Drilling liner cementing method and device

Abstract

The invention provides a drilling liner well cementation method and device.The drilling liner well cementation method comprises the following steps that a drilling liner is connected with the lower portion of a reverse circulation valve through a sealing insertion pipe, the upper portion of the reverse circulation valve is connected with a tie-back sleeve, and the tie-back sleeve is put down; the tie-back casing pipe is lowered to the preset well depth, a casing pipe rubber plug is lowered to the position of a rubber plug bump-pressure short section of a tail pipe for replacement, well sealing is conducted after well cementation and slurry replacement are finished, and then annulus pressure building is conducted; the sliding sleeve cuts off the fixing part and moves downwards in the axial direction of the central pipe, the lower end face of the sliding sleeve and the step jointly extrude the elastic piece, meanwhile, the inner wall of the sliding sleeve is separated from the circulation hole, and reverse circulation well washing is conducted through the circulation hole; after the cement slurry above the tail pipe is washed out, pressure relief is conducted, the sliding sleeve moves upwards in the axial direction under the action of the elastic piece, and the circulating hole is plugged again. According to the invention, well cementation tool accessories above a rubber plug of a tail pipe can be prevented from being drilled, and the steps of milling a tie-back barrel and putting a tie-back sleeve into the tie-back barrel are omitted.

Description

Technical Field

[0001] This invention relates to the field of cementing tools for oil and gas wells, and more specifically, to a tailpipe cementing method and apparatus. Background Technology

[0002] Currently, for ultra-low porosity and ultra-low permeability reservoirs, horizontal well development mainly relies on volumetric fracturing. To control costs, tailpipe reconnection fracturing tools have been introduced. This involves connecting the reconnection tubing string to a tailpipe hanger at the top of the tubing string via a reconnection tool. After fracturing, the reconnection tubing string can be retrieved, significantly reducing operating costs. After tailpipe cementing is completed and the cement slurry has set, a separate drilling operation is required to remove cementing tools and accessories above the tailpipe plug. Another drilling operation is then performed to mill the reconnection tubing and run in tools such as the reconnection casing for reconnection. These multiple drilling operations waste considerable time, resulting in low well completion efficiency and delays in subsequent production operations. Summary of the Invention

[0003] One objective of this invention is to provide a tailpipe cementing method and apparatus to avoid the need to drill and remove cementing tools and accessories above the tailpipe plug separately after the cement slurry has set. This also eliminates the need for subsequent drilling to mill the return casing and run the return casing. After sealing the circulation hole, only one drilling operation is required to remove the tailpipe plug before proceeding with the subsequent well completion work. This improves well completion efficiency and ensures the smooth progress of subsequent operations.

[0004] According to the present invention, a tailpipe cementing method is provided, comprising the following steps: S1, connecting the tailpipe to the lower part of a reverse circulation valve via a sealing insert, connecting the upper part of the reverse circulation valve to a return casing, and lowering the return casing, wherein the reverse circulation valve comprises: a central pipe with a stepped outer surface, a sliding sleeve fitted on the outer surface of the central pipe, and an elastic element disposed between the stepped part and the lower end face of the sliding sleeve, the sliding sleeve being fixed to the central pipe by a fixing part, and the inner wall of the sliding sleeve sealing the circulation hole opened on the central pipe; S2, connecting the return casing S3. The casing rubber plug is lowered to the predetermined well depth and inserted into the short section of the tailpipe to replace it. After cementing and slurry replacement, the well is sealed and then the annulus is pressurized. S4. The sliding sleeve shears off the fixed part and moves downward along the axial direction of the central tube. Its lower end face and the step together squeeze the elastic element. At the same time, the inner wall of the sliding sleeve disengages from the circulation hole and performs reverse circulation well washing through the circulation hole. S5. After the cement slurry above the tailpipe is washed out, the pressure is released. The sliding sleeve moves upward along the axial direction under the action of the elastic element and re-seals the circulation hole.

[0005] In a preferred embodiment, the tailpipe cementing method further includes: S5, during subsequent in-pipe operations, pressurizing the pipe to ensure that the sliding sleeve always seals the circulation hole.

[0006] According to the present invention, a tailpipe cementing device is provided, comprising: a tailpipe, a reverse circulation valve, a sealing insert, and a return sleeve. The tailpipe is connected to the lower part of the reverse circulation valve via the sealing insert, and the upper part of the reverse circulation valve is connected to the return sleeve. The reverse circulation valve comprises: a central tube with a stepped outer surface, a sliding sleeve fitted onto the outer surface of the central tube, and an elastic element disposed between the step and the lower end face of the sliding sleeve. The sliding sleeve is fixed to the central tube by a fixing part, and the inner wall of the sliding sleeve blocks a circulation hole opened on the central tube. The sliding sleeve can shear off the fixing part and move downward along the axial direction of the central tube, pressing the elastic element together with its lower end face and the step. Simultaneously, the inner wall of the sliding sleeve disengages from the circulation hole. The sliding sleeve can move upward along the axial direction under the action of the elastic element and re-seal the circulation hole.

[0007] In a preferred embodiment, the inner wall of the sliding sleeve is provided with two protrusions that protrude radially inward. Both protrusions abut against the outer surface of the central tube. A sealing cavity is formed between the inner wall of the sliding sleeve, the outer surface of the central tube, and the opposing surfaces of the two protrusions. At least one pressure relief hole communicating with the sealing cavity is provided on the central tube.

[0008] In a preferred embodiment, the reverse circulation valve further includes an upper connector connected to the upper part of the central tube and a lower connector connected to the lower part of the central tube, the upper connector being connected to the return sleeve and the lower connector being connected to the sealing insert.

[0009] In a preferred embodiment, the outer surface of the central tube is sealed to the inner wall of the upper connector by a sealing ring.

[0010] In a preferred embodiment, the sealing cannula includes: a double male connector and a cannula upper connector connected to the male thread of the lower connector via an upper female thread, wherein the upper male thread of the double male connector is connected to the lower female thread of the cannula upper connector.

[0011] In a preferred embodiment, the sealing cannula further includes: an upper straightening section, a sealing cannula body, a horseshoe-shaped reconnector plug, and a lower connector of the body. The lower male thread of the double male connector is connected to the upper female thread of the upper straightening section, and the lower female thread of the upper straightening section is connected to the male thread of the horseshoe-shaped reconnector plug. The inner wall of the sealing cannula body is connected to the horseshoe-shaped reconnector plug via a reverse nut, and the lower end of the sealing cannula body is integrally connected to the lower connector of the body. The lower connector of the body is connected to the tail tube via the sealing cannula male thread.

[0012] In a preferred embodiment, the inner wall of the sliding sleeve and the outer surface of the central tube at the upper and lower parts of the circulation hole are respectively sealed by at least one sealing ring.

[0013] In a preferred embodiment, the outer surface of the central tube below the pressure relief hole is sealed to the inner wall of the sliding sleeve by at least one sealing ring.

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

[0015] According to the present invention, by connecting the reverse circulation valve, sealing pipe, tailpipe, and return casing together and running them in a single operation, and utilizing the reverse circulation valve to flush out the mud above the tailpipe, the cementing tool accessories above the tailpipe plug are avoided from being drilled separately after the cement slurry has set. This also eliminates the need for subsequent drilling to mill the return casing and run the return casing again. After sealing the circulation hole, only one drilling operation is required to remove the tailpipe plug before proceeding with subsequent well completion operations. This improves well completion efficiency and ensures smooth operation of later stages. Furthermore, because the reverse circulation valve, sealing pipe, tailpipe, and return casing are connected and run in a single operation, only conventional casing plugs are needed for mud replacement, avoiding the use of a combination of drill pipe and tailpipe plugs, thus preventing plug jamming.

[0016] According to the present invention, the lower male thread of the double male connector is fixedly connected to the upper female thread of the upper centralizing sub by threads, and the lower female thread of the upper centralizing sub is fixedly connected to the male thread of the horseshoe-shaped reconnection plug by threads. The inner wall of the sealing pipe body is connected to the horseshoe-shaped reconnection plug by a reverse nut. The lower end of the sealing pipe body is integrally connected to the lower connector of the body, and the lower connector of the body is connected to the tail pipe by the male thread of the sealing pipe. After the fracturing operation is completed, by lifting the reconnecting casing, the reverse nut in the sealing pipe is in a tensioned state, and then the pipe is rotated forward and released. The sealing pipe body and the lower connector of the body remain in the well, allowing the reconnecting casing, the reverse circulation valve, and part of the sealing pipe to be retrieved, thus enabling recycling and saving operating costs. Attached Figure Description

[0017] Figure 1 A flowchart illustrating the tailpipe cementing method according to the present invention is shown schematically.

[0018] Figure 2 A schematic diagram of the overall structure of the reverse circulation valve of the tailpipe cementing device according to the present invention is shown.

[0019] Figure 3 A schematic diagram of the overall structure of the sealing insert of the tailpipe cementing device according to the present invention is shown.

[0020] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0021] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0022] In the description of this invention, it should be understood that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0023] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0024] like Figures 1 to 3 As shown, the tailpipe cementing method 100 of the present invention includes the following steps: S1, connecting the tailpipe to the lower part of the reverse circulation valve 1 through the sealing insertion pipe 2, connecting the upper part of the reverse circulation valve 1 to the return casing, and lowering the return casing. The reverse circulation valve 1 includes: a central pipe 17 with a step 16 on its outer surface, a sliding sleeve 12 sleeved on the outer surface of the central pipe 17, and an elastic member 14 disposed between the lower end face of the step 16 and the sliding sleeve 12. The sliding sleeve 12 is fixed to the central pipe 17 by the fixing part 13, and the inner wall of the sliding sleeve 12 blocks the circulation hole 15 opened on the central pipe 17.

[0025] S2. Lower the casing to the predetermined well depth, and insert the casing plug into the plug-pressing section of the tailpipe for displacement. After cementing and slurry displacement are completed, seal the well and pressurize the annulus through the reverse circulation pipeline. It should be noted that in this invention, slurry displacement, well sealing, and annulus pressurization are all performed using conventional cementing equipment and corresponding cementing procedures.

[0026] S3. Under the axial pressure generated by the annular pressure buildup, the sliding sleeve 12 shears off the fixed part 13 and moves downward along the axial direction of the central tube 17. Its lower end face and the step 16 together squeeze the elastic element 14. At the same time, the inner wall of the sliding sleeve 12 disengages from the circulation hole 15 and performs reverse circulation well washing through the circulation hole 15 to clean the mud in the section above the tailpipe.

[0027] S4. After the mud above the tailpipe is washed out, the pressure is released. Under the action of the elastic force of the elastic element 14, the sliding sleeve 12 moves upward in the axial direction and re-seals the circulation hole 15.

[0028] According to the present invention, by connecting the reverse circulation valve 1, the sealing pipe 2, the tailpipe, and the return casing together and running them in, and utilizing the reverse circulation valve 1 to wash out the mud above the tailpipe, the cementing tool accessories above the tailpipe plug are avoided from being drilled separately after the cement slurry has set. This also eliminates the need for subsequent drilling to mill the return casing and run the return casing again. After sealing the circulation hole 15, only one drilling operation is needed to remove the tailpipe plug before proceeding with subsequent well completion operations. This improves well completion efficiency and ensures smooth operation of later stages. Furthermore, because the reverse circulation valve 1, the sealing pipe 2, the tailpipe, and the return casing are connected together and run in, during mud replacement, only conventional casing plugs are needed for replacement, avoiding the use of a combination of drill pipe and tailpipe plugs, thus preventing plug jamming.

[0029] In one or more embodiments, the tailpipe cementing method 100 of the present invention further includes: S5, subsequent in-pipe operations (e.g., fracturing operations and oil production operations) are performed to ensure that the sliding sleeve always seals the circulation hole by pressurizing the in-pipe.

[0030] Based on the above-described tailpipe cementing method, the present invention also provides a tailpipe cementing device 200, comprising: a tailpipe, a reverse circulation valve 1, a sealing insert 2, and a return casing. The tailpipe is connected to the lower part of the reverse circulation valve 1 via the sealing insert 2, and the upper part of the reverse circulation valve 1 is connected to the return casing. The reverse circulation valve 1 comprises: a central tube 17 with a step 16 on its outer surface, a sliding sleeve 12 fitted onto the outer surface of the central tube 17, and an elastic member 14 disposed between the step 16 and the lower end face of the sliding sleeve 12. The sliding sleeve 12 is fixed to the central tube 17 by a fixing part 13, and when the sliding sleeve 12 and the central tube 17 are fixed, the inner wall of the sliding sleeve 12 can block the circulation hole 15 opened on the central tube 17, and reverse circulation well washing can be performed by opening the circulation hole 15.

[0031] Under axial force, the sliding sleeve 12 can shear off the fixed part 13, causing it to move downward relative to the central tube 17 in the axial direction. It also presses against the elastic element 14 through its lower end face and step 16. Simultaneously, the inner wall of the sliding sleeve 12 disengages from the circulation hole 15, opening the circulation hole 15 on the central tube 17 for reverse circulation well washing. After washing out excess cement slurry above the tailpipe section, the pressure can be released. At this point, the sliding sleeve 12 moves upward in the axial direction under the rebound force of the elastic element 14, and re-seals the circulation hole 15 through its inner wall to complete the tailpipe cementing operation. Optionally, the fixed part 13 can be a shearing pin, which drives into the outer wall of the central tube 17 through the inner wall of the sliding sleeve 12, and the elastic element 14 can be a spring.

[0032] In one or more embodiments, two protrusions 19 protruding radially inward are provided on the inner wall of the sliding sleeve 12. Both protrusions 19 abut against the outer surface of the central tube 17. A sealing cavity 110 is formed between the inner wall of the sliding sleeve 12, the outer surface of the central tube 17, and the opposing surfaces of the two protrusions 19. At least one pressure relief hole 111 communicating with the sealing cavity 110 is provided on the central tube 17. After the mud above the tail pipe is washed out, the pressure is relieved through the pressure relief hole 111.

[0033] In one or more embodiments, the reverse circulation valve 1 further includes an upper connector 11 connected to the upper part of the central tube 17 and a lower connector 113 connected to the lower part of the central tube 17. The upper connector 11 is connected to a return sleeve, a sliding sleeve 12 is disposed at the lower part of the upper connector 11, and the lower connector 113 is connected to a sealing insert 2. Optionally, the upper part of the central tube 17 is threadedly fixedly connected to the upper connector 11, thereby facilitating the installation and removal of the upper connector 11, and the lower part of the central tube 17 is threadedly fixedly connected to the lower connector 113, thereby facilitating the installation and removal of the lower connector 113. The outer surface of the central tube 17 is sealed to the inner wall of the upper connector 11 by a sealing ring 112.

[0034] In one or more embodiments, the inner wall of the sliding sleeve 12 is sealed to the outer surface of the central tube 17 at the upper part and the outer surface of the lower part of the circulation hole 15 by at least one sealing ring 112.

[0035] In one or more embodiments, the outer surface of the central tube 17 below the pressure relief hole 111 is sealed to the inner wall of the sliding sleeve 12 by at least one sealing ring.

[0036] In one or more embodiments, the sealing cannula 2 includes: a double male connector 22 and a cannula upper connector 21 connected to the male thread of the lower connector 113 via an upper female thread; the upper male thread of the double male connector 22 is connected to the lower female thread of the cannula upper connector 21. Optionally, the lower female thread of the cannula upper connector 21 and the upper male thread of the double male connector 22 are fixedly connected by threads, thereby enabling the function of changing the thread of different sleeves.

[0037] In one or more embodiments, the sealing casing 2 further includes: an upper centralizing sub 23, a sealing casing body 24, a horseshoe-shaped reconnection plug 25, and a lower connector 26. The lower male thread of the double male connector 22 is threadedly fixed to the upper female thread of the upper centralizing sub 23, and the lower female thread of the upper centralizing sub 23 is threadedly fixed to the male thread of the horseshoe-shaped reconnection plug 25. The inner wall of the sealing casing body 24 is connected to the horseshoe-shaped reconnection plug 25 via a reverse nut 27. The lower end of the sealing casing body 24 is integrally connected to the lower connector 26, and the lower connector 26 is connected to the tailpipe via a sealing casing male thread. After the fracturing operation is completed, by lifting the reconnection casing, the reverse nut 27 in the sealing casing 2 is in a tensioned state. Then, by rotating it forward and releasing it, the sealing casing body 24 and the lower connector 26 remain in the well. The reconnection casing, the reverse circulation valve 1, and part of the sealing casing 2 can be retrieved, allowing for recycling and saving operating costs.

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

Claims

1. A tailpipe cementing method, comprising the following steps: S1. Connect the tail pipe to the lower part of the reverse circulation valve through a sealing insert, and connect the upper part of the reverse circulation valve to the return sleeve, and lower the return sleeve. The reverse circulation valve includes: a central pipe with a step on its outer surface, a sliding sleeve fitted on the outer surface of the central pipe, and an elastic element disposed between the step and the lower end face of the sliding sleeve. The sliding sleeve is fixed to the central pipe by a fixing part, and the inner wall of the sliding sleeve blocks the circulation hole opened on the central pipe. S2. Run the back-connecting casing to the predetermined well depth, and insert the casing rubber plug into the rubber plug-pressing short section of the tail pipe and replace it. After the cementing and slurry replacement is completed, seal the well and then pressurize the annulus. S3. The sliding sleeve cuts off the fixed part and moves downward along the axial direction of the central tube. Its lower end face and the step together squeeze the elastic element. At the same time, the inner wall of the sliding sleeve disengages from the circulation hole and performs reverse circulation well cleaning through the circulation hole. S4. After the cement slurry above the tailpipe is washed out, the pressure is released. Under the action of the elastic element, the sliding sleeve moves upward in the axial direction and re-seals the circulation hole.

2. The tailpipe cementing method according to claim 1, characterized in that, Also includes: S5. During subsequent pipe operations, the sliding sleeve is kept sealed in the circulation hole by pressurizing inside the pipe.

3. A tailpipe cementing device, characterized in that, include: The device includes a tailpipe, a reverse circulation valve, a sealing insert, and a return sleeve. The tailpipe is connected to the lower part of the reverse circulation valve via the sealing insert, and the upper part of the reverse circulation valve is connected to the return sleeve. The reverse circulation valve includes: a central tube with a step on its outer surface, a sliding sleeve fitted on the outer surface of the central tube, and an elastic element disposed between the step and the lower end face of the sliding sleeve. The sliding sleeve is fixed to the central tube by a fixing part, and the inner wall of the sliding sleeve blocks the circulation hole opened on the central tube. The sliding sleeve can cut off the fixed part and move downward along the axial direction of the central tube. Its lower end face and the step together squeeze the elastic element. At the same time, the inner wall of the sliding sleeve disengages from the circulation hole. The sliding sleeve can move upward along the axial direction under the action of the elastic element and re-seal the circulation hole.

4. The tailpipe cementing device according to claim 3, characterized in that, The inner wall of the sliding sleeve has two protrusions that protrude radially inward. Both protrusions abut against the outer surface of the central tube. A sealing cavity is formed between the inner wall of the sliding sleeve, the outer surface of the central tube, and the opposing surfaces of the two protrusions. At least one pressure relief hole communicating with the sealing cavity is provided on the central tube.

5. The tailpipe cementing device according to claim 3, characterized in that, The reverse circulation valve further includes an upper connector connected to the upper part of the central tube and a lower connector connected to the lower part of the central tube, the upper connector being connected to the return sleeve and the lower connector being connected to the sealing insert.

6. The tailpipe cementing device according to claim 5, characterized in that, The outer surface of the central tube is sealed to the inner wall of the upper connector by a sealing ring.

7. The tailpipe cementing device according to claim 5, characterized in that, The sealing cannula includes: a double male connector and an upper cannula connector that is connected to the male thread of the lower connector via an upper female thread, wherein the upper male thread of the double male connector is connected to the lower female thread of the upper cannula connector.

8. The tailpipe cementing device according to claim 7, characterized in that, The sealing cannula also includes: an upper straightening subsection, a sealing cannula body, a horseshoe-shaped reconnection plug, and a lower connector of the body. The lower male thread of the double male connector is connected to the upper female thread of the upper straightening short section, the lower female thread of the upper straightening short section is connected to the male thread of the horseshoe-shaped reconnection plug, the inner wall of the sealing tube body is connected to the horseshoe-shaped reconnection plug through a reverse nut, and the lower end of the sealing tube body is integrally connected to the lower connector of the body, and the lower connector of the body is connected to the tail tube through the sealing tube male thread.

9. The tailpipe cementing device according to claim 4, characterized in that, The inner wall of the sliding sleeve and the outer surface of the central tube at the upper and lower parts of the circulation hole are respectively sealed and connected by at least one sealing ring.

10. The tailpipe cementing device according to claim 9, characterized in that, The central tube is sealed between its outer surface below the pressure relief hole and the inner wall of the sliding sleeve by at least one sealing ring.

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