Return-plugging connector

Abstract

The invention provides a back-inserting connector which comprises a pipe body with a step arranged on the outer surface, a setting cylinder arranged at the lower end of the pipe body in a sleeving mode and a packing rubber ring connected between the step and the upper end face of the setting cylinder in an abutting mode, and the setting cylinder is connected with the pipe body through a fixing part. The setting cylinder can cut off the fixing part and extrude the packing rubber ring together with the step through the upper end face of the setting cylinder after ascending, and the packing rubber ring expands and is tightly attached to the inner wall of the tie-back cylinder. The packer rubber ring can be extruded to be expanded and tightly attached to the inner wall of the tie-back barrel, so that secondary sealing of the plug-back connector and the inner wall of the tie-back barrel is achieved, and the fracturing quality is effectively improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of cementing tools, and specifically relates to a back-insertion joint. Background Art

[0002] In a conventional back-connection operation, a back-connection plug is usually used. The tube body of the conventional back-connection plug is embedded with a rubber sealing ring and is fitted with a metal fixing ring. After being inserted into the back-connection cylinder, it fits with the inner wall of the back-connection cylinder to play a sealing role. The specific operation process is as follows: Drill down to clear the cement plug above and inside the back-connection cylinder. After milling the back-connection cylinder, lower the casing string. Among them, the lowermost end of the casing string is connected to the back-connection plug. When the casing string is lowered in place, test-insert and adjust the length of the casing string, circulate for cementing, lower and insert the back-connection plug to seal the back-connection cylinder, and complete the hanging of the casing head. If the back-connection cylinder is worn by sweeping the plug or the sealing surface of the inner wall is damaged due to scraping, the sealing rubber ring of the back-connection plug cannot fit tightly with the inner wall of the back-connection cylinder after entering the back-connection cylinder, resulting in sealing failure and causing the load of pulling out the casing; after forced cementing, it is difficult to balance the pressure difference inside and outside the pipe, and the cement slurry flows back, reducing the cementing quality. Summary of the Invention

[0003] An object of the present invention is to provide a back-insertion joint, which can extrude the packer rubber ring to make it expand and tightly adhere to the inner wall of the back-connection cylinder, thereby realizing the secondary sealing between the back-insertion joint and the inner wall of the back-connection cylinder and effectively improving the fracturing quality.

[0004] According to the present invention, there is provided a back-insertion joint, including: a tube body with a step on its outer surface, a setting cylinder sleeved on the lower end of the tube body, and a packer rubber ring abutted between the step and the upper end surface of the setting cylinder. The setting cylinder is connected to the tube body through a fixing part. The setting cylinder can cut off the fixing part and, after ascending, jointly extrude the packer rubber ring with its upper end surface and the step, and make the packer rubber ring expand and tightly adhere to the inner wall of the back-connection cylinder.

[0005] In a preferred embodiment, one or more grooves are formed on the outer surface of the tube body above the step, and a sealing rubber ring is arranged inside each groove.

[0006] In a preferred embodiment, two grooves are formed on the outer surface of the tube body.

[0007] In a preferred embodiment, the sealing rubber ring can be in interference fit with the inner wall of the back-connection cylinder.

[0008] In a preferred embodiment, a guiding head is connected to the lower end of the setting cylinder, and the diameter of the guiding head gradually decreases in the direction from top to bottom along the axis of the tube body.

[0009] In a preferred embodiment, the guiding head is made of alloy material.

[0010] In a preferred embodiment, the sealing rubber ring is sealingly connected to the outer surface of the pipe body.

[0011] In a preferred embodiment, the inner wall of the setting cylinder is sealingly connected to the outer surface of the pipe body.

[0012] In a preferred embodiment, the pipe body is formed by connecting a plurality of pipe body short sections through threads, and each pipe body short section is made of a metal material.

[0013] In a preferred embodiment, the fixing part is a shear pin.

[0014] The present invention has at least the following technical effects:

[0015] According to the present invention, there is provided a pipe body with steps on its outer surface, a setting cylinder sleeved on the lower end of the pipe body, and a sealing rubber ring abutted between the steps and the upper end surface of the setting cylinder. The setting cylinder is connected to the pipe body through a fixing part. The setting cylinder can cut off the fixing part and, after ascending, jointly squeeze the sealing rubber ring through its upper end surface and the steps, and make the sealing rubber ring expand and closely adhere to the inner wall of the tie-back cylinder. When the tie-back cylinder is worn due to swabbing or its inner wall is scratched and damaged, resulting in the sealing rubber ring being unable to closely fit the inner wall of the tie-back cylinder after entering the tie-back cylinder, the sealing rubber ring can be squeezed to make it expand and closely adhere to the inner wall of the tie-back cylinder, thereby realizing the secondary sealing between the back-in connector and the inner wall of the tie-back cylinder, effectively improving the fracturing quality.

[0016] According to the present invention, one or more grooves are provided on the outer surface of the pipe body above the steps, and a sealing rubber ring is arranged inside each groove. When the tie-back cylinder is not worn by swabbing and the sealing surface of its inner wall is not damaged, the back-in connector can be in sealing cooperation with the tie-back cylinder through the sealing rubber ring.

[0017] According to the present invention, a guide head is connected to the lower end of the setting cylinder, and the diameter of the guide head gradually decreases in the direction from top to bottom along the axis of the pipe body, so as to facilitate the insertion of the back-in connector into the tie-back cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematically shows a structural diagram of a back-in connector according to an embodiment of the present invention;

[0019] Figure 2 Schematically shows a structural diagram of the sealing rubber ring of a back-in connector according to an embodiment of the present invention;

[0020] Figure 3 Schematically shows a structural diagram of the guide head of a back-in connector according to an embodiment of the present invention.

[0021] In this application, all the attached drawings are schematic drawings, only used to illustrate the principle of the present invention, and are not drawn according to the actual scale. Detailed implementation manners

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the attached drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0023] In the description of the invention, it should be understood that the orientation or positional relationship indicated by terms such as "outer" and "inner" is based on the orientation or positional relationship shown in the attached drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present invention. In the present invention, "a plurality of" refers to two or more.

[0024] In the present invention, unless otherwise clearly defined and limited, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present invention can be understood according to specific situations.

[0025] As Figure 1 shown, the back-insertion joint 100 described in the present invention includes: a pipe body 1 with a step 11 provided on its outer surface, a setting sleeve 2 sleeved on the lower end of the pipe body 1, and a sealing rubber ring 3 abutted between the step 11 and the upper end surface of the setting sleeve 2. The setting sleeve 2 and the pipe body 1 are connected by a fixing part 6. During the process of inserting the back-insertion joint 100 of the present invention downward, the back-insertion joint 100 slowly enters the back-connection cylinder (not shown in the figure) and moves towards its bottom until the lower end of the back-insertion joint 100 encounters resistance and is limited. Continuing to apply pressure downward on the pipe body 1, the setting sleeve 2 can cut off the fixing part 6 under the action of the upward movement trend and move relative to the pipe body 1. The upper end surface of the setting sleeve 2 and the step 11 of the pipe body 1 jointly squeeze the sealing rubber ring 3, and make it expand and closely fit the inner wall of the back-connection cylinder. Optionally, the fixing part 6 can be a shear pin.

[0026] According to the present invention, there are provided a tube body 1 with a step 11 provided on its outer surface, a setting sleeve 2 sleeved on the lower end of the tube body 1, and a sealing rubber ring 3 abutted between the step 11 and the upper end surface of the setting sleeve 2. The setting sleeve 2 is connected to the tube body through a fixing part 6. The setting sleeve 2 can cut off the fixing part 6 and, after ascending, jointly extrude the sealing rubber ring 3 with its upper end surface and the step 11, so that the sealing rubber ring 3 expands and tightly adheres to the inner wall of the back connection cylinder. When the back connection cylinder is worn due to swabbing or its inner wall is scratched and damaged, resulting in the sealing rubber ring being unable to closely fit the inner wall of the back connection cylinder after entering the back connection cylinder, the sealing rubber ring 3 can be extruded to expand and tightly adhere to the inner wall of the back connection cylinder, thereby realizing the secondary sealing between the back insertion joint 100 and the inner wall of the back connection cylinder and effectively improving the fracturing quality.

[0027] As Figure 2 shown, in one or more embodiments, one or more grooves are provided on the outer surface of the tube body 1 above the step 11, and a sealing rubber ring 4 is provided inside each groove. Optionally, two grooves are provided on the outer surface of the tube body 1.

[0028] According to the present invention, one or more grooves are provided on the outer surface of the tube body 1 above the step 11, and a sealing rubber ring 4 is provided inside each groove. When the back connection cylinder is not worn by swabbing and the sealing surface of the inner wall is not damaged, the back insertion joint 100 can be in sealing cooperation with the back connection cylinder through the sealing rubber ring 4.

[0029] In one or more embodiments, the sealing rubber ring 3 is sealingly connected to the outer surface of the tube body 1.

[0030] As Figure 3 shown, in one or more embodiments, a guiding head 5 is connected to the lower end of the setting sleeve 2, and the diameter of the guiding head 5 gradually decreases in the direction from top to bottom along the axis of the tube body 1. Optionally, the guiding head 3 is threadedly connected to the lower end of the setting sleeve 2. Optionally, the guiding head 5 is made of an alloy material, such as aluminum alloy, so as to facilitate removal by swabbing after cementing.

[0031] According to the present invention, a guiding head 5 is connected to the lower end of the setting sleeve 2, and the diameter of the guiding head 5 gradually decreases in the direction from top to bottom along the axis of the tube body 1, so as to facilitate the insertion of the back insertion joint 100 into the back connection cylinder.

[0032] In one or more embodiments, the sealing rubber ring 4 is configured as a ring and is made by alternately stacking rubber rings and metal copper rings. After the back insertion joint 100 is inserted into the back connection cylinder, the sealing rubber ring 4 is in interference fit with the inner wall of the back connection cylinder to achieve plug sealing. By the interference fit between the sealing rubber ring 4 and the inner wall of the back connection cylinder, the displacement of the sealing rubber ring 4 can be avoided.

[0033] In one or more embodiments, the tube body 1 is formed by threadedly connecting a plurality of tube body short sections, and each tube body short section is made of a metal material.

[0034] In one or more embodiments, the inner wall of the setting cylinder 2 is sealingly connected to the outer surface of the pipe body 1, so as to ensure that after the fixing part 6 is sheared, the pipe body 1 remains sealed with the setting cylinder 2 during the continued downward movement.

[0035] In one or more embodiments, the outer diameter of the setting cylinder 2 is the same as the outer diameter of the pipe body 1.

[0036] The following briefly describes the usage process of the backinsertion joint 100 of the present invention. Before cementing, during the downhole drilling and milling, there is solid phase residue in the backconnection cylinder. After pulling out the drill string, the milling shoe is used for milling, and there are many milling marks, which are rough and of different depths, indicating that the backconnection cylinder is damaged during the plug cleaning. There is a risk of unsealing when the conventional backinsertion joint is matched with the backconnection cylinder, so the expansion of the packer rubber ring 3 is adopted for sealing. After the casing is lowered, a bottom detection and trial insertion operation is carried out to observe the friction when the plug enters the backconnection cylinder. At the same time, the pressing tonnage of the backinsertion joint 100 does not exceed 70% of the shearing pressure of the fixing part 6; adjust the arrangement length of the backconnection pipe string and carry out a fracturing operation; quickly clean the casing head after cementing pressure bump, insert the backinsertion joint 100 downward, and slowly insert the backinsertion joint 100 to the bottom of the backconnection cylinder. When encountering resistance at the limit position, continue to apply pressure until the setting cylinder 2 cuts off the fixing part 6; continue to press down the backinsertion joint 100, and the upper end face of the setting cylinder 2 and the step 11 of the pipe body 1 jointly squeeze the packer rubber ring 3, and make it expand and closely fit the inner wall of the backconnection cylinder to achieve complete sealing, thereby realizing the overall sealing of the backconnection pipe string and improving the quality of backconnection cementing.

[0037] The present invention can realize the compression and expansion of the packer rubber ring 3 by controlling the pressing tonnage of the backinsertion plug 100. When the sealing rubber ring of the backinsertion plug cannot be sealed, after the packer rubber ring 3 is squeezed and expanded, the sealing function of the backinsertion plug can be realized again, improving the quality of cementing.

[0038] Although the present invention has been described with reference to the preferred embodiments, various improvements can be made to it and components therein can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A back-insertion connector, characterized in that: include: A tube body with a step on the outer surface, a sealing tube sleeved on the lower end of the tube body, and a sealing rubber ring abutting between the step and the upper end surface of the sealing tube, the sealing tube and the tube body are connected by a fixing part, the sealing tube can cut off the fixing part and squeeze the sealing rubber ring through its upper end surface and the step after moving upward, so that the sealing rubber ring expands and fits tightly against the inner wall of the return tube.

2. The back-insertion connector according to claim 1, characterized in that: The outer surface of the tube body at the upper part of the step is provided with one or more grooves, and a sealing rubber ring is arranged inside each of the grooves.

3. The back-insertion connector according to claim 2, characterized in that: The outer surface of the tube body is provided with two grooves.

4. The back-insertion connector according to claim 2, characterized in that: The sealing rubber ring can be interference fit with the inner wall of the return cylinder.

5. The back-insertion connector according to claim 1 or 2, characterized in that: The lower end of the setting cylinder is connected to a guide head, and the diameter of the guide head gradually decreases from top to bottom along the axis of the tube body.

6. The back-insertion connector according to claim 5, characterized in that: The guide head is made of alloy material.

7. The back-insertion connector according to claim 1 or 2, characterized in that: The sealing rubber ring is sealed and connected to the outer surface of the pipe body.

8. The back-insertion connector according to claim 7, characterized in that: The inner wall of the setting cylinder is sealed and connected to the outer surface of the tube body.

9. The back-insertion connector according to claim 1, characterized in that: The pipe body is formed by connecting a plurality of pipe body short sections through threads, and each of the pipe body short sections is made of metal material.

10. The back-insertion connector according to claim 1, characterized in that: The fixing part is a shear nail.

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