Integrated subsea oil production wellhead device

Abstract

The invention discloses an integrated underwater oil extraction wellhead device, relates to the technical field of underwater oil and gas extraction engineering, and solves the problem that a well slot of a water injection device and a well slot of an oil extraction device are tight. A casing hanger A; a casing hanger B; the inner side of the oil pipe hanger is provided with a vertically-through cavity, and at least one blanking plug is placed in the cavity; a sealing cover; an underwater hydraulic gate valve; the side wall of the high-pressure wellhead body and the side wall of the oil pipe hanger are provided with oil outlet holes used for communicating the underwater hydraulic gate valve with the cavity, and a sealing structure is arranged between the outer wall of the oil pipe hanger and the inner wall of the high-pressure wellhead body. The integral function and the operation process of the oil extraction device are optimized, the integrated underwater oil extraction wellhead device which is simple and reliable in structure and more convenient to use is formed, the economical underwater oil extraction requirement is met, and the problem that oil extraction device well grooves are tight is solved.

Description

Technical Field

[0001] The invention relates to the technical field of underwater oil and natural gas production engineering, in particular to an integrated underwater oil production wellhead device. Background Art

[0002] In the process of oil and gas extraction, especially the extraction of submarine oil, it is necessary to first drill a well on the seabed and then install the extraction equipment for extraction. Conventional underwater Christmas trees are large in size and weight, complex to install and operate, extremely costly, and inconvenient to maintain.

[0003] Since most of the existing oil fields are produced by oil production platforms, this production method affects the navigation of surface ships and the operation of fishermen, and the cost of building drilling platforms is also quite huge. In order to solve this dilemma, offshore oil fields are in urgent need of an underwater oil production method that will not affect the waterway, but also meet the needs of fishermen's operations, and most importantly, reduce development costs when the demand is large. This demand is particularly urgent in offshore areas such as the Bohai Oilfield area. Summary of the invention

[0004] The purpose of the present invention is to solve the above problems and to design an integrated underwater oil production wellhead device. This underwater oil production system is suitable for underwater oil production in shallow water areas, solving the problem of large oil production demand but high production cost.

[0005] The technical solution of the present invention to achieve the above-mentioned purpose is an integrated underwater oil production wellhead device, comprising: A high-pressure wellhead body, wherein the inner side of the high-pressure wellhead body has an accommodating cavity that passes through from top to bottom; A casing hanger A, wherein the casing hanger A is hung in the accommodating cavity, and the lower end of the casing hanger A is connected to the casing A; A casing hanger B, the casing hanger B is located above the casing hanger A and is hung in the accommodating cavity, the lower end of the casing hanger B is connected to a casing B, and the casing B passes through the casing hanger A and the casing A in sequence; A tubing hanger, the tubing hanger is located above the casing hanger B and is hung in the accommodating cavity, the lower end of the tubing hanger is connected to the tubing, the tubing hanger passes through the casing hanger B and the casing B in sequence, the inner side of the tubing hanger has a cavity that passes through from top to bottom, and at least one plug is placed in the cavity for isolating the cavity from the external space of the tubing hanger; A Christmas tree cap, which is mounted and fixed on the top of the high-pressure wellhead body; An underwater hydraulic gate valve, wherein the underwater hydraulic gate valve is installed on the high-pressure wellhead body; The side walls of the high-pressure wellhead body and the oil pipe hanger are provided with an oil outlet hole for connecting the underwater hydraulic gate valve with the cavity, and the oil outlet hole is located below the plug. The outer wall of the oil pipe hanger and the inner wall of the high-pressure wellhead body are provided with sealing structures on both sides above the oil outlet hole.

[0006] Furthermore, a groove is provided on the inner wall of the accommodating cavity, a locking ring is fixedly installed on the outer side of the casing hanger A, and a clamping block that can be opened and closed is provided on the locking ring. A spacer ring A is threadedly connected to the outer side of the casing hanger A, and the lower side of the spacer ring A is matched with the clamping block in an inclined surface to control the clamping block to expand outward and clamp with the groove.

[0007] Furthermore, a locking ring is fixedly installed on the outer side of the casing hanger B, and the locking ring has a clamping block that can be opened and closed. The outer side of the casing hanger B is threadedly connected to a spacer ring B, and the lower side of the spacer ring B is matched with the clamping block in an inclined surface to control the clamping block to expand outward and clamp with the slot.

[0008] Furthermore, a rubber sealing ring is provided between the spacer ring A and the casing hanger A and the high-pressure wellhead body, and a metal sealing ring is provided between the spacer ring B and the casing hanger B and the high-pressure wellhead body. The metal sealing ring is clamped with the spacer ring B and is tightly attached to the inner wall of the high-pressure wellhead body.

[0009] Furthermore, the sealing structure includes a metal seal, an extrusion piece and a rubber seal. The metal seal has an extrusion groove with a conical cross-section. The two side surfaces of the extrusion piece are inclined with the extrusion groove. The rubber seal is arranged between the metal seal and the oil pipe hanger and between the metal seal and the high-pressure wellhead body. The two sides of the metal seal protrude outward to form a sealing portion.

[0010] Furthermore, a hook is provided at the bottom of the Christmas tree cap, the Christmas tree cap is fixed to the high-pressure wellhead body via a connecting device, and a plugging head is installed at the oil outlet of the underwater hydraulic gate valve.

[0011] Furthermore, a rubber sealing ring is provided between the Christmas tree cap and the inner wall of the wellhead body, and a lifting lug is welded on the top of the Christmas tree cap.

[0012] Furthermore, it also includes a base, the base has a connecting sleeve, and the high-pressure wellhead body is fixedly connected to the connecting sleeve through a flange.

[0013] Furthermore, a mechanical compass and an anode block are installed on the base, and a protective net for covering the base and the high-pressure wellhead body is arranged on the outer side of the base.

[0014] Furthermore, a guide cylinder is welded on the base, and a guide rod is inserted and connected in the guide cylinder.

[0015] Compared with the prior art, the beneficial effects are: The present invention optimizes the overall function and operation process of the underwater oil production device, forming a set of integrated underwater oil production wellhead devices with simple and reliable structure and more convenient use, which meets the needs of economical underwater oil production. The underwater oil production wellhead device controls the opening and closing of the waterway through the underwater hydraulic gate valve, and is connected with the inner cavity of the oil pipe hanger through the oil outlet. The upper side of the inner cavity of the oil pipe hanger is isolated from the external pressure by a plug. During the oil production operation, the underwater hydraulic gate valve is opened to output oil from the oil pipe, and is transported to the shore oil depot or ship through the pipeline. This oil production wellhead device has a simple and reliable structure and is easy to use. It does not occupy the waterway and does not affect the operation of fishermen. In particular, sealing structures are provided on the upper and lower sides of the oil outlet. The sealing structure activates the seal by self-extrusion. The design is simple and reliable, and the installation is convenient. It greatly reduces the difficulty of blind operation of underwater installation, and at the same time reduces the loss rate of the seal during the installation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the integrated underwater oil production wellhead device of the present invention; Figure 2 It is a schematic diagram of the structure of the integrated underwater oil production wellhead device when the high-pressure wellhead body is removed; Figure 3 It is a schematic diagram of the cross-sectional structure of an integrated underwater oil production wellhead device; Figure 4 yes Figure 3 A magnified view of the structure at center A; Figure 5 It is a structural schematic diagram of a Christmas tree cap and its accessory structures; Figure 6 1 is a schematic diagram of the bottom structure of the Christmas tree cap; Figure 7 It is a schematic diagram of the axial cross-sectional structure of the integrated underwater oil production wellhead device when the guide rod is removed; Figure 8 It is a cross-sectional plan view of the integrated underwater oil production wellhead device when the guide rod is removed; Fig. 9 yes Figure 8 A magnified view of the structure at B in the middle; Fig.10 yes Figure 8 A magnified view of the structure at C in the middle; Fig.11 yes Figure 8 A magnified view of the structure at D in the middle; Fig.12 yes Fig.11Enlarged view of the structure at E in the middle.

[0017] In the figure, 1, base; 101, connecting sleeve; 102, guide cylinder; 2, high-pressure wellhead body; 3, Christmas tree cap; 4, guide rod; 5, anode block; 6, underwater hydraulic gate valve; 7, plugging head; 8, mechanical compass; 9, casing hanger B; 10, tubing hanger; 1001, cavity; 1002, oil outlet; 11, casing hanger A; 12, spacer ring A; 13, spacer ring B; 14, casing A; 15, casing B; 16, tubing; 1 7. Plug; 18. Protective net; 19. Rubber sealing ring; 20. Lifting ear; 21. Sealing plug; 22. Connecting device; 221. Positioning pin; 23. Pipeline joint; 24. Limiting ring; 25. Hook; 26. Sealing structure; 261. Metal seal; 2611. Sealing part; 262. Extrusion piece; 263. Rubber seal; 27. Locking ring; 28. Metal sealing ring; 29. ​​Excitation ring; 30. Fixing ring; 31. Limiting ring. DETAILED DESCRIPTION

[0018] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] like Figure 1-Figure 8 As shown, a preferred embodiment of the present invention proposes an integrated underwater oil production wellhead device, and the oil production system mainly includes: a high-pressure wellhead body 2, a casing hanger A11, a casing hanger B9, a tubing hanger 10, a base 1, an underwater hydraulic gate valve 6, a spacer ring A12, a spacer ring B13, a mechanical compass 8, an anode block 5, an oil tree cap 3, etc.

[0020] refer to Figure 1 A connecting sleeve 101 is welded on the base 1, and the lower end of the high-pressure wellhead body 2 is fixedly connected to the connecting sleeve 101 through a flange. The high-pressure wellhead body 2 is cylindrical in shape, and has a receiving cavity for accommodating the hanger. In the receiving cavity inside the high-pressure wellhead body 2, the casing hanger A11, the spacer ring A12, the casing hanger B9, the spacer ring B13, the tubing hanger 10 and the Christmas tree cap 3 are sequentially hung from bottom to top.

[0021] like Figure 3 As shown, three slots are provided from top to bottom on the inner wall of the accommodating cavity, which correspond to the casing hanger A11, casing hanger B9 and tubing hanger 10. Locking rings 27 are installed on the outer sides of the casing hanger A11, casing hanger B9 and tubing hanger 10, and the circumference of the locking block has a plurality of clamping blocks that can be opened and closed, and the clamping blocks have a certain elasticity.

[0022] The spacer ring A12 is installed on the casing hanger A11 and fixed thereto by threaded engagement. During the installation process, the spacer ring A12 can activate the locking ring 27 on the casing hanger A11. The lower side of the spacer ring A12 is inserted into the gap between the locking ring 27 and the casing hanger A11, and cooperates with the inclined surface of the clamping block on the locking ring 27 to squeeze the clamping block, so that the clamping block opens outward and engages with the clamping groove on the inner wall of the high-pressure wellhead body 2, thereby fixing the casing hanger A11 and the high-pressure wellhead body 2 together.

[0023] A rubber sealing ring is provided between the spacer ring A12, the casing hanger A11 and the high-pressure wellhead body 2 to seal the pressure from the well or the annulus.

[0024] The structure of the spacer ring B13 is the same as that of the spacer ring A12. The spacer ring B13 is installed on the casing hanger B9 and fixed to it by threaded fitting. In the same principle, the spacer ring B13 can stimulate the locking ring 27 on the casing hanger B9 during the installation process, and the lower side of the spacer ring B13 is inserted into the gap between the locking ring 27 and the casing hanger B9, and cooperates with the inclined surface of the clamping block on the locking ring 27, squeezing the clamping block so that the clamping block opens outward and engages with the clamping groove on the inner wall of the high-pressure wellhead body 2, so that the casing hanger B9 is fixed to the high-pressure wellhead body 2, and at the same time, the casing hanger B9 is hung on the top of the casing hanger A11.

[0025] refer to Fig.10 A metal sealing ring 28 is arranged between the spacer ring B13, the casing hanger B9 and the high-pressure wellhead body 2. The cross-sectional shape of the metal sealing ring 28 is similar to an H shape. The metal sealing ring 28 is located in the groove outside the spacer ring B13 and has an interference fit with the inner wall of the high-pressure wellhead body 2, which has stronger sealing performance and can seal the pressure from the well or the annulus.

[0026] The lower end of the casing hanger A11 is threadedly connected with a casing A14, and the casing A14 extends downwardly. The lower end of the casing hanger B9 is threadedly connected with a casing B15, and the casing B15 passes through the casing hanger A11 and the casing A14.

[0027] refer to Fig. 9A fixing ring 30, a stop ring 24, a stop ring 31 and an excitation ring 29 are arranged on the outside of the tubing hanger 10. The specific cooperation between these components and the locking ring 27 can be referred to the hanger recovery tool with the publication number CN118442016A. The above structure can be set up through the tool to quickly complete the installation and recovery of the tubing hanger 10. After the locking ring 27 on the tubing hanger 10 is activated, it will be engaged with the card groove on the inner wall of the high-pressure wellhead body 2, so that the tubing hanger 10 is fixed together with the high-pressure wellhead body 2. The locking system structure is reliable, stable and easy to install.

[0028] like Figure 7 , Figure 8 As shown, the inner side of the tubing hanger 10 has a cavity 1001 that passes through from top to bottom. A tubing 16 is threadedly connected to the lower end of the tubing hanger 10. The tubing 16 is connected to the cavity 1001. The tubing 16 passes through the casing hanger B9, casing B15, casing hanger A11, casing A14, and extends downward.

[0029] like Figure 7 As shown, the underwater hydraulic gate valve 6 is installed on the outside of the high-pressure wellhead body 2. The valve is hydraulically controlled and matches the forced opening interface in the API 17H standard. Oil can be produced through this valve during oil production operations. The valve controls the opening and closing of the water production oil circuit.

[0030] like Fig.11 As shown, an oil outlet hole 1002 is provided on the side of the high-pressure wellhead body 2 and the tubing hanger 10, which is used to connect the underwater hydraulic gate valve 6 and the cavity 1001 inside the tubing hanger 10. A sealing structure 26 is provided at the lower part between the tubing hanger 10 and the wellhead outer shell, and the sealing structure 26 is located on the upper and lower sides of the oil outlet hole 1002 to ensure sealing. The sealing structure 26 includes two sealing forms, namely, rubber sealing and metal sealing, which have reliable sealing, high pressure bearing capacity, good corrosion resistance, long service life and high stability.

[0031] like Fig.11 , Fig.12As shown, the above-mentioned sealing structure 26 is mainly composed of a metal seal 261, an extrusion piece 262 and a rubber seal 263. The three parts are all annular structures, wherein an extrusion groove is provided on the metal seal 261, and the two inner side walls of the extrusion groove are both inclined surfaces, and the two outer side walls of the extrusion piece 262 are also inclined surfaces. After the extrusion piece 262 is inserted into the extrusion groove, it cooperates with its inclined surface to squeeze the two side walls of the extrusion groove outward, and the two outer side walls of the metal seal 261 protrude outward to form a sealing portion 2611. When the extrusion piece 262 squeezes the metal seal 261, the sealing portion 2611 will be tightly attached to the inner wall of the high-pressure wellhead body 2 and the outer wall of the oil pipe hanger 10, thereby playing a sealing role. A rubber seal 263 is provided between the metal seal 261 and the tubing hanger 10 and between the metal seal 261 and the high-pressure wellhead body 2. The rubber seal 263 also protrudes outward to form a sealing portion 2611, which is also an extrusion-activated seal.

[0032] Both forms of seals are activated by self-extrusion. External pressure will squeeze the extrusion piece 262, thereby activating the metal seal 261 and the rubber seal 263. The greater the extrusion force, the stronger the sealing. The structural design is simple and reliable, easy to install, greatly reducing the difficulty of blind operation of underwater installation, and at the same time reducing the loss rate of seals during installation.

[0033] refer to Fig. 9 A sealing structure 26 is also provided on the upper part of the tubing hanger 10 , and the sealing form is the same as that of the lower part. The sealing structure 26 is located on the lower side of the locking ring 27 on the tubing hanger 10 .

[0034] like Figure 1 , Figure 5 As shown, the Christmas tree cap 3 is installed on the top of the high-pressure wellhead body 2 and is fixed to the high-pressure wellhead body 2 via a connecting device 22. At the same time, a rubber sealing ring 19 is used to seal between the Christmas tree cap 3 and the high-pressure wellhead body 2 to prevent seawater and marine organisms from entering the high-pressure wellhead body 2.

[0035] refer to Figure 6 The Christmas tree cap 3 is composed of a sealing plug 21 and a connecting device 22, wherein a hook 25 is designed at the bottom of the sealing plug 21 for hanging the ethylene glycol device. Since there is a certain space between the tubing hanger 10 and the sealing plug 21, the ethylene glycol device is hung on the hook 25. After the ethylene glycol evaporates, corrosion can be prevented, thereby increasing the service life of the device.

[0036] refer to Figure 4 , Figure 6 , Fig. 9A pipeline joint 23 is installed on the sealing plug 21. The bottom of the sealing plug 21 has a positioning pin 221 and a slot for positioning and fixing with the tubing hanger 10 below. The middle of the pipeline joint 23 has a threading hole that passes through the threading hole, so that the pipeline passes through the threading hole and the sealing plug 21, so as to achieve the continuity of the pipeline passing through and constrain and fix the pipeline at the same time.

[0037] A lifting lug 20 is welded on the top of the sealing plug 21 to facilitate lifting of the integrated underwater oil production wellhead device.

[0038] like Figure 1 , Figure 7 As shown, a plugging head 7 is installed at the oil outlet of the underwater hydraulic gate valve 6. The plugging head 7 is fixedly installed on the underwater hydraulic gate valve 6 through a flange. When oil is not produced, the oil outlet of the underwater hydraulic gate valve 6 is blocked by the plugging head 7.

[0039] During oil production, the plugging head 7 is removed and the oil pipeline is connected. Since the upper part of the cavity 1001 inside the oil pipe hanger 10 is through, two plugs 17 need to be placed in the cavity 1001 to isolate the oil production pressure from the external pressure, so that the crude oil cannot flow out from the upper part of the cavity 1001. After the upper part of the cavity 1001 is blocked, the crude oil will flow out to one side along the cavity 1001 and be output to the shore oil tank or oil tank ship through the oil pipe 16.

[0040] The plug 17 is interference fit with the cavity 1001 inside the tubing hanger 10 and is squeezed in by force. It can be taken out by using a special tool.

[0041] When oil is not produced, the underwater hydraulic gate valve 6 is closed, the plug 17 is taken out, and then the Christmas tree cap 3 is removed, and the oil can flow upward along the oil pipe 16.

[0042] refer to Figure 1 , Figure 2 , the anode block 5 and the mechanical compass 8 are both installed on the outside of the base 1, located on the top of the base 1. The anode block 5 is used to slow down the corrosion of seawater, and the mechanical compass 8 is used for leveling when installing the wellhead. At the same time, a protective net 18 is set on the outside of the entire oil production system, and the protective net 18 covers the entire base 1 and the high-pressure wellhead body 2. It is used to cover the base 1 and various structures installed on the base 1 to prevent tugboat fishing nets and falling objects.

[0043] Guide cylinders 102 are welded at multiple positions on the base 1, and guide rods 4 are inserted into the guide cylinders 102. The lower ends of the guide rods 4 are inserted into the seabed, and then when the oil production system is installed below, the guide cylinders 102 slide downward along the guide rods 4. Since seawater has a certain fluidity, the guide rods 4 are used to lower the integrated underwater oil wellhead device to a designated position on the seabed.

[0044] The above technical solutions only reflect the preferred technical solutions of the technical solutions of the present invention. Some changes that may be made to certain parts thereof by technicians in this technical field all reflect the principles of the present invention and fall within the protection scope of the present invention.

Claims

1. An integrated underwater oil production wellhead device, characterized in that: include: A high-pressure wellhead body (2), wherein the inner side of the high-pressure wellhead body (2) has a receiving cavity that passes through from top to bottom; A casing hanger A (11), the casing hanger A (11) is suspended in the accommodating cavity, and the lower end of the casing hanger A (11) is connected to a casing A (14); A casing hanger B (9), the casing hanger B (9) being located above the casing hanger A (11) and hanging in the accommodating cavity, the lower end of the casing hanger B (9) being connected to a casing B (15), the casing B (15) passing through the casing hanger A (11) and the casing A (14) in sequence; A tubing hanger (10), the tubing hanger (10) being located above the casing hanger B (9) and hanging in the accommodating cavity, the lower end of the tubing hanger (10) being connected to an oil pipe (16), the tubing hanger (10) passing through the casing hanger B (9) and the casing B (15) in sequence, the inner side of the tubing hanger (10) being provided with a cavity (1001) passing through from top to bottom, at least one plug (17) being placed in the cavity (1001) for isolating the cavity (1001) from the external space of the tubing hanger (10); A Christmas tree cap (3), the Christmas tree cap (3) being mounted and fixed on the top of the high-pressure wellhead body (2); An underwater hydraulic gate valve (6), wherein the underwater hydraulic gate valve (6) is installed on the high-pressure wellhead body (2); The side walls of the high-pressure wellhead body (2) and the tubing hanger (10) are provided with an oil outlet hole (1002) for connecting the underwater hydraulic gate valve (6) with the cavity (1001); the oil outlet hole (1002) is located below the plug (17); and sealing structures (26) are provided on both sides above the oil outlet hole (1002) between the outer wall of the tubing hanger (10) and the inner wall of the high-pressure wellhead body (2).

2. The integrated underwater oil production wellhead device according to claim 1, characterized in that: The inner wall of the accommodating cavity is provided with a slot, a locking ring (27) is fixedly installed on the outer side of the casing hanger A (11), and the locking ring (27) has a clamping block that can be opened and closed. The outer side of the casing hanger A (11) is threadedly connected with a spacer ring A (12), and the lower side of the spacer ring A (12) and the clamping block are matched with an inclined surface to control the clamping block to expand outward and clamp with the slot.

3. The integrated underwater oil production wellhead device according to claim 2, characterized in that: A locking ring (27) is fixedly installed on the outer side of the casing hanger B (9), and a clamping block that can be opened and closed is provided on the locking ring (27). A spacer ring B (13) is threadedly connected to the outer side of the casing hanger B (9), and the lower side of the spacer ring B (13) is matched with the clamping block in an inclined surface to control the clamping block to expand outward and clamp with the clamping groove.

4. The integrated underwater oil production wellhead device according to claim 3, characterized in that: A rubber sealing ring is provided between the spacer ring A (12), the casing hanger A (11) and the high-pressure wellhead body (2), and a metal sealing ring (28) is provided between the spacer ring B (13), the casing hanger B (9) and the high-pressure wellhead body (2). The metal sealing ring (28) is clamped with the spacer ring B (13) and is tightly attached to the inner wall of the high-pressure wellhead body (2).

5. The integrated underwater oil production wellhead device according to claim 1, characterized in that: The sealing structure (26) comprises a metal seal (261), an extrusion piece (262) and a rubber seal (263); the metal seal (261) is provided with an extrusion groove with a conical cross-section; the two side surfaces of the extrusion piece (262) are inclinedly matched with the extrusion groove; the rubber seal (263) is arranged between the metal seal (261) and the oil pipe hanger (10) and between the metal seal (261) and the high-pressure wellhead body (2); the two sides of the metal seal (261) are protruded outward to form a sealing portion (2611).

6. The integrated underwater oil production wellhead device according to claim 1, characterized in that: A hook (25) is provided at the bottom of the Christmas tree cap (3); the Christmas tree cap (3) and the high-pressure wellhead body (2) are fixed via a connecting device (22); and a plugging head (7) is installed at the oil outlet of the underwater hydraulic gate valve (6).

7. The integrated underwater oil production wellhead device according to claim 6, characterized in that: A rubber sealing ring (19) is arranged between the Christmas tree cap (3) and the inner wall of the wellhead body, and a lifting lug (20) is welded to the top of the Christmas tree cap (3).

8. The integrated underwater oil production wellhead device according to claim 1, characterized in that: It also comprises a base (1), the base (1) having a connecting sleeve (101), and the high-pressure wellhead body (2) is fixedly connected to the connecting sleeve (101) via a flange.

9. The integrated underwater oil production wellhead device according to claim 8, characterized in that: A mechanical compass (8) and an anode block (5) are mounted on the base (1), and a protective net (18) for covering the base (1) and a high-pressure wellhead body (2) is arranged on the outside of the base (1).

10. The integrated underwater oil production wellhead device according to claim 8, characterized in that: A guide cylinder (102) is welded on the base (1), and a guide rod (4) is inserted and connected inside the guide cylinder (102).

Images