pressure below, the temporary sealing tool will gradually slide down because it is not completely positioned, until it slides to the groove 101 of the casing string 100, the clamping arm structure 80 abuts the groove 101 of the casing string 100 to form the second level positioning.

[0081] In some embodiments, the temporary sealing method comprises:

[0082] The temporary sealing tool is lowered into the casing string 100 by the moving sleeve 110 and the tool mandrel 10 and located in the upper casing above the groove 101;

[0083] As shown in Figure 1 Keeping the tool mandrel 10 stationary, the moving sleeve 110 is pushed down, the central shaft 20 slides down under the action of the moving sleeve 110, the sealing structure 30 and the gapless ring 40 are gradually deformed to abut and seal with the inner wall of the casing under the joint action of the push block 50 and the central shaft 20, the sawtooth-shaped protrusions on the outer surface of the push block 50 form the first level positioning with the casing;

[0084] Continue to push the moving sleeve 110, the tail ring 84 moves, the release joint 90, the tail ring 84 pushes the second anti-loose ring 87, further pushes the slip ring 83 to move forward relative to the connecting shaft 70, the pin connecting the second clamping arm 82 and the connecting shaft 70 is sheared, the pin connecting the first clamping arm 81 and the slip ring 83 is sheared, the first clamping arm 81 and the second clamping arm 82 rotate, until the first clamping arm 81 and the second clamping arm 82 tightly abut the inner wall of the casing string 100 and cannot rotate any more, at this time the compression spring 85 is still in the compressed state; as shown in Figure 4As shown, continue to push the moving sleeve 110, due to the shear force of the release thread of the release joint 90 is less than the pushing force of the moving sleeve 110, the release thread is sheared, the moving sleeve 110 and the tool mandrel 10 are separated from the temporary plugging tool under the driving of the downhole tool; at the same time, the release joint 90 is separated from the temporary plugging tool;

[0085] As shown, the pressure ball 120 is put into the well, and the pressure ball 120 cooperates with the central shaft 20; when the pressure at the upper end of the temporary plugging tool is greater than the pressure at the lower end, the temporary plugging tool will gradually slide downward until it slides to the groove 101 of the casing string 100 because the temporary plugging tool is not completely positioned; the compression spring 85 pushes the sliding ring 83 and drives the second anti-loose ring 87 to move forward, and at the same time, the first clamping arm 81 is driven to rotate relatively, and the second clamping arm 82 is driven to rotate relatively until the first clamping arm 81 and the second clamping arm 82 abut against the groove 101 of the casing string 100 to form the second positioning. Figure 5 When the temporary plugging tool continues to run downward, the first clamping arm 81 and the second clamping arm 82 are in contact with the casing and are subjected to a downward pushing force, the sliding ring 83 generates a tendency to move backward, the sawtooth-shaped thread in the sliding ring 83 abuts against the sawtooth-shaped thread outside the second anti-loose ring 87, and the sawtooth-shaped thread inside the second anti-loose ring 87 abuts against the sawtooth-shaped thread outside the connecting shaft 70, so that the position of the sliding ring 83 is locked and cannot slide backward, and therefore the reverse rotation between the clamping arms is prevented, and the temporary plugging tool no longer runs downward, thereby achieving the effect of hanging and setting positioning.

[0086] In some embodiments, the step of releasing the sealing and positioning of the temporary plugging tool is further included: after the fracturing operation is completed, the temporary plugging tool is dissolved under the specific temperature and salinity conditions in the well to release the sealing and positioning, and the drift diameter of the casing string 100 is restored.

[0087] In the description of the present application, the terms "first", "second" are only used for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0088]

[0089] ​In the description of the present application, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "linking" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integral connection; can be mechanical connection, can also be electrical connection or can communicate with each other; can be directly connected, can also be indirectly connected through intermediate medium, can be internal communication of multiple elements or interaction relationship of multiple elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0090] In the description of the present application, it is necessary to understand that all the terms for indicating the position or position relationship are based on the position or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and cannot be understood as a limitation of the present application.

[0091] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A casing patch tool for plugging inside a casing string (100), characterized in that, The temporary sealing tool comprises a tool mandrel (10), a central shaft (20), a sealing structure (30), a push block (50), a locking rod (60), a connecting shaft (70), a clamping arm structure (80), a releasing joint (90) and a gapless ring (40); An end of the tool mandrel (10) is provided with the releasing joint (90), and a connecting shaft (70), a locking rod (60) and a central shaft (20) are sequentially arranged outside the tool mandrel (10) from the end of the releasing joint (90) away from the end of the releasing joint (90); the releasing joint (90) limits one end of the connecting shaft (70), the other end of the connecting shaft (70) is matched with one end of the locking rod (60), and the connecting shaft (70) is provided with a boss (71) matched with the push block (50), and the other end of the locking rod (60) is matched with the central shaft (20); The sealing structure (30), the gapless ring (40) and the push block (50) are sequentially matched and arranged outside the central shaft (20) and / or the locking rod (60); Inner surfaces of the sealing structure (30), the gapless ring (40) and the push block (50) are provided with inner taper shapes, and an outer surface of the central shaft (20) is provided with an outer taper shape; the taper degrees of the inner taper shape and the outer taper shape are consistent; The central shaft (20) is pushed, the outer taper shape moves relative to the inner taper shape, the central shaft (20) extrudes the sealing structure (30), the gapless ring (40) and the push block (50) to expand, and the outer surface of the push block (50) is provided with a sawtooth-shaped protrusion to form a first-stage positioning with the casing column (100), and the sealing structure (30) forms a seal with the casing column (100); An outer surface of the connecting shaft (70) is provided with the clamping arm structure (80), and the clamping arm structure (80) is matched with a groove (101) arranged in the casing column (100) to realize second-stage positioning; The sealing structure (30) comprises a protection ring (31) and a rubber ring (32) sequentially arranged, the push block (50) is matched with the gapless ring (40), the gapless ring (40) is matched with the rubber ring (32), and the rubber ring (32) is matched with the protection ring (31); The gapless ring (40) comprises a plurality of Z-shaped arc segments which are connected to each other in an overlapping manner.

2. A casing packoff tool as defined in claim 1, wherein, The clamping arm structure (80) comprises a first clamping arm (81), a second clamping arm (82), a sliding ring (83), a tail ring (84), a compression spring (85), a first anti-loosening ring (86) and a second anti-loosening ring (87), the tail ring (84) is connected with the connecting shaft (70) through the first anti-loosening ring (86), and the sliding ring (83) is connected with the connecting shaft (70) through the second anti-loosening ring (87); one end of the tail ring (84) is clamped with the release sub (90), and an activity space is formed between the connecting shaft (70) and the release sub (90), the other end of the tail ring (84) is matched with one end of the sliding ring (83), the other end of the sliding ring (83) is rotationally connected with one end of the first clamping arm (81), the other end of the first clamping arm (81) is connected with one end of the second clamping arm (82), and the other end of the second clamping arm (82) is rotationally connected with the boss (71); the compression spring (85) is arranged between the tail ring (84) and the sliding ring (83).

3. A casing packoff tool as defined in claim 2, wherein, The outer sawtooth thread of the first anti-loosening ring (86) is matched with the inner sawtooth thread of the tail ring (84), and the inner sawtooth thread of the first anti-loosening ring (86) is matched with the sawtooth thread of the connecting shaft (70); and / or the outer sawtooth thread of the second anti-loosening ring (87) is matched with the inner sawtooth thread of the sliding ring (83), and the inner sawtooth thread of the second anti-loosening ring (87) is matched with the sawtooth thread of the connecting shaft (70).

4. A casing packoff tool as defined in claim 1, wherein, The protection ring (31) is matched with the rubber ring (32) through a slope, and the inclination direction of the slope is the same as the inclination direction of the outer surface of the central shaft (20); the rubber ring (32) is matched through a chamfer.

5. A casing packoff tool as defined in claim 4, wherein, The rubber ring (32) is formed by soluble rubber pressing, and the central shaft (20), the sealing structure (30), the push block (50), the locking rod (60), the connecting shaft (70), the clamping arm structure (80), the release sub (90) and the gap-free ring (40) are all made of soluble metal.

6. A casing packoff tool as defined in claim 1, wherein, The push block (50) comprises a fastening ring (51) and a plurality of fastening blocks (52), the plurality of fastening blocks (52) are arranged outside the locking rod (60) in a ring shape, and the plurality of fastening blocks (52) are fixed into a circular ring shape through the fastening ring (51).

7. A casing packoff tool as defined in claim 1, wherein, The outer sawtooth thread of the locking rod (60) is matched with the inner sawtooth thread of the inner hole of the central shaft (20).

8. A method of temporary casing packoff, characterized by, The temporary sealing method comprises the temporary sealing tool as claimed in any one of claims 1-7, and the temporary sealing method comprises: lowering the temporary sealing tool into the casing string (100) and into an upper casing above the recess (101) through the moving sleeve (110) and the tool mandrel (10); Keep the tool mandrel (10) still, push the moving sleeve (110) to move downward, the central shaft (20) slides downward under the action of the moving sleeve (110), the sealing structure (30) and the gapless ring (40) gradually deform to abut and seal with the inner wall of the casing under the joint action of the push block (50) and the central shaft (20), the sawtooth-shaped protrusions on the outer surface of the push block (50) form the first level positioning with the casing under the action of the central shaft (20); Continue to push the moving sleeve (110) until the clamping arm structure (80) abuts the inner wall of the casing string (100); continue to push the moving sleeve (110), the shear the lost-hand thread, the moving sleeve (110) and the tool mandrel (10) are separated from the temporary sealing tool under the driving of the downhole tool, and the lost-hand joint (90) is separated from the temporary sealing tool; Put the pressure ball (120), the pressure ball (120) cooperates with the central shaft (20), when the pressure at the upper end of the temporary sealing tool is greater than the pressure below, the temporary sealing tool will gradually slide downward because it is not completely positioned, until it slides to the groove (101) of the casing string (100), the clamping arm structure (80) abuts the groove (101) of the casing string (100) to form the second level positioning.

9. A method of temporary casing seal according to claim 8, wherein, It also includes the steps of releasing the sealing and positioning of the temporary sealing tool: after the completion of the fracturing operation, the temporary sealing tool is dissolved under the conditions of specific temperature and salinity in the well to release the sealing and positioning, and restore the drift diameter of the casing string (100).

Images