Auxiliary suspension device for complex well bore structure

Abstract

The utility model discloses an auxiliary suspension device for a complex well bore structure. The auxiliary suspension device comprises a suspension head, a bearing ring, a casing hanger and a sealing assembly. A first clamping groove matched with the bearing ring is formed in the inner circumferential face of the hanging head, a second clamping groove matched with the bearing ring is formed in the outer circumferential face of the casing hanger, and a third clamping groove matched with a feeding tool is formed in the inner circumferential face of the casing hanger. The sealing assembly is arranged between the casing hanger and the hanging head in a sleeving mode, a limiting circular bead corresponding to the sealing assembly is arranged on the peripheral face of the casing hanger, and the sealing assembly has a feeding state away from the limiting circular bead and a sealing state abutting against the limiting circular bead. The suspension head of the auxiliary suspension device is directly connected to the bottom of the underwater wellhead head or indirectly connected to the bottom of the underwater wellhead head through a sleeve, the sleeve hanger is hung on the bearing ring on the inner side of the suspension head in a sitting mode, the requirement for increasing sleeve layers can be met without replacing an existing underwater wellhead device, and the sealing assembly is used for sealing a gap between the sleeve hanger and the suspension head. And well liquid leakage is prevented.

Description

Technical Field

[0001] The utility model relates to the technical field of marine oil and gas exploitation, in particular to an auxiliary suspension device for a complex wellbore structure. Background Art

[0002] With the continuous advancement of drilling technology, offshore oil and gas development is gradually moving towards deepwater and ultra-deepwater areas. During offshore drilling, when encountering complex formations such as high-pressure oil, gas and water layers, leakage layers and collapse layers, in order to drill to the target formation, it is usually necessary to set a technical casing between the surface casing and the oil layer casing to isolate the complex formations that are difficult to control, so as to ensure the smooth progress of drilling work. The level of technical casing setting depends on the number of complex layers. Since the number of casing layers that can be suspended by the underwater wellhead itself is fixed, the inner cavity structure of the wellhead is difficult to change under the constraints of many factors, and its suspension capacity is also subject to certain restrictions, making it difficult to meet the demand for increasing the casing suspension position. When the number of casing layers required for complex formations exceeds the number of casing layers suspended by the underwater wellhead, an auxiliary suspension device is required to increase the casing layer. Therefore, it is necessary to develop an auxiliary suspension device independent of the underwater wellhead to meet the demand for increasing the casing layer for complex wellbore structures. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide an auxiliary suspension device for a complex wellbore structure, which can meet the demand of the complex wellbore structure for increasing the casing layer.

[0004] In order to solve the above technical problems, the technical solution adopted by the utility model is: an auxiliary suspension device for a complex wellbore structure, comprising a suspension head, a load-bearing ring, a casing hanger and a sealing assembly; a first clamping groove cooperating with the load-bearing ring is provided on the inner circumference of the suspension head, a second clamping groove is provided on the inner circumference of the load-bearing ring, a first limiting protrusion cooperating with the second clamping groove is provided on the outer circumference of the casing hanger, and a third clamping groove cooperating with a running tool is provided on the inner circumference of the casing hanger;

[0005] The sealing assembly is sleeved between the casing hanger and the hanging head. A limiting shoulder is provided on the outer circumferential surface of the casing hanger corresponding to the sealing assembly. The sealing assembly has a feeding state away from the limiting shoulder and a sealing state against the limiting shoulder.

[0006] Furthermore, the sealing assembly is provided with a first breakable screw, and the outer peripheral surface of the casing hanger is provided with a first limiting hole cooperating with the first breakable screw, and the first breakable screw is used to keep the sealing assembly in the sent-in state.

[0007] Furthermore, the sealing assembly includes a movable component, an elastic rubber tube and a sealing ring; the elastic rubber tube is arranged on the outer periphery of the movable component, and the sealing ring is arranged on the inner periphery of the movable component.

[0008] Furthermore, the movable component includes an excitation ring and a support ring, the excitation ring is sleeved on the outer circumference of the support ring, a receiving groove is provided on the outer circumferential surface of the support ring, the elastic rubber tube is arranged in the receiving groove, a first ring groove is opened on the top surface of the elastic rubber tube, and a convex ring for inserting into the first ring groove is provided at the bottom end of the excitation ring.

[0009] Furthermore, the movable assembly also includes a second breakable screw, which is used to lock the relative positions of the excitation ring and the support ring so that the convex ring is kept at a position away from the elastic rubber cylinder.

[0010] Furthermore, the excitation ring includes an annular body and a plurality of claws connected to the top of the annular body, the top ends of the plurality of claws are provided with inwardly protruding flanges, the inner side surfaces of the plurality of claws are provided with second limiting protrusions, and the outer peripheral surface of the casing hanger is provided with a fourth groove corresponding to the second limiting protrusion, and when the sealing assembly is in a sealing state, the second limiting protrusion and the fourth groove are clamped and matched.

[0011] Furthermore, the sealing assembly also includes a pin shaft, which is installed on the excitation ring. The outer peripheral surface of the support ring is provided with a long groove that slidably cooperates with the pin shaft, and the length direction of the long groove is vertically arranged.

[0012] Furthermore, a second annular groove is provided on the inner circumferential surface of the movable component, and the sealing ring is arranged in the second annular groove.

[0013] Furthermore, the first limiting protrusion is arranged on the limiting shoulder.

[0014] Furthermore, a reflux groove is provided on the limit shoulder, and the reflux groove connects the top surface and the bottom surface of the limit shoulder; a reflux hole is opened on the casing hanger, and the reflux hole connects the outer circumference and the inner circumference of the casing hanger, and when the sealing assembly is in the sent-in state, the outer opening of the reflux hole is located below the sealing assembly, and when the sealing assembly is in the sealing state, the sealing assembly covers the outer opening of the reflux hole.

[0015] The beneficial effects of the utility model are as follows: the suspension head of the auxiliary suspension device for complex wellbore structures is directly or indirectly connected to the bottom of the underwater wellhead head through casing, and the casing hanger is lowered into the inner cavity of the suspension head so that it is suspended on the bearing ring inside the suspension head, and the need to increase the casing layer can be met without replacing the existing underwater wellhead device; the contact area with the casing hanger is increased by shrinking the bearing ring, which not only ensures a larger inner diameter but also meets the bearing requirements, and has high applicability. The sealing assembly of the inner cavity of the auxiliary suspension device can close the gap between the casing hanger and the suspension head to prevent well fluid leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the overall structure of an auxiliary suspension device for a complex wellbore structure according to Embodiment 1 of the utility model;

[0017] Figure 2 This is a partial structural schematic diagram of an auxiliary suspension device for a complex wellbore structure according to Embodiment 1 of the utility model (the suspension head is hidden);

[0018] Figure 3 A cross-sectional view of an auxiliary suspension device for a complex wellbore structure according to Embodiment 1 of the utility model Figure 1 (The sealing assembly is in the feeding state);

[0019] Figure 4 for Figure 3 A magnified picture of the details of part A;

[0020] Figure 5 for Figure 3 A magnified view of the details of part B;

[0021] Figure 6 A cross-sectional view of an auxiliary suspension device for a complex wellbore structure according to Embodiment 1 of the utility model Figure 2 (The sealing assembly is in a sealed state);

[0022] Figure 7 for Figure 6 A magnified view of the details of part C in the middle;

[0023] Figure 8 for Figure 6 A magnified view of the details of part D in the middle;

[0024] Fig. 9 A cross-sectional view of an auxiliary suspension device for a complex wellbore structure according to Embodiment 1 of the utility model Figure 3 (The sealing assembly is in the feeding state);

[0025] Fig.10 for Fig. 9 The enlarged detail of part E in the middle;

[0026] Fig.11 A cross-sectional view of an auxiliary suspension device for a complex wellbore structure according to Embodiment 1 of the utility model Figure 4 (The sealing assembly is in the feeding state);

[0027] Fig.12 for Fig.11 Enlarged detail of part F.

[0028] Description of labels:

[0029] 1. Suspension head; 11. First card slot;

[0030] 2. Carrying ring; 21. Second slot;

[0031] 3. Casing hanger; 31. First limiting protrusion; 32. Third clamping groove; 33. Limiting shoulder; 34. Fourth clamping groove; 35. Reflux groove; 36. Reflux hole;

[0032] 4. Sealing assembly; 41. First breakable screw; 42. Elastic rubber sleeve; 421. First ring groove; 43. Sealing ring; 44. Excitation ring; 441. Protruding ring; 442. Annular body; 443. Clamping claw; 444. Flanging; 445. Second limiting protrusion; 45. Support ring; 451. Receiving groove; 452. Long groove; 453. Second ring groove; 46. Second breakable screw; 47. Pin shaft. DETAILED DESCRIPTION

[0033] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes and the accompanying drawings.

[0034] Please refer to Figures 1 to 12 , an auxiliary suspension device for a complex wellbore structure, comprising a suspension head 1, a load ring 2, a casing hanger 3 and a sealing assembly 4; a first groove 11 cooperating with the load ring 2 is provided on the inner circumference of the suspension head 1, a second groove 21 is provided on the inner circumference of the load ring 2, a first limiting protrusion 31 cooperating with the second groove 21 is provided on the outer circumference of the casing hanger 3, and a third groove 32 cooperating with a running tool is provided on the inner circumference of the casing hanger 3;

[0035] The sealing assembly 4 is sleeved between the casing hanger 3 and the hanging head 1. A limiting shoulder 33 is provided on the outer peripheral surface of the casing hanger 3 corresponding to the sealing assembly 4. The sealing assembly 4 has a sending state away from the limiting shoulder 33 and a sealing state against the limiting shoulder 33.

[0036] From the above description, it can be seen that the beneficial effects of the utility model are: the suspension head of the auxiliary suspension device is directly or indirectly connected to the bottom of the underwater wellhead head through the casing, and the casing hanger 3 is lowered into the inner cavity of the suspension head 1 so that it is suspended on the bearing ring 2 inside the suspension head 1, and the need to increase the casing layer can be realized without replacing the existing underwater wellhead device; the contact area with the casing hanger 3 is increased by shrinking the bearing ring 2, which not only ensures a larger inner diameter but also meets the load-bearing requirements, and has high applicability. The sealing assembly 4 in the inner cavity of the auxiliary suspension device can close the gap between the casing hanger 3 and the suspension head 1 to prevent well fluid leakage.

[0037] Furthermore, the sealing assembly 4 is provided with a first breakable screw 41, and the outer peripheral surface of the casing hanger 3 is provided with a first limiting hole cooperating with the first breakable screw 41, and the first breakable screw 41 is used to keep the sealing assembly 4 in the sent-in state.

[0038] As can be seen from the above description, the first breakable screw 41 can prevent the sealing assembly 4 from accidentally sliding down during the insertion stage of the auxiliary suspension device to close the return hole 36 of the casing hanger 3 and the gap between the casing hanger 3 and the suspension head 1.

[0039] Furthermore, the sealing assembly 4 includes a movable component, an elastic rubber tube 42 and a sealing ring 43; the elastic rubber tube 42 is arranged on the outer periphery of the movable component, and the sealing ring 43 is arranged on the inner periphery of the movable component.

[0040] It can be seen from the above description that the elastic rubber cylinder 42 is used to close the gap between the movable component and the hanging head 1 , and the sealing ring 43 is used to close the gap between the movable component and the casing hanger 3 .

[0041] Furthermore, the movable component includes an excitation ring 44 and a support ring 45, the excitation ring 44 is sleeved on the outer periphery of the support ring 45, the outer peripheral surface of the support ring 45 is provided with a receiving groove 451, the elastic rubber tube 42 is arranged in the receiving groove 451, the top surface of the elastic rubber tube 42 is provided with a first annular groove 421, and the bottom end of the excitation ring 44 is provided with a convex ring 441 for inserting into the first annular groove 421.

[0042] From the above description, it can be seen that when the sealing assembly 4 enters the sealing state, the convex ring 441 is inserted into the first ring groove 421 of the elastic rubber tube 42, and the elastic rubber tube 42 presses the inner wall surface of the suspension head 1 and the outer wall surface of the support ring 45 under the extrusion of the convex ring 441, thereby closing the gap between the support ring 45 and the suspension head 1.

[0043] Furthermore, the movable assembly further comprises a second breakable screw 46 , and the second breakable screw 46 is used to lock the relative positions of the excitation ring 44 and the support ring 45 so as to keep the convex ring 441 at a position away from the elastic rubber tube 42 .

[0044] As can be seen from the above description, the second breakable screw 46 can prevent the excitation ring 44 from accidentally sliding down relative to the support ring 45 during the insertion stage and squeezing the elastic rubber tube 42, causing the elastic rubber tube 42 to accidentally close the gap between the support ring 45 and the suspension head 1.

[0045] Furthermore, the excitation ring 44 includes an annular body 442 and a plurality of claws 443 connected to the top of the annular body 442, the top ends of the plurality of claws 443 are provided with inwardly protruding flanges 444, the inner side surfaces of the plurality of claws 443 are provided with second limiting protrusions 445, and a fourth groove 34 is provided on the outer peripheral surface of the casing hanger 3 corresponding to the second limiting protrusion 445, and when the sealing assembly 4 is in a sealing state, the second limiting protrusion 445 and the fourth groove 34 are clamped and matched.

[0046] As can be seen from the above description, the second limiting protrusion 445 and the fourth clamping groove 34 can limit the relative position of the excitation ring 44 and the casing hanger 3 in the axial direction, so that the sealing assembly 4 is kept in a sealed state. When the sealing assembly 4 needs to be recovered, the recovery tool is inserted into the inner side of the excitation ring 44, and the recovery tool squeezes the multiple claws 443 to open the multiple claws 443. At this time, the second limiting protrusion 445 and the fourth clamping groove 34 are separated, and the axial limit of the excitation ring 44 and the casing hanger 3 is released. Then, the recovery tool is lifted up, and the sealing assembly 4 can be pulled out through the flange 444.

[0047] Furthermore, the sealing assembly 4 also includes a pin shaft 47, which is installed on the excitation ring 44. The outer peripheral surface of the support ring 45 is provided with a long groove 452 that slidably cooperates with the pin shaft 47, and the length direction of the long groove 452 is vertically arranged.

[0048] As can be seen from the above description, the cooperation between the pin 47 and the long slot 452 can guide the relative movement of the excitation ring 44 and the support ring 45, and enable the recovery tool to pull out the excitation ring 44 and the support ring 45 together.

[0049] Furthermore, a second annular groove 453 is provided on the inner circumferential surface of the movable component, and the sealing ring 43 is disposed in the second annular groove 453 .

[0050] It can be seen from the above description that the second annular groove 453 is used to limit the position of the sealing ring 43 to prevent the sealing ring 43 from being separated from the movable component.

[0051] Furthermore, the first limiting protrusion 31 is disposed on the limiting shoulder 33 .

[0052] It can be seen from the above description that arranging the first limiting protrusion 31 on the limiting shoulder 33 can reduce the thickness of the carrying ring 2, thereby reducing the production cost and assembly difficulty.

[0053] Furthermore, a return groove 35 is provided on the limit shoulder 33, and the return groove 35 connects the top surface and the bottom surface of the limit shoulder 33; a return hole 36 is opened on the casing hanger 3, and the return hole 36 connects the outer circumference and the inner circumference of the casing hanger 3, and when the sealing assembly 4 is in the sent-in state, the outer opening of the return hole 36 is located below the sealing assembly 4, and when the sealing assembly 4 is in the sealed state, the sealing assembly 4 covers the outer opening of the return hole 36.

[0054] From the above description, it can be seen that during the delivery of the auxiliary suspension device, the well fluid at the bottom can return to the upper part of the limit shoulder 33 through the reflux groove 35, and then flow out from the inside of the casing hanger 3 through the reflux hole 36. The setting of the reflux groove 35 and the reflux hole 36 ensures the smooth reflux of the well fluid without affecting the sealing operation of the sealing assembly 4.

[0055] Please refer to Figures 1 to 11 Embodiment 1 of the utility model is: an auxiliary suspension device for a complex wellbore structure, comprising a suspension head 1, a load ring 2, a casing hanger 3 and a sealing assembly 4; a first groove 11 cooperating with the load ring 2 is provided on the inner circumference of the suspension head 1, a second groove 21 is provided on the inner circumference of the load ring 2, a first limiting protrusion 31 cooperating with the second groove 21 is provided on the outer circumference of the casing hanger 3, and a third groove 32 cooperating with a running tool is provided on the inner circumference of the casing hanger 3; the sealing assembly 4 is sleeved between the casing hanger 3 and the suspension head 1, a limiting shoulder 33 is provided on the outer circumference of the casing hanger 3 corresponding to the sealing assembly 4, and the sealing assembly 4 has a running state away from the limiting shoulder 33 and a sealing state against the limiting shoulder 33.

[0056] Specifically, the suspension head 1 and the casing hanger 3 are both in annular shape, the bearing ring 2 is in an open annular shape, and the central axes of the suspension head 1, the casing hanger 3 and the bearing ring 2 are arranged in a colinear manner. The first card slot 11 and the third card slot 32 are both annular grooves, and the second card slot 21 is an arc groove. The number of the first card slot 11, the second card slot 21 and the third card slot 32 is multiple. Figure 4As shown, the axial section of the first slot 11 is a right-angled trapezoid, the width of the first slot 11 gradually decreases from one side close to the inner circumference of the suspension head 1 to the other side, the top surface of the first slot 11 is parallel to the horizontal plane, and the bottom surface of the first slot 11 is a conical surface. A trapezoidal protrusion matching the first slot 11 is provided on the outer circumference of the load ring 2. The axial section of the second slot 21 is an isosceles trapezoid, and the width of the second slot 21 gradually decreases from one side close to the casing hanger 3 to the other side. The first limiting protrusion 31 is annular, and the axial section of the first limiting protrusion 31 is set to an isosceles trapezoid corresponding to the second slot 21. When the casing hanger 3 is lowered into the inner cavity of the suspension head 1 until it is hung on the load ring 2 inside the suspension head 1, the load ring 2 will shrink inward under the action of the bottom surface of the first slot 11 so that the second slot 21 is clamped and matched with the first limiting protrusion 31, thereby limiting the relative position of the casing hanger 3 and the suspension head 1 in the axial direction. The provision of multiple first slots 11 and multiple second slots 21 can respectively increase the contact area between the load-bearing ring 2 and the suspension head 1 and between the load-bearing ring 2 and the casing hanger 3, which not only ensures a larger inner diameter but also meets the load-bearing requirements, and has high applicability. The axial cross-section of the third slot 32 is an isosceles trapezoid. The limit shoulder 33 is arc-shaped, and the axial cross-section of the limit shoulder 33 is a right-angle trapezoid. The width of the limit shoulder 33 gradually decreases from one side close to the outer peripheral surface of the casing hanger 3 to the other side. The top surface of the limit shoulder 33 is parallel to the horizontal plane, and the bottom surface of the limit shoulder 33 is a conical surface. In order to reduce the thickness of the load-bearing ring 2, thereby reducing the production cost and assembly difficulty, the first limit protrusion 31 is provided on the limit shoulder 33.

[0057] like Figure 2 As shown, a return groove 35 is provided on the limiting shoulder 33, and the return groove 35 connects the top surface and the bottom surface of the limiting shoulder 33; Figure 2 and Fig.10 As shown, a return hole 36 is provided on the casing hanger 3, and the return hole 36 communicates the outer circumference and the inner circumference of the casing hanger 3. When the sealing assembly 4 is in the delivery state, the outer opening of the return hole 36 is located below the sealing assembly 4. When the sealing assembly 4 is in the sealing state, the sealing assembly 4 covers the outer opening of the return hole 36. Specifically, there are multiple return grooves 35 and multiple return holes 36. The multiple return grooves 35 are evenly distributed around the axial direction of the casing hanger 3, and the multiple return holes 36 are evenly distributed around the axial direction of the casing hanger 3. A return hole 36 is respectively provided directly above each return groove 35. The inner opening of the return hole 36 is located above the outer opening of the return hole 36.

[0058] like Figure 5As shown, the sealing assembly 4 is also provided with a first breakable screw 41, and the outer circumferential surface of the casing hanger 3 is provided with a first limiting hole that cooperates with the first breakable screw 41, and the first breakable screw 41 is used to keep the sealing assembly 4 in the inserted state. Specifically, there are multiple first breakable screws 41, and the multiple first breakable screws 41 are evenly distributed around the circumference of the casing hanger 3. The axial direction of the first breakable screw 41 is perpendicular to the axial direction of the casing hanger 3. The external tool drives the excitation ring 44 downward, so that the first breakable screw 41 is sheared by force, and the external tool is able to push the entire sealing assembly 4 to move downward along the outer wall surface of the casing hanger 3 through the excitation ring 44 until the sealing assembly 4 reaches a sealing state that abuts against the limiting shoulder 33.

[0059] like Figure 5 As shown, the sealing assembly 4 includes a movable component, an elastic rubber tube 42 and a sealing ring 43, and the elastic rubber tube 42 and the sealing ring 43 are both in annular shape. The elastic rubber tube 42 is arranged on the outer periphery of the movable component, and a second annular groove 453 is arranged on the inner circumference of the movable component, and the sealing ring 43 is arranged in the second annular groove 453. The elastic rubber tube 42 is used to close the gap between the movable component and the suspension head 1, and the sealing ring 43 is used to close the gap between the movable component and the casing hanger 3.

[0060] Specifically, Figure 5 and Figure 7 As shown, the sealing ring 43 is O-shaped, and the second annular groove 453 is a dovetail groove. The movable assembly includes an excitation ring 44 and a support ring 45, both of which are annular. The support ring 45 is sleeved on the outer periphery of the casing hanger 3, and the excitation ring 44 is sleeved on the outer periphery of the support ring 45. The excitation ring 44 is located above the support ring 45. When the sealing assembly 4 is in a sealed state, the bottom surface of the support ring 45 abuts against the top surface of the limiting shoulder 33. The excitation ring 44, the support ring 45, the elastic rubber tube 42, the sealing ring 43 and the casing hanger 3 are arranged in the same axis. A receiving groove 451 is provided on the outer peripheral surface of the support ring 45, and the elastic rubber tube 42 is arranged in the receiving groove 451. The second annular groove 453 is provided on the inner peripheral surface of the support ring 45. The top surface of the elastic rubber tube 42 is provided with a first annular groove 421, and the bottom end of the excitation ring 44 is provided with a convex ring 441 for inserting into the first annular groove 421. The thickness of the convex ring 441 is greater than the width of the first annular groove 421 , so that after the convex ring 441 is inserted into the first annular groove 421 , the elastic rubber tube 42 is pressed against the inner wall surface of the suspension head 1 and the outer wall surface of the support ring 45 by the convex ring 441 .

[0061] like Fig.12As shown, the seal assembly 4 also includes a pin 47, which is mounted on the excitation ring 44. A long groove 452 is provided on the outer circumferential surface of the support ring 45 to slide with the pin 47, and the length direction of the long groove 452 is vertically arranged. Specifically, there are multiple pins 47, and the multiple pins 47 are evenly distributed around the axial direction of the excitation ring 44. The number of pins 47 and the number of long grooves 452 are arranged one by one. The long groove 452 is oblong. The cooperation between the pin 47 and the long groove 452 can guide the relative movement of the excitation ring 44 and the support ring 45.

[0062] like Fig.10 As shown, the movable assembly further includes a second breakable screw 46, which is used to lock the relative positions of the excitation ring 44 and the support ring 45 so that the convex ring 441 is kept at a position away from the elastic rubber tube 42. Specifically, there are multiple second breakable screws 46, and the multiple second breakable screws 46 are evenly distributed around the axial direction of the excitation ring 44. The axial direction of the second breakable screw 46 is perpendicular to the axial direction of the casing hanger 3. The excitation ring 44 is provided with a through hole for the second breakable screw 46 to pass through, and the support ring 45 is provided with a threaded hole that cooperates with the second breakable screw 46. When the sealing assembly 4 moves downward under the drive of external force until the support ring 45 contacts the limit shoulder 33, the excitation ring 44 cuts off the second breakable screw 46 under the further drive of the external load, and then continues to move downward, so that the convex ring 441 enters the first ring groove 421 of the elastic rubber tube 42. The elastic rubber tube 42 will press the inner wall surface of the suspension head 1 and the outer wall surface of the support ring 45 respectively under the extrusion of the convex ring 441, thereby closing the gap between the support ring 45 and the suspension head 1.

[0063] like Figure 2 and Figure 8As shown, the excitation ring 44 includes an annular body 442 and a plurality of claws 443 connected to the upper part of the annular body 442. The top ends of the plurality of claws 443 are provided with flanges 444 protruding inwardly. The inner side surfaces of the plurality of claws 443 are provided with second limiting protrusions 445. The outer peripheral surface of the casing hanger 3 is provided with a fourth clamping groove 34 corresponding to the second limiting protrusion 445. When the sealing assembly 4 is in a sealing state, the second limiting protrusion 445 and the fourth clamping groove 34 are clamped and matched. Specifically, the flange 444 is used to clamp with the recovery tool. The fourth clamping groove 34 is annular, and the axial section of the fourth clamping groove 34 is a right-angled trapezoid. The width of the fourth clamping groove 34 gradually decreases from one side close to the outer peripheral surface of the casing hanger 3 to the other side. The top surface of the fourth clamping groove 34 is parallel to the horizontal plane, and the bottom surface of the fourth clamping groove 34 is a conical surface. The second limiting protrusion 445 is arc-shaped, and the axial cross-section of the second limiting protrusion 445 is set to a right triangle or a right trapezoid corresponding to the fourth clamping groove 34. The second limiting protrusion 445 and the fourth clamping groove 34 can limit the relative position of the excitation ring 44 and the casing hanger 3 in the axial direction, so that the sealing assembly 4 remains in a sealed state. When it is necessary to recover the sealing assembly 4, the recovery tool is inserted into the inner side of the excitation ring 44. Since the outer diameter of the recovery tool is larger than the inner diameter of the excitation ring 44, the recovery tool will open the multiple claws 443 to release the axial limit of the excitation ring 44 and the casing hanger 3. Then, the recovery tool is lifted up to pull out the sealing assembly 4 through the flange 444.

[0064] The working principle of an auxiliary suspension device for a complex wellbore structure according to the first embodiment of the utility model is briefly described as follows: when the casing hanger 3 is lowered into the inner cavity of the suspension head 1 until it is seated on the load-bearing ring 2 inside the suspension head 1, the load-bearing ring 2 will shrink inwardly under the action of the bottom surface of the first clamping groove 11 so that the second clamping groove 21 is clamped and matched with the first limiting protrusion 31, thereby limiting the relative position of the casing hanger 3 and the suspension head 1 in the axial direction; the delivery tool is clamped and matched with the third clamping groove 32 of the casing hanger 3; after the casing hanger and the sealing assembly are delivered into the auxiliary suspension head, the external tool continues to drive the excitation ring 44 downward so that the first breakable screw 41 is sheared by force, and the external tool is able to push the entire sealing assembly 4 to move downward along the outer wall surface of the casing hanger 3 through the excitation ring 44; when the sealing assembly 4 moves downward under the drive of the external force until the support ring 45 contacts the limiting shoulder 33, the excitation ring 44 shears the second breakable screw 46 under the further drive of the external load, and then continues to move downward The convex ring 441 moves so that the convex ring 441 enters the first ring groove 421 of the elastic rubber tube 42. The elastic rubber tube 42 will press the inner wall surface of the suspension head 1 and the outer wall surface of the support ring 45 respectively under the extrusion of the convex ring 441, thereby closing the gap between the support ring 45 and the suspension head 1. At this time, the sealing ring 43 closes the gap between the support ring 45 and the casing hanger 3, and the sealing assembly 4 is in a sealed state. The second limiting protrusion 445 of the excitation ring 44 and the fourth groove 34 of the casing hanger 3 are engaged with each other to limit the excitation ring 4 4 and the casing hanger 3 in the axial direction, so that the sealing assembly 4 can be maintained in a sealed state; when the sealing assembly 4 needs to be recovered, the recovery tool is inserted into the inner side of the excitation ring 44. Since the outer diameter of the recovery tool is larger than the inner diameter of the excitation ring 44, the recovery tool will cause the multiple claws 443 to open. At this time, the second limiting protrusion 445 and the fourth groove 34 are separated, and the axial limiting of the excitation ring 44 and the casing hanger 3 is released. The recovery tool is lifted up, and the sealing assembly 4 can be pulled out through the flange 444.

[0065] In summary, the suspension head of the auxiliary suspension device for complex wellbore structures provided by the utility model is directly or indirectly connected to the bottom of the underwater wellhead through the casing. By lowering the casing hanger into the inner cavity of the suspension head so that it sits on the bearing ring inside the suspension head, the need to increase the casing layer can be met without replacing the existing underwater wellhead device; by shrinking the bearing ring to increase the contact area with the casing hanger, a larger inner diameter is ensured and the bearing requirements are met, which has high applicability. The sealing assembly in the inner cavity of the auxiliary suspension device can close the gap between the casing hanger and the suspension head to prevent well fluid leakage. The well fluid at the bottom can return to the upper part of the limit shoulder through the reflux groove, and then flow out from the inside of the casing hanger through the reflux hole. The setting of the reflux groove and the reflux hole ensures the smooth reflux of the well fluid without affecting the sealing operation of the sealing assembly.

[0066] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. An auxiliary suspension device for a complex wellbore structure, characterized in that: The invention comprises a suspension head, a load ring, a casing hanger and a sealing assembly; the inner circumference of the suspension head is provided with a first groove matched with the load ring, the inner circumference of the load ring is provided with a second groove, the outer circumference of the casing hanger is provided with a first limiting protrusion matched with the second groove, and the inner circumference of the casing hanger is provided with a third groove matched with the running tool; The sealing assembly is sleeved between the casing hanger and the hanging head. A limiting shoulder is provided on the outer circumferential surface of the casing hanger corresponding to the sealing assembly. The sealing assembly has a feeding state away from the limiting shoulder and a sealing state against the limiting shoulder.

2. The auxiliary suspension device for a complex wellbore structure according to claim 1, characterized in that: The sealing assembly is also provided with a first breakable screw, and the outer peripheral surface of the casing hanger is provided with a first limiting hole matched with the first breakable screw, and the first breakable screw is used to keep the sealing assembly in the sent-in state.

3. The auxiliary suspension device for a complex wellbore structure according to claim 1, characterized in that: The sealing assembly comprises a movable component, an elastic rubber tube and a sealing ring; the elastic rubber tube is arranged on the outer periphery of the movable component, and the sealing ring is arranged on the inner periphery of the movable component.

4. The auxiliary suspension device for a complex wellbore structure according to claim 3, characterized in that: The movable component includes an excitation ring and a support ring. The excitation ring is sleeved on the outer circumference of the support ring. A receiving groove is provided on the outer circumference of the support ring. The elastic rubber tube is arranged in the receiving groove. A first ring groove is opened on the top surface of the elastic rubber tube. The bottom end of the excitation ring is provided with a convex ring for inserting into the first ring groove.

5. The auxiliary suspension device for a complex wellbore structure according to claim 4, characterized in that: The movable assembly further comprises a second breakable screw, which is used to lock the relative positions of the excitation ring and the support ring so as to keep the convex ring at a position away from the elastic rubber cylinder.

6. The auxiliary suspension device for a complex wellbore structure according to claim 4, characterized in that: The excitation ring includes an annular body and a plurality of claws connected to the top of the annular body, the top ends of the plurality of claws are provided with inwardly protruding flanges, the inner side surfaces of the plurality of claws are provided with second limiting protrusions, and a fourth groove is provided on the outer peripheral surface of the casing hanger corresponding to the second limiting protrusion. When the sealing assembly is in a sealing state, the second limiting protrusion and the fourth groove are clamped and matched.

7. The auxiliary suspension device for a complex wellbore structure according to claim 6, characterized in that: The sealing assembly also includes a pin shaft, which is installed on the excitation ring. A long groove that slidably cooperates with the pin shaft is provided on the outer peripheral surface of the support ring, and the length direction of the long groove is vertically arranged.

8. The auxiliary suspension device for a complex wellbore structure according to claim 3, characterized in that: A second annular groove is provided on the inner circumferential surface of the movable component, and the sealing ring is arranged in the second annular groove.

9. The auxiliary suspension device for a complex wellbore structure according to claim 1, characterized in that: The first limiting protrusion is arranged on the limiting shoulder.

10. The auxiliary suspension device for a complex wellbore structure according to claim 1, characterized in that: A reflux groove is provided on the limit shoulder, and the reflux groove connects the top surface and the bottom surface of the limit shoulder; a reflux hole is opened on the casing hanger, and the reflux hole connects the outer circumference and the inner circumference of the casing hanger. When the sealing assembly is in the sent-in state, the outer opening of the reflux hole is located below the sealing assembly. When the sealing assembly is in the sealing state, the sealing assembly covers the outer opening of the reflux hole.

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