Flexible wellbore connection device and feeding method

Abstract

The invention provides a flexible borehole connecting device which comprises a flexible borehole connecting mechanism, the flexible borehole connecting mechanism comprises a borehole connector, a screen pipe arranged on the downstream portion of the borehole connector and a guide assembly, the guide assembly comprises a spherical sleeve nested in the screen pipe and a rotary inclined guide hinged to the spherical sleeve, and the rotary inclined guide is hinged to the spherical sleeve. The pushing mechanism comprises a central pipe and a first piston, the central pipe is concentrically arranged in the borehole connector, the first piston is fixed outside the central pipe, and a guide hole allowing drilling fluid to pass through is formed in the central pipe. By designing the flexible well hole connecting device, the flexible well hole connecting device can be smoothly fed into the branch well hole when the curvature radius of the branch well hole is too small, and construction of the branch well with the ultra-short radius is further achieved.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas well drilling, and particularly to a flexible wellbore connection device and a feeding method. Background Art

[0002] At present, the multilateral well technology is one of the important means to reduce the development cost of oil and gas wells and improve the recovery rate. This technology drills several branches in a main wellbore to maximize the oil drainage area, expose the oil and gas reservoir, and increase the production of a single well.

[0003] The multilateral well achieves the construction purpose of re-entering the multilateral wellbore through the use of a wellbore connector. The wellbore connector can cooperate with the window section to establish a complete mechanical support, thereby realizing the liner cementing process to establish a re-entry channel for each multilateral wellbore. However, when the curvature radius of the multilateral wellbore is too small, the wellbore connector cannot be smoothly lowered due to insufficient flexibility.

[0004] Therefore, in this field, there is a desire to provide a flexible wellbore connection device to realize the construction of ultra-short radius multilateral wells and solve the above technical problems. Summary of the Invention

[0005] The object of the present invention is to provide a flexible wellbore connection device, which can smoothly feed the flexible wellbore connection mechanism into the multilateral wellbore when the curvature radius of the multilateral wellbore is too small through the design of the flexible wellbore connection device, so as to further realize the construction of ultra-short radius multilateral wells. In addition, a feeding method is also provided.

[0006] According to a first aspect of the present invention, there is provided a flexible wellbore connection device, including a flexible wellbore connection mechanism, which includes a wellbore connector, a screen pipe provided downstream of the wellbore connector, and a guiding assembly. Among them, the guiding assembly includes a spherical sleeve nested in the screen pipe, a rotary whipstock hinged on the spherical sleeve, and

[0007] a pushing mechanism, which includes a central pipe concentrically arranged in the wellbore connector and a first piston fixed outside the central pipe.

[0008] Wherein, a guiding hole allowing drilling fluid to pass through is provided on the central pipe.

[0009] The first piston is configured to be able to make the central pipe descend under the action of the drilling fluid, and the rotary whipstock deflects under the pushing action of the central pipe, thereby guiding the entry into the multilateral wellbore.

[0010] In one embodiment, the lower end surface of the central pipe and the upper end surface of the rotary whipstock are both configured as inclined cutting surfaces.

[0011] In one embodiment, the pushing mechanism further includes a second piston sleeved outside the central tube and slidably connected to the first piston, and an extension sleeve disposed upstream of the central tube, wherein the second piston and the extension sleeve are fixedly connected through a connecting sleeve.

[0012] In one embodiment, the flexible wellbore connection mechanism further includes a short casing disposed upstream of the wellbore connector.

[0013] The pushing mechanism further includes elastic claws concentrically disposed within the short casing and the wellbore connector and fixedly connected to the extension sleeve.

[0014] A clamping groove is formed on the inner wall of the wellbore connector, and the elastic claw includes a protrusion for engaging with the clamping groove.

[0015] In one embodiment, the pushing mechanism further includes a support sleeve disposed downstream of the first piston and fixedly connected to the elastic claw, and a spring disposed between the support sleeve and the second piston.

[0016] In one embodiment, a hook for hanging on the wellbore wall of the branch wellbore port is provided on the outer wall of the wellbore connector.

[0017] In one embodiment, the flexible wellbore connection device further includes a joint disposed upstream of the short casing, and a locking mechanism concentrically disposed within the joint, wherein the locking mechanism includes a first lock sleeve fixedly connected to the extension sleeve, and a second lock sleeve and a lock block housing disposed within the first lock sleeve and separated by a limiting portion, wherein a groove is provided on the second lock sleeve, and a plurality of legs are provided on the lock block housing that extend through the limiting portion and are locked to the second lock sleeve through the groove.

[0018] In one embodiment, the locking mechanism further includes a lock block sleeved outside the legs.

[0019] A limiting groove allowing the lock block to pass through is provided on the first lock sleeve.

[0020] The legs are configured to be axially movable under the driving action of the second lock sleeve, so as to cause the lock block to move radially within the limiting groove.

[0021] According to a second aspect of the present invention, there is provided a method for sending a flexible wellbore connection mechanism into a branch wellbore by using the flexible wellbore connection device as described above, including the following steps:

[0022] S1. By pushing the first lock sleeve to cause the protrusion of the elastic claw to enter the clamping groove, so that the pushing mechanism is suspended on the wellbore connector and lowered into the main wellbore.

[0023] S2. Change the displacement of the drilling fluid to push the central pipe downward by the first piston, so that the rotary whipstock deflects, and fix the angle of the rotary whipstock through the locking mechanism, thereby guiding it into the branch wellbore;

[0024] S3. The wellbore connector is hung on the wellbore wall at the port of the branch wellbore through the hook, and the pushing mechanism and the locking mechanism are lifted out of the wellhead.

[0025] In one embodiment, step S2 further includes a locking step S201:

[0026] First, lift the first lock sleeve, and make the protruding part of the elastic claw withdraw from the card slot of the wellbore connector through the extension sleeve;

[0027] Then, press down the second lock sleeve, make the lock block move radially outward through the support leg, and limit the axial position of the central pipe through the lock block housing, thereby locking the angle of the rotary whipstock.

[0028] Compared with the prior art, the advantages of the present invention are as follows:

[0029] Firstly, by designing a flexible wellbore connection device, the present invention can smoothly send the flexible wellbore connection mechanism into the branch wellbore when the curvature radius of the branch wellbore is too small, so as to further realize the construction of ultra-short radius branch wellbores.

[0030] Secondly, the present invention can change the displacement of the drilling fluid, and make the rotary whipstock deflect by pushing the central pipe downward by the first piston, so as to effectively guide the flexible wellbore connection device smoothly, and ensure that the flexible wellbore connection mechanism can smoothly enter the branch wellbore.

[0031] Thirdly, the present invention can not only lift the first lock sleeve, so that the protruding part of the elastic claw can smoothly withdraw from the card slot of the wellbore connector; but also press down the second lock sleeve, so that the lock block housing axially abuts against the extension sleeve, thereby further restricting the axial position of the central pipe to further restrict the deflection angle of the rotary whipstock. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be described in detail below with reference to the drawings. In the drawings:

[0033] Figure 1 Schematically shows the upper part structure of the flexible wellbore connection device according to the present invention;

[0034] Figure 2 Schematically shows the lower part structure of the flexible wellbore connection device according to the present invention;

[0035] Figure 3 Schematic structural view of the second locking sleeve in the flexible wellbore connection device according to the present invention;

[0036] Figure 4 Schematic structural view of the locking block housing in the flexible wellbore connection device according to the present invention;

[0037] Figure 5 Schematic structural view of the locking block in the flexible wellbore connection device according to the present invention;

[0038] Figure 6 Partial view of the flexible wellbore connection device according to the present invention;

[0039] Figure 7 Upper schematic view when the flexible wellbore connection device according to the present invention is lowered;

[0040] Figure 8 Middle schematic view when the flexible wellbore connection device according to the present invention is lowered;

[0041] Figure 9 Schematically shows the change of the first piston when the drilling fluid displacement is changed;

[0042] Figure 10 Schematic view of the first state of rotary inclination in the flexible wellbore connection device according to the present invention;

[0043] Figure 11 Schematic view of the second state of rotary inclination in the flexible wellbore connection device according to the present invention;

[0044] Figure 12 Schematic view of the position change of the locking structure parts when the first locking sleeve is lifted;

[0045] Figure 13 Schematic view of the position change of the locking structure parts when the second locking sleeve is pressed down.

[0046] In the drawings, like parts are denoted by like reference numerals. The drawings are not drawn to actual scale. Detailed Description of the Invention

[0047] In order to make the technical solutions and advantages of the present invention clearer and more understandable, the exemplary embodiments of the present invention are further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than an exhaustive list of all embodiments. And without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0048] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0049] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two components.

[0050] For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] The present invention will be further described below with reference to the accompanying drawings.

[0052] Figure 1 Schematically shows the upper part structure of the flexible wellbore connection device according to the present invention.

[0053] Figure 2 Schematically shows the lower part structure of the flexible wellbore connection device according to the present invention.

[0054] As Figure 1 and 2 shown, according to the first aspect of the present invention, a flexible wellbore connection device is provided, which includes a flexible wellbore connection mechanism. Preferably, the flexible wellbore connection mechanism includes a wellbore connector 10, a screen pipe 11 arranged downstream of the wellbore connector 10, and a guiding assembly.

[0055] In one embodiment, as Figure 2 shown, the guiding assembly includes a spherical sleeve 12 and a rotary whipstock 13. Preferably, the spherical sleeve 12 is nested in the screen pipe 11, and the rotary whipstock 13 is hinged on the spherical sleeve 12 and can deflect at a certain angle, so as to be able to guide the whole device to smoothly enter the branch wellbore, and its content will be introduced below.

[0056] In a preferred embodiment, the spherical sleeve 12 and the screen pipe 11 are threadedly connected; the rotary whipstock 13 is installed in the spherical sleeve 12 through its spherical geometric relationship, and the spherical part of the rotary whipstock 13 can rotate in the spherical sleeve 12 when stressed, so as to be able to complete the deflection action more easily.

[0057] According to an embodiment of the present invention, as Figure 2As shown, the lower end surface of the central pipe 21 (introduced hereinafter) and the upper end surface of the rotary whipstock 13 are both constructed as mutually matching inclined cutting surfaces. Preferably, the central pipe 21 can be in full contact with the inclined cutting surface of the rotary whipstock 13 during the first-stage downward movement.

[0058] Moreover, during the second-stage downward movement of the central pipe 21, it can cause the rotary whipstock 13 to deflect by a certain angle, so that the rotary whipstock 13 is misaligned with the central pipe 21, thereby enabling the entire device to more easily enter the branch wellbore, which is helpful for subsequent hanging work, the content of which is introduced in the following position.

[0059] In one embodiment, as Figure 2 shown, a screen pipe joint 111 is provided between the wellbore connector 10 and the screen pipe 11. Preferably, the screen pipe joint 111 is respectively threadedly connected to the wellbore connector 10 and the screen pipe 11, thereby ensuring a strong firmness between the wellbore connector 10 and the screen pipe 11.

[0060] In one embodiment, as Figure 1 shown, the flexible wellbore connection device further includes a short casing 14 provided upstream of the wellbore connector 10, and a joint 15 provided upstream of the short casing 14. Preferably, both ends of the short casing 14 are respectively threadedly connected to the joint 15 and the wellbore connector 10, thereby providing a good sealed space for the drilling fluid (introduced hereinafter).

[0061] In addition, the short casing 14 and the joint 15 can jointly play a good protective role for the locking mechanism (introduced hereinafter) and the pushing mechanism (introduced hereinafter), which is helpful for smoothly driving the rotary whipstock 13 to deflect, thereby ensuring that the flexible wellbore connection mechanism can smoothly enter the branch wellbore and hang on the wellbore wall at the port of the branch wellbore.

[0062] In one embodiment of the present invention, a hook (not shown) is provided on the outer wall of the wellbore connector 10. Preferably, the wellbore connector 10 can be smoothly hung on the wellbore wall at the port of the branch wellbore through the hook after entering the well.

[0063] In the present invention, the wellbore connector 10 is entirely transversely slotted (not shown), and the slots are in a continuous petal shape or other shapes that will not cause the wellbore connector 10 to break, and a certain distance is spaced between several slots.

[0064] According to the present invention, the flexible wellbore connection device further includes a pushing mechanism. As Figure 1As shown, the pushing mechanism includes a central tube 21 concentrically arranged within the wellbore connector 10, a first piston 22 fixed outside the central tube 21, and a second piston 23 sleeved outside the central tube 21 and upstream of the first piston 22. Preferably, the first piston 22 and the central tube 21 are formed as a threaded connection to ensure synchronous movement of the two.

[0065] Preferably, the first piston 22 and the second piston 23 form a sealed sliding connection. In other words, a closed space is formed between the first piston 22, the second piston 23, and the central tube 21, which helps the drilling fluid to push the first piston 22 downward, and the content is introduced below.

[0066] In one embodiment, as Figure 1 shown, a guiding hole 211 is provided on the central tube 21. Preferably, the guiding hole 211 is within the range of the closed space composed of the first piston 22, the second piston 23, and the central tube 21, so as to allow the drilling fluid from within the central tube 21 to flow in through the guiding hole 211.

[0067] In the present invention, by changing the flow rate of the drilling fluid, the first piston 22 can move downward under the pressure of the drilling fluid, and at the same time, the central tube 21 will also move downward synchronously under the driving action of the first piston 22.

[0068] During the downward movement, first, the lower end surface of the central tube 21 fully contacts the upper end surface of the rotary whipstock 13; then, the central tube 21 pushes the rotary whipstock 13 downward. Thus, the spherical part of the rotary whipstock 13 rotates within the spherical socket 12 to complete the deflection action, so as to guide the flexible wellbore connection mechanism to smoothly enter the branch wellbore.

[0069] In one embodiment, as Figure 1 shown, the pushing mechanism further includes an extension sleeve 24 provided upstream of the central tube 21, and a connection sleeve 25 provided between the extension sleeve 24 and the second piston 23. Preferably, the connection sleeve 25 forms threaded connections with the extension sleeve 24 and the second piston 23 respectively, so as to enable the extension sleeve 24, the connection sleeve 25, and the second piston 23 to achieve synchronous movement, which helps the subsequent hanging work.

[0070] In one embodiment, as Figure 1 shown, the pushing mechanism further includes an elastic claw 26 concentrically arranged within the short casing 14 and the wellbore connector 10. Preferably, the elastic claw 26 is fixedly connected to the extension sleeve 24. In other words, the elastic claw 26 and the extension sleeve 24 are formed as a threaded connection, that is, the elastic claw 26 can move synchronously with the extension sleeve 24, the connection sleeve 25, and the second piston 23.

[0071] According to the present invention, a clamping groove 101 is formed on the inner wall of the wellbore connector 10, and the elastic claw 26 includes a protrusion 261 for engaging with the clamping groove 101.

[0072] In the present invention, the first lock sleeve 31 is pushed downward, so as to successively cause the extension sleeve 24 and the elastic claw 26 to move downward synchronously. Thus, the protrusion 261 of the elastic claw 26 can smoothly enter the clamping groove 101 of the wellbore connector 10, so that the pushing mechanism can be smoothly suspended on the wellbore connector 10, which helps the rotary whipstock 13 to deflect in the well, and further can play a good guiding role for the whole device.

[0073] Preferably, when the protrusion 261 of the elastic claw 26 does not enter the clamping groove 101 of the wellbore connector 10, there is a gap between the lower end surface of the central tube 21 and the upper end surface of the rotary whipstock 13.

[0074] In one embodiment, as Figure 1 shown, the pushing mechanism further includes a support sleeve 27 disposed downstream of the first piston 22 and fixedly connected to the elastic claw 26, and a spring 28 disposed between the support sleeve 27 and the second piston 23. Preferably, the elastic claw 26 and the support sleeve 27 are formed as a threaded connection.

[0075] In the present invention, when the first piston 22 moves downward to compress the spring 28, the spring 28 can fully store the reset energy. Therefore, when the pushing mechanism and the locking mechanism are lifted out of the wellhead, the reset energy of the spring 28 can provide an upward acting force for them, which helps the pushing mechanism and the locking mechanism to be smoothly lifted.

[0076] Figure 3 FIG. is a schematic structural diagram of the second lock sleeve 32 in the flexible wellbore connection device according to the present invention.

[0077] Figure 4 FIG. is a schematic structural diagram of the lock block housing 33 in the flexible wellbore connection device according to the present invention.

[0078] According to the present invention, as Figure 1 、 3 and FIG. 4 show, the flexible wellbore connection device further includes a locking mechanism. Preferably, the locking mechanism is concentrically arranged in the joint 15 and includes a first lock sleeve 31 fixedly connected to the extension sleeve 24, and a second lock sleeve 32 and a lock block housing 33 disposed in the first lock sleeve 31.

[0079] In one embodiment, as Figure 1As shown, the first locking sleeve 31 is configured as a stepped sleeve, and a limiting portion 311 extending radially inward is formed in the middle thereof. Preferably, the second locking sleeve 32 and the locking block housing 33 are separated by the limiting portion 311, the second locking sleeve 32 is upstream of the limiting portion 311, and the locking block housing 33 is downstream of the limiting portion 311.

[0080] In an embodiment of the present invention, as Figure 1 、 3 and Figure 4 show, a groove 321 is provided on the second locking sleeve 32, and a plurality of legs 34 extending through the limiting portion 311 are provided on the locking block housing 33. Preferably, the legs 34 can be locked with the second locking sleeve 32 through the groove 321, so as to allow the locking block housing 33 and the second locking sleeve 32 to move synchronously.

[0081] In an embodiment, a first through groove 341 for accommodating steel balls and a second through groove 342 for allowing the screw 36 to enter are provided at the end of the leg 34. Preferably, when the end of the leg 34 is aligned with the groove 321 of the second locking sleeve 32, the screw 36 is screwed into the second through groove 342, whereby the steel balls will flow out of the first through groove 341 and enter the groove 321 of the second locking sleeve 32, so as to realize the locking between the second locking sleeve 32 and the leg 34, and further ensure that the second locking sleeve 32 can move synchronously with the locking block housing 33.

[0082] In an embodiment, as Figure 4 shown, the leg 34 is configured in a rod shape, and includes a smooth section 343, a first convex section 344 provided upstream of the smooth section 343, and a second convex section 345 provided downstream of the smooth section 343, so as to be able to drive the locking block 35 (introduced below) to perform radial reciprocating motion, the content of which is introduced below.

[0083] Figure 5 It is a schematic structural diagram of the locking block 35 in the flexible wellbore connection device according to the present invention.

[0084] In an embodiment, as Figure 1 、 4 and Figure 5 show, the locking mechanism further includes a locking block 35 sleeved outside the leg 34, and a limiting groove 312 allowing the locking block 35 to pass through is provided on the first locking sleeve 31. Preferably, the leg 34 is configured to axially move under the driving action of the second locking sleeve 32, so as to cause the locking block 35 to radially move in the limiting groove 312.

[0085] Preferably, the limiting groove 312 is axially within the range of the limiting portion 311.

[0086] Figure 12 It is a schematic diagram of the position change of the locking structure parts when the first locking sleeve 31 is lifted;

[0087] Figure 13 Schematic diagram of the position change of the locking structure parts when pressing down the second lock sleeve 32.

[0088] Preferably, as Figure 12 and 13 shown, when the leg 34 moves from the first raised section 344 to the second raised section 345, the locking block 35 will move radially inwards; when the leg 34 moves from the second raised section 345 to the first raised section 344, the locking block 35 will move radially outwards.

[0089] Figure 6 Partial view of the flexible wellbore connection device according to the present invention;

[0090] Figure 7 Upper schematic view when the flexible wellbore connection device according to the present invention is lowered;

[0091] Figure 8 Middle schematic view when the flexible wellbore connection device according to the present invention is lowered;

[0092] Figure 9 Schematically shows the change of the first piston 22 when changing the drilling fluid displacement;

[0093] Figure 10 First state schematic view of the rotary whipstock 13 in the flexible wellbore connection device according to the present invention;

[0094] Figure 11 Second state schematic view of the rotary whipstock 13 in the flexible wellbore connection device according to the present invention;

[0095] Combined with Figures 6 - 13 to introduce the second aspect of the present invention, which provides a method for sending a flexible experience connection mechanism into a branch wellbore by using the flexible wellbore connection device as described above, including the following steps:

[0096] Step 1, after the completion operation of the lower part of the main wellbore, lower an integrated retrievable window-opening system (not shown), drill the branch wellbore to the designed well depth, and then pull out the drill string and retrieve the whipstock.

[0097] Step 2, referring to Figures 7 - 8 , lower the flexible wellbore connection mechanism through the pushing mechanism.

[0098] Preferably, by pushing the first lock sleeve 31 to make the raised portion 261 of the elastic claw 26 enter the card slot 101, so that the pushing mechanism is suspended on the wellbore connector 10 and lowered into the main wellbore.

[0099] Specifically, push the first lock sleeve 31 downward, thereby successively causing the extension sleeve 24 and the elastic claw 26 to move downward synchronously. Thus, the protrusion 261 of the elastic claw 26 can smoothly enter the slot 101 of the wellbore connector 10, so that the pushing mechanism can be smoothly suspended on the wellbore connector 10 and lowered into the main wellbore.

[0100] In this way, it can help deflect the rotary whipstock 13 in the well, so as to play a good guiding role for the whole device.

[0101] Step three, referring to Figures 9 - 11 , when it is lowered in place and the rotary whipstock 13 needs to guide the whole device into the branch wellbore, change the displacement of the drilling fluid.

[0102] Preferably, by changing the displacement of the drilling fluid, the first piston 22 is pushed to move the central pipe 21 downward, so that the rotary whipstock 13 deflects, and the angle of the rotary whipstock 13 is fixed by the locking mechanism, so as to guide it into the branch wellbore.

[0103] Specifically, by changing the flow rate of the drilling fluid, the first piston 22 can move downward under the pressure of the drilling fluid, and at the same time, the central pipe 21 will also move downward synchronously under the driving action of the first piston 22.

[0104] During the downward movement, first, the lower end surface of the central pipe 21 is in full contact with the upper end surface of the rotary whipstock 13; then, the central pipe 21 pushes the rotary whipstock 13 downward. Thus, the spherical part of the rotary whipstock 13 rotates in the spherical surface sleeve 12 to complete the deflection action, so as to guide the flexible wellbore connection mechanism into the branch wellbore smoothly.

[0105] Step four, the wellbore connector 10 is successfully hooked on the wellbore wall at the port of the branch wellbore through the hook, and the pushing mechanism and the locking mechanism are lifted out of the wellhead.

[0106] In one embodiment, step three further includes a locking step:

[0107] First, referring to Figure 12 , lift the first lock sleeve 31, and make the elastic claw 26 move upward through the extension sleeve 24. Thus, the protrusion 261 of the elastic claw 26 can smoothly withdraw from the slot 101 of the wellbore connector 10. At the same time, the leg 34 will move from the first raised section 344 to the second raised section 345, and the lock block 35 will move radially inward.

[0108] Then, referring to Figure 13, press down the second lock sleeve 32. Under the action of the support leg 34, the lock block 35 will move from the second convex section 345 to the first convex section 344, that is, the lock block 35 will move radially outwards under the action of the limit groove 312. At the same time, the lock block housing 33 will axially abut against the extension sleeve 24, thereby restricting the axial position of the central tube 21 to further restrict the deflection angle of the rotary whipstock 13.

[0109] Compared with the prior art, the advantages of the present invention are as follows:

[0110] Firstly, by designing the flexible wellbore connection device, the present invention can smoothly send the flexible wellbore connection mechanism into the branch wellbore when the curvature radius of the branch wellbore is too small, so as to further realize the construction of ultra-short radius branch wells.

[0111] Secondly, the present invention can change the drilling fluid displacement and push the central tube 21 downward by the first piston 22 to deflect the rotary whipstock 13, so as to effectively guide the flexible wellbore connection device smoothly and ensure that the flexible wellbore connection mechanism can smoothly enter the branch wellbore.

[0112] Thirdly, the present invention can not only lift the first lock sleeve 31 so that the convex part 261 of the elastic claw 26 can smoothly exit the card slot 101 of the wellbore connector 10; but also press down the second lock sleeve 32 so that the lock block housing 33 axially abuts against the extension sleeve 24, thereby restricting the axial position of the central tube 21 and further restricting the deflection angle of the rotary whipstock 13.

[0113] The above is only the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art can easily make changes or variations within the disclosure scope of the present invention, and such changes or variations should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A flexible wellbore connection device, comprising: A flexible wellbore connection mechanism, which includes a wellbore connector (10), a screen pipe (11) arranged downstream of the wellbore connector (10), and a guiding assembly. Among them, the guiding assembly includes a spherical sleeve (12) nested in the screen pipe (11), a rotary whipstock (13) hinged on the spherical sleeve (12), and A pushing mechanism, which includes a central pipe (21) concentrically arranged in the wellbore connector (10), and a first piston (22) fixed outside the central pipe (21), Wherein, a guiding hole (211) allowing drilling fluid to pass through is provided on the central pipe (21), The first piston (22) is configured to be able to make the central pipe (21) move downward under the action of drilling fluid, and the rotary whipstock (13) deflects under the pushing action of the central pipe (21), so as to guide the entry into the branch wellbore.

2. The flexible wellbore connection device according to claim 1, wherein The lower end surface of the central pipe (21) and the upper end surface of the rotary whipstock (13) are both constructed as inclined cutting surfaces.

3. The flexible wellbore connection device according to claim 2, wherein The pushing mechanism further includes a second piston (23) sleeved outside the central pipe (21) and forming a sliding connection with the first piston (22), and an extension sleeve (24) arranged upstream of the central pipe (21). Among them, the second piston (23) and the extension sleeve (24) are fixedly connected through a connection sleeve (25).

4. The flexible wellbore connection device according to claim 3, wherein, The flexible wellbore connection mechanism further includes a short casing (14) arranged upstream of the wellbore connector (10), The pushing mechanism further includes an elastic claw (26) concentrically arranged in the short casing (14) and the wellbore connector (10) and fixedly connected with the extension sleeve (24), A clamping groove (101) is formed on the inner wall of the wellbore connector (10), and the elastic claw (26) includes a convex portion (261) for forming a clamping connection with the clamping groove (101).

5. The flexible wellbore connection device according to claim 4, wherein, The pushing mechanism further includes a support sleeve (27) arranged downstream of the first piston (22) and fixedly connected with the elastic claw (26), and a spring (28) arranged between the support sleeve (27) and the second piston (23).

6. The flexible wellbore connection device according to claim 5, wherein, A hook for hanging on the wellbore wall at the branch wellbore port is provided on the outer wall of the wellbore connector (10).

7. The flexible wellbore connection device according to claim 6, wherein The flexible wellbore connection device further includes a joint (15) arranged upstream of the short casing (14), and a locking mechanism concentrically arranged in the joint (15). Among them, the locking mechanism includes a first lock sleeve (31) fixedly connected with the extension sleeve (24), and a second lock sleeve (32) and a lock block housing (33) arranged in the first lock sleeve (31) and separated by a limiting portion (311). Among them, a groove (321) is provided on the second lock sleeve (32), and a plurality of legs (34) extending through the limiting portion (311) and locked with the second lock sleeve (32) through the groove (321) are provided on the lock block housing (33).

8. The flexible wellbore connection device according to claim 7, wherein, The locking mechanism further includes a lock block (35) sleeved outside the legs (34), A limiting groove (312) allowing the lock block (35) to pass through is provided on the first lock sleeve (31). The support leg (34) is configured to axially move under the driving action of the second lock sleeve (32), so as to cause the lock block (35) to radially move within the limiting groove (312).

9. A method for feeding a flexible wellbore connection mechanism into a branch wellbore by using the flexible wellbore connection device according to any one of claims 1 to 8, comprising the following steps: S1. Push the first lock sleeve (31) to enable the protruding portion (261) of the elastic claw (26) to enter the card slot (101), so that the pushing mechanism is suspended on the wellbore connector (10) and lowered into the main wellbore. S2. Change the drilling fluid displacement to enable the first piston (22) to push the central tube (21) downward, so that the rotary whipstock (13) deflects, and fix the angle of the rotary whipstock (13) through the locking mechanism, so as to guide it into the branch wellbore. S3. The wellbore connector (10) is hung on the wellbore wall of the branch wellbore port through the hook, and the pushing mechanism and the locking mechanism are lifted out of the wellhead.

10. The method according to claim 9, wherein Step S2 further includes a locking step S201: First, lift the first lock sleeve (31), and enable the protruding portion (261) of the elastic claw (26) to withdraw from the card slot (101) of the wellbore connector (10) through the extension sleeve (24). Then, press down the second lock sleeve (32), enable the lock block (35) to radially move outward through the support leg (34), and limit the axial position of the central tube (21) through the lock block housing (33), so as to lock the angle of the rotary whipstock (13).

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