CN114876398B - Underwater wellhead assembly for shallow water - Google Patents
Underwater wellhead assembly for shallow water Download PDFInfo
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- CN114876398B CN114876398B CN202210607236.6A CN202210607236A CN114876398B CN 114876398 B CN114876398 B CN 114876398B CN 202210607236 A CN202210607236 A CN 202210607236A CN 114876398 B CN114876398 B CN 114876398B
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- pressure wellhead
- wellhead
- low
- casing hanger
- pressure
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/02—Surface sealing or packing
- E21B33/03—Well heads; Setting-up thereof
- E21B33/035—Well heads; Setting-up thereof specially adapted for underwater installations
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/02—Surface sealing or packing
- E21B33/03—Well heads; Setting-up thereof
- E21B33/035—Well heads; Setting-up thereof specially adapted for underwater installations
- E21B33/038—Connectors used on well heads, e.g. for connecting blow-out preventer and riser
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/02—Surface sealing or packing
- E21B33/03—Well heads; Setting-up thereof
- E21B33/04—Casing heads; Suspending casings or tubings in well heads
- E21B33/043—Casing heads; Suspending casings or tubings in well heads specially adapted for underwater well heads
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- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/02—Surface sealing or packing
- E21B33/03—Well heads; Setting-up thereof
- E21B33/04—Casing heads; Suspending casings or tubings in well heads
- E21B33/047—Casing heads; Suspending casings or tubings in well heads for plural tubing strings
Abstract
The invention discloses an underwater wellhead assembly for shallow water, which comprises a low-pressure wellhead, a high-pressure wellhead, a casing hanger and an annular sealing assembly, wherein the high-pressure wellhead is arranged in the low-pressure wellhead; the casing hanger is arranged in the high-pressure wellhead; the annular sealing assembly is arranged between the casing hanger and the high-pressure wellhead in a sealing manner and is locked between the casing hanger and the high-pressure wellhead. The invention discloses an underwater wellhead assembly for shallow water, which is locked between a casing hanger and a high-pressure wellhead through an annular sealing assembly, has very good sealing performance and locking effect, is simple in tie-back operation, improves the reliability and the operation efficiency of underwater Christmas tree installation, and reduces the difficulty and the uncertainty of the installation.
Description
Technical Field
The invention relates to the technical field of petroleum drilling equipment, in particular to an underwater wellhead assembly for shallow water.
Background
The underwater wellhead is widely applied to deep water oil and gas field development, is used for deep water drilling and completion operation and oil and gas production, is subject to problems of sea contradiction, geopolitical influence and marginal oil fields, and can be used as a mode of limited area oil field development in drilling and oil and gas production in shallow water.
The existing shallow water underwater wellhead device is generally a mud line hanger device, the mud line hanger is arranged below a mud surface, and generally 3-4 layers of casings are connected back to a drilling platform layer by layer to establish a shaft, and the back connection process is complex, low in efficiency and long in time consumption. Wherein, the water depth is generally 300 meters, shallow water is below 300 meters, deep water is 300-1500 meters, and ultra-deep water is more than 1500 meters.
Disclosure of Invention
The invention aims to provide an underwater wellhead assembly for shallow water, which is used for solving the problems of complex tie-back process, low efficiency and long time consumption of a mud line hanger device.
The invention provides an underwater wellhead assembly for shallow water, comprising: a low pressure wellhead; the high-pressure wellhead is arranged in the low-pressure wellhead; a casing hanger positioned within the high pressure wellhead; the annular sealing assembly is arranged between the casing hanger and the high-pressure wellhead in a sealing manner and is locked between the casing hanger and the high-pressure wellhead; the top of the low-pressure wellhead is used for being abutted with a plurality of tie-back pups, the top of the low-pressure wellhead is abutted with the tie-back pups at the lowest position through anticlockwise screwing, the tie-back pups above the tie-back pups at the lowest position are abutted through clockwise screwing, and the lower part of the low-pressure wellhead is connected with a plurality of surface layer conduits.
Preferably, the inner wall of the low-pressure wellhead is provided with an inner step surface of the low-pressure wellhead, the outer wall of the high-pressure wellhead is provided with an outer setting step of the high-pressure wellhead, and when the high-pressure wellhead is arranged inside the low-pressure wellhead, the outer setting step of the high-pressure wellhead is just clamped on the inner step surface of the low-pressure wellhead, so that setting of the high-pressure wellhead in the low-pressure wellhead is completed.
Preferably, a centralizing ring is arranged between the outer wall of the high-pressure wellhead and the inner wall of the low-pressure wellhead, and the centralizing ring is positioned below the outer sitting step of the high-pressure wellhead; when the high-pressure wellhead is placed in the low-pressure wellhead, the centralizing ring can centralize the high-pressure wellhead and maintain the high-pressure wellhead and the low-pressure wellhead in an upright state in a concentric structure.
Preferably, a high-pressure wellhead locking ring is arranged on the outer wall of the high-pressure wellhead between the high-pressure wellhead outer setting step and the centralizing ring, and a sleeve joint groove is arranged on the inner wall of the low-pressure wellhead; when the high-pressure wellhead is pressed down in the low-pressure wellhead, the high-pressure wellhead locking ring is just nested in the sleeving groove of the inner wall of the low-pressure wellhead when the high-pressure wellhead is clamped on the inner step surface of the low-pressure wellhead by the outer sitting and releasing step of the high-pressure wellhead, so that the high-pressure wellhead is locked in the low-pressure wellhead.
Preferably, the inner wall of the high-pressure wellhead is provided with a high-pressure wellhead inner step surface, the outer wall of the casing hanger is provided with a casing hanger lower part setting step, and the casing hanger lower part setting step is matched with the high-pressure wellhead inner step surface; and in the process of lowering the casing hanger into the high-pressure wellhead, the setting step at the lower part of the casing hanger is clamped on the inner step surface of the high-pressure wellhead, so that setting of the casing hanger in the high-pressure wellhead is completed.
Preferably, the outer wall of the casing hanger is provided with a sealing surface, the inner wall of the lower part of the annular sealing assembly is sleeved on the sealing surface of the casing hanger, and the high-pressure wellhead is sleeved on the outer wall of the lower part of the annular sealing assembly.
Preferably, a first sealing groove is formed in the inner wall of the lower part of the annular sealing assembly, an inner metal sealing ring is arranged on the first sealing groove, and the annular sealing assembly and the casing hanger are sealed through the inner metal sealing ring; the outer wall of annulus sealing assembly lower part is provided with the second seal groove, is provided with outer metal seal ring on the second seal groove, seal through outer metal seal ring between annulus sealing assembly and the high-pressure wellhead.
Preferably, the top of the annular sealing assembly is provided with a setting ring, and the bottom end of the outer wall of the setting ring is provided with a sawtooth locking ring; the inner wall of the high-pressure wellhead is provided with a saw tooth slot; when the lower annular ring hollow sealing assembly is inserted into the annular gap between the casing hanger and the high-pressure wellhead, the inner metal sealing ring and the outer metal sealing ring respectively seal the gap between the annular ring sealing assembly and the casing hanger and the gap between the annular ring sealing assembly and the high-pressure wellhead, and meanwhile, the setting ring pushes the saw tooth locking ring downwards to enable the saw tooth locking ring to be nested in the saw tooth groove of the inner wall of the high-pressure wellhead, so that locking of the annular ring sealing assembly between the casing hanger and the high-pressure wellhead is realized.
Compared with the prior art, the invention has the beneficial effects that:
(1) The invention discloses an underwater wellhead assembly for shallow water, which is formed by combining a low-pressure wellhead, a high-pressure wellhead, a casing hanger and an annular sealing assembly, wherein the annular sealing assembly is inserted into an annular gap between the inside of the high-pressure wellhead and the casing hanger, so that the gap between the annular sealing assembly and the casing hanger and the gap between the annular sealing assembly and the high-pressure wellhead are sealed, the casing hanger can be effectively locked by the locking force of the annular sealing assembly, the accuracy of the lowering and installation of the casing hanger is improved, and the risks of wellhead lifting and annular pressure are reduced. The invention discloses an underwater wellhead assembly for shallow water, which is locked between a casing hanger and a high-pressure wellhead through an annular sealing assembly, has very good sealing performance and locking effect, is simple in tie-back operation, improves the reliability and the operation efficiency of underwater Christmas tree installation, and reduces the difficulty and the uncertainty of the installation.
(2) The invention discloses an underwater wellhead assembly for shallow water, which is applied to a self-elevating drilling platform and a ground blowout preventer, wherein the shallow water underwater wellhead assembly is connected with a ground drilling machine and a blowout preventer device, so that the drilling operation of an underwater wellhead is completed by quick drilling, the original operation modes of the semi-submersible drilling platform and the underwater blowout preventer are changed, and an interface is provided for the subsequent installation of an underwater Christmas tree.
(3) The invention discloses an underwater wellhead assembly for shallow water, which is arranged above a mud surface, wherein the top of a low-pressure wellhead is in butt joint with a tie-back nipple, the lower part of the low-pressure wellhead is connected with a plurality of surface conduits, and compared with the existing mud line hanger device which is arranged below the mud surface and adopts a multi-layer sleeve to tie back to a drilling platform layer by layer to establish a shaft, the invention changes the operation mode of the traditional mud line hanger, simplifies the tie-back process, does not need to raise the nipple when carrying out subsequent operation, and solves the problems of long drilling and completion operation period and high cost in the underwater development mode of the oil and gas field in shallow water.
(4) The underwater wellhead assembly for shallow water disclosed by the invention completely changes the original shallow water underwater drilling mode, can save the operation time generated by casing tie-back and backing-off, reduce the operation period of an oil pipe four-way joint when a subsequent underwater Christmas tree is installed, and can greatly save the drilling and completion operation time and cost for oil and gas fields developed by a shallow water underwater production system.
(5) The invention discloses an underwater wellhead assembly for shallow water, wherein a low-pressure wellhead is connected back to a self-elevating drilling platform by adopting a surface conduit; the top of the high-pressure wellhead adopts a hub end surface, and is connected back to the self-elevating drilling platform by using a drilling riser and a mechanical connector; the internal casing hanger is sent in and recovered by a special tool, so that the whole set of drilling operation is completed; the high-pressure wellhead adopts a high-pressure wellhead form of the end face of the hub, the traditional operation mode of layer-by-layer tieback of the sleeve is changed, all drilling operations can be completed only by matching the high-pressure wellhead with the drilling riser, and the efficiency is obviously improved.
Drawings
FIG. 1 is a side cross-sectional view of a subsea wellhead assembly provided in embodiment 1 of the present invention;
FIG. 2 is a longitudinal cross-sectional view of a low pressure wellhead provided in embodiment 1 of the present invention;
FIG. 3 is a perspective view of a high pressure wellhead provided in embodiment 1 of the present invention;
FIG. 4 is a longitudinal cross-sectional view of a high pressure wellhead provided in embodiment 1 of the present invention;
FIG. 5 is a perspective view of a casing hanger provided in accordance with embodiment 1 of the present invention;
FIG. 6 is a longitudinal cross-sectional view of a casing hanger provided in accordance with embodiment 1 of the present invention;
FIG. 7 is a perspective view of an annular seal assembly provided in accordance with embodiment 1 of the present invention;
fig. 8 is a longitudinal cross-sectional view of an annular seal assembly provided in embodiment 1 of the present invention.
Reference numerals illustrate: 1-a low-pressure wellhead, 10-a sleeve joint groove and 11-a step surface in the low-pressure wellhead; 2-high-pressure wellhead, 20-tooth grooves, 21-high-pressure wellhead outer setting steps, 22-centralizing rings, 23-high-pressure wellhead locking rings and 24-high-pressure wellhead inner step surfaces; 3-annulus sealing assembly, 31-inner metal sealing ring, 32-setting ring, 33-sawtooth locking ring, 34-outer metal sealing ring; 4-casing hanger, 41-lower setting step of casing hanger, 42-circulation channel, 43-sealing surface, 44-internal thread; 100-guiding column, 200-tieback nipple.
Detailed Description
The following examples are illustrative of the invention and are not intended to limit the scope of the invention.
The invention discloses an underwater wellhead assembly for shallow water, wherein a low-pressure wellhead 1 is positioned at the outermost layer, a high-pressure wellhead 2 is arranged in the low-pressure wellhead 1 in a connection mode of setting, righting, locking and the like, a casing hanger 4 is set in the high-pressure wellhead 2, an annular sealing assembly 3 is put down and inserted into an annular gap between the casing hanger 4 and the high-pressure wellhead 2, so that the gap between the annular sealing assembly 3 and the casing hanger 4 and the gap between the annular sealing assembly 3 and the high-pressure wellhead 2 are sealed, and the locking of the annular sealing assembly 3 between the casing hanger 4 and the high-pressure wellhead 2 is realized. According to the underwater wellhead assembly for shallow water, disclosed by the invention, the low-pressure wellhead 1, the high-pressure wellhead 2, the sleeve hanger 4 and the annular sealing assembly 3 are combined to form the underwater wellhead assembly for shallow water, so that quick drilling is realized, the operation efficiency and operability are improved, the use of a mud line hanger is avoided, the level of sleeve tie-back is reduced, the operation risk of subsequent oil pipe four-way and christmas tree installation is reduced, and the operation efficiency is improved.
Example 1: underwater wellhead assembly for shallow water
Referring to fig. 1, the subsea wellhead assembly for shallow water includes a low pressure wellhead 1, a high pressure wellhead 2, an annulus seal assembly 3 and a casing hanger 4.
The low-pressure wellhead 1 is positioned at the outermost layer, the high-pressure wellhead 2 is arranged in the low-pressure wellhead 1, and the casing hanger 4 is arranged in the high-pressure wellhead 2; the annular sealing assembly 3 is arranged between the casing hanger 4 and the high-pressure wellhead 2 in a sealing way and realizes locking of the annular sealing assembly 3 between the casing hanger 4 and the high-pressure wellhead 2.
Preferably, the longitudinal centerlines of the low pressure wellhead 1, the high pressure wellhead 2, the annulus seal assembly 3, and the casing hanger 4 are coincident.
Specifically, the high-pressure wellhead 2 is arranged in the low-pressure wellhead 1, and the connection relationship between the high-pressure wellhead 2 and the low-pressure wellhead 1 comprises setting, righting and locking, and the following is a specific description of the high-pressure wellhead 1:
first, a low-pressure wellhead inner step surface 11 is arranged on the inner wall of the low-pressure wellhead 1, as shown in fig. 2, a high-pressure wellhead outer setting step 21 is arranged on the outer wall of the high-pressure wellhead 2, when the high-pressure wellhead 2 is arranged inside the low-pressure wellhead 1, the high-pressure wellhead outer setting step 21 of the high-pressure wellhead 2 is just clamped on the low-pressure wellhead inner step surface 11 of the low-pressure wellhead 1, and setting of the high-pressure wellhead 2 in the low-pressure wellhead 1 is completed.
In order to be favorable for the high-pressure wellhead 2 to sit and put in the low-pressure wellhead 1, the high-pressure wellhead outer of the high-pressure wellhead 2 sits and puts the step 21 lower part and is provided with the chamfer.
Next, a centering ring 22 is provided between the outer wall of the high pressure wellhead 2 and the inner wall of the low pressure wellhead 1, and the centering ring 22 is located below the high pressure wellhead outer landing step 21, as shown in fig. 1, 3 and 4.
While the high-pressure wellhead 2 is seated in the low-pressure wellhead 1, the centralizing ring 22 can centralize the high-pressure wellhead 2, and maintain an upright state of the concentric structure of the high-pressure wellhead 2 and the low-pressure wellhead 1.
Finally, referring to fig. 3 and 4, a high-pressure wellhead locking ring 23 is arranged on the outer wall of the high-pressure wellhead 2 between the high-pressure wellhead outer setting step 21 and the centralizing ring 22, the high-pressure wellhead locking ring 23 is a C-shaped locking ring, and a sleeve joint groove 10 for sleeve joint the high-pressure wellhead locking ring 23 is arranged on the inner wall of the low-pressure wellhead 1.
When the high-pressure wellhead 2 is pressed down in the low-pressure wellhead 1, the high-pressure wellhead locking ring 23 is just nested in the sleeve joint groove 10 on the inner wall of the low-pressure wellhead 1 while the high-pressure wellhead outer setting step 21 is clamped on the low-pressure wellhead inner step surface 11, so that the high-pressure wellhead 2 is locked in the low-pressure wellhead 1.
With continued reference to fig. 1 and 2, the top of the low pressure wellhead 1 is butted with a plurality of tieback pups 200, and the top of the low pressure wellhead 1 is butted with the tieback pups 200 at the lowest position by anticlockwise screwing, and the tieback pups 200 above the tieback pups 200 at the lowest position are butted by clockwise screwing, and the lower part of the low pressure wellhead 1 is connected with a plurality of surface layer conduits, wherein the surface layer conduits are 30 inches. After the high-pressure wellhead 2 is locked in the low-pressure wellhead 1, the top of the surface layer conduit closest to the low-pressure wellhead 1 is welded with the bottom of the low-pressure wellhead 1; the top of the high-pressure wellhead 2 is provided with a hub end surface for connecting a cable with the christmas tree and the high-pressure drilling riser.
The casing hanger 4 is disposed inside the high-pressure wellhead 2, and adopts a setting form, and the connection relationship between the casing hanger and the high-pressure wellhead is described in detail below.
Specifically, referring to fig. 4 and 5, the inner wall of the high-pressure wellhead 2 is provided with a high-pressure wellhead inner step surface 24, the outer wall of the casing hanger 4 is provided with a casing hanger lower setting step 41, and the casing hanger lower setting step 41 is matched with the high-pressure wellhead inner step surface 24.
In the process of placing the casing hanger 4 into the high-pressure wellhead 2, a setting step 41 at the lower part of the casing hanger 4 is clamped on a step surface 24 in the high-pressure wellhead 2, so that setting of the casing hanger 4 in the high-pressure wellhead 2 is completed.
The casing hanger 4 is internally provided with a circulation channel 42, and when the casing hanger 4 is put in place, mud and cement slurry in well cementation are returned out through the circulation channel 42 of the casing hanger 4 during well cementation work.
In order to facilitate smooth lowering of the casing hanger 4 onto the high pressure wellhead inner step surface 24 of the high pressure wellhead 2, the high pressure wellhead inner step surface 24 of the casing hanger 4 is provided with a chamfer.
The lower inner wall of the casing hanger 4 is provided with an internal thread 44 for threaded connection with the production casing.
The connection of the annular seal assembly 3 to the casing hanger 4 and the high pressure wellhead 2 is described below.
The outer wall of the casing hanger 4 is provided with a sealing surface 43, the inner wall of the lower part of the annular sealing assembly 3 is sleeved on the sealing surface 43 of the casing hanger 4, and the high-pressure wellhead 2 is sleeved on the outer wall of the lower part of the annular sealing assembly 3.
Referring to fig. 5 to 6, the inner wall of the lower part of the annular sealing assembly 3 is provided with a first sealing groove, an inner metal sealing ring 31 is arranged on the first sealing groove, and the annular sealing assembly 3 and the casing hanger 4 are sealed by the inner metal sealing ring 31.
Referring to fig. 7 to 8, a second sealing groove is formed in the outer wall of the lower portion of the annular sealing assembly 3, an outer metal sealing ring 34 is arranged on the second sealing groove, and the annular sealing assembly 3 and the high-pressure wellhead 2 are sealed through the outer metal sealing ring 34.
To facilitate sealing of the annular seal assembly 3 to the casing hanger 4, the sealing surface 43 of the casing hanger 4 is provided as a surface of metallic material.
With continued reference to fig. 7 and 8, the top of the annular sealing assembly 3 is provided with a setting ring 32, the bottom end of the outer wall of the setting ring 32 is provided with a concave, the concave is fixed with a saw tooth locking ring 33 by bolts, and the inner wall of the high-pressure wellhead 2 is provided with saw tooth grooves 20 for sleeving on the saw tooth locking ring 33.
When the lower annular ring hollow sealing assembly 3 is inserted into the annular gap between the casing hanger 4 and the high-pressure wellhead 2, the inner metal sealing ring 31 and the outer metal sealing ring 34 respectively seal the gap between the annular ring sealing assembly 3 and the casing hanger 4 and the gap between the annular ring sealing assembly 3 and the high-pressure wellhead 2, and meanwhile, the setting ring 32 pushes the sawtooth locking ring 33 downwards to enable the sawtooth locking ring 33 to be nested in the sawtooth groove 20 on the inner wall of the high-pressure wellhead 2, so that the annular ring sealing assembly 3 is locked between the casing hanger 4 and the high-pressure wellhead 2.
To facilitate the setting ring 32 to drive the serrated locking ring 33 to complete locking of the annular seal assembly 3, the serrated locking ring 33 top of the annular seal assembly 3 is provided with a chamfer.
In order to facilitate the subsequent installation of the underwater equipment, the underwater wellhead assembly for shallow water further comprises a connecting plate fixedly connected with the outer wall of the low-pressure wellhead 1, and two or four guide posts 100 are arranged on the connecting plate.
Example 2: method for installing underwater wellhead assembly in shallow water sea area
step S1: the lower part of the low-pressure wellhead 1 is connected with a plurality of surface layer conduits; the top of the low-pressure wellhead 1 is butted with a plurality of tie-back pup joints 200, wherein the top of the low-pressure wellhead 1 is butted with the tie-back pup joint 200 at the lowest part by anticlockwise screwing, and the plurality of tie-back pup joints 200 above the tie-back pup joint 200 at the lowest part are butted by clockwise screwing; the low-pressure wellhead 1 and the surface conduit are controlled to be lowered into the wellhead together by the tieback nipple 200 until the low-pressure wellhead is mounted at a preset position.
Step S2: the high-pressure wellhead 2 is lowered to the position that the high-pressure wellhead 2 is arranged inside the low-pressure wellhead 1, the high-pressure wellhead outer setting step 21 is just clamped on the low-pressure wellhead inner step surface 11, and meanwhile, the outer wall of the high-pressure wellhead 2 and the inner wall of the low-pressure wellhead 1 are righted through the righting ring 22; at the same time, the high-pressure wellhead locking ring 23 is just nested in the sleeve joint groove 10 of the inner wall of the low-pressure wellhead 1, so that the high-pressure wellhead 2 is locked in the low-pressure wellhead 1.
Step S3: the tieback nipple 200 is rotated clockwise on the offshore drilling platform, wherein the two adjacent tieback nipples 200 are screwed and butted clockwise, no separation occurs, but the lowest tieback nipple 200 and the low-pressure wellhead 1 are separated, and the recovery of a plurality of tieback nipples 200 is completed.
Step S4: the casing hanger 4 is lowered until the lower setting step 41 of the casing hanger is set on the inner step surface 24 of the high pressure wellhead, and setting of the casing hanger 4 in the high pressure wellhead 2 is completed.
Step S5: after the casing hanger 4 is lowered into place, the well cementation work is carried out, and the mud and cement slurry in the well cementation are returned out through the circulation channel 42 of the casing hanger 4, so that the well cementation is completed.
Step S6: the annular sealing assembly 3 is placed down so as to be inserted into an annular gap between the casing hanger 4 and the high-pressure wellhead 2, the gap between the annular sealing assembly 3 and the casing hanger 4 and the gap between the annular sealing assembly 3 and the high-pressure wellhead 2 are respectively sealed by the inner metal sealing ring 31 and the outer metal sealing ring 34, meanwhile, the setting ring 32 pushes the sawtooth locking ring 33 downwards to be nested in the sawtooth groove 20 on the inner wall of the high-pressure wellhead 2, and locking of the annular sealing assembly 3 between the casing hanger 4 and the high-pressure wellhead 2 is completed, so that installation of the underwater wellhead assembly in a shallow water sea area is completed.
While the invention has been described in detail in the foregoing general description and specific examples, it will be apparent to those skilled in the art that modifications and improvements can be made thereto. Accordingly, such modifications or improvements may be made without departing from the spirit of the invention and are intended to be within the scope of the invention as claimed.
Claims (5)
1. A subsea wellhead assembly for shallow water, comprising:
a low pressure wellhead (1);
a high-pressure wellhead (2) arranged in the low-pressure wellhead (1);
a casing hanger (4) which is arranged in the high-pressure wellhead (2);
the annular sealing assembly (3) is arranged between the casing hanger (4) and the high-pressure wellhead (2) in a sealing manner, and locking of the annular sealing assembly (3) between the casing hanger (4) and the high-pressure wellhead (2) is realized;
the connecting plate is fixedly connected with the outer wall of the low-pressure wellhead (1), two or four guide posts (100) are arranged on the connecting plate,
the top of the low-pressure wellhead (1) is in butt joint with a plurality of tie-back pups (200), the top of the low-pressure wellhead (1) is in butt joint with the tie-back pups (200) at the lowest part through anticlockwise screwing, the tie-back pups (200) above the tie-back pups (200) at the lowest part are in butt joint through clockwise screwing, and the lower part of the low-pressure wellhead (1) is connected with a plurality of surface layer conduits;
the low-pressure wellhead is characterized in that a low-pressure wellhead inner step surface (11) is arranged on the inner wall of the low-pressure wellhead (1), a high-pressure wellhead outer setting step (21) is arranged on the outer wall of the high-pressure wellhead (2), and when the high-pressure wellhead (2) is arranged inside the low-pressure wellhead (1), the high-pressure wellhead outer setting step (21) is just clamped on the low-pressure wellhead inner step surface (11) to finish setting of the high-pressure wellhead (2) in the low-pressure wellhead (1);
a centralizing ring (22) is arranged between the outer wall of the high-pressure wellhead (2) and the inner wall of the low-pressure wellhead (1), and the centralizing ring (22) is positioned below the high-pressure wellhead outer setting step (21);
the centralizing ring (22) can centralize the high-pressure wellhead (2) while the high-pressure wellhead (2) is seated in the low-pressure wellhead (1), and an upright state of a concentric structure of the high-pressure wellhead (2) and the low-pressure wellhead (1) is maintained;
a high-pressure wellhead locking ring (23) is arranged on the outer wall of the high-pressure wellhead (2) between the high-pressure wellhead outer setting step (21) and the centralizing ring (22), and a sleeving groove (10) is arranged on the inner wall of the low-pressure wellhead (1);
when the high-pressure wellhead (2) is in the process of pressing down in the low-pressure wellhead (1), the high-pressure wellhead locking ring (23) is just nested in the sleeve joint groove (10) of the inner wall of the low-pressure wellhead (1) when the high-pressure wellhead outer setting step (21) is clamped on the low-pressure wellhead inner step surface (11), so that the high-pressure wellhead (2) is locked in the low-pressure wellhead (1).
2. A subsea wellhead assembly for shallow water according to claim 1, wherein,
the inner wall of the high-pressure wellhead (2) is provided with a high-pressure wellhead inner step surface (24), the outer wall of the casing hanger (4) is provided with a casing hanger lower part setting step (41), and the casing hanger lower part setting step (41) is matched with the high-pressure wellhead inner step surface (24);
in the process that the casing hanger (4) is lowered into the high-pressure wellhead (2), the lower part setting step (41) of the casing hanger is clamped on the inner step surface (24) of the high-pressure wellhead, and setting of the casing hanger (4) in the high-pressure wellhead (2) is completed.
3. A subsea wellhead assembly for shallow water according to claim 1, wherein,
the casing hanger is characterized in that a sealing surface (43) is arranged on the outer wall of the casing hanger (4), the inner wall of the lower part of the annular space sealing assembly (3) is sleeved on the sealing surface (43) of the casing hanger (4), and the high-pressure wellhead (2) is sleeved on the outer wall of the lower part of the annular space sealing assembly (3).
4. A subsea wellhead assembly for shallow water according to claim 3, wherein,
the inner wall of the lower part of the annular space sealing assembly (3) is provided with a first sealing groove, an inner metal sealing ring (31) is arranged on the first sealing groove, and the annular space sealing assembly (3) and the casing hanger (4) are sealed through the inner metal sealing ring (31);
the outer wall of annulus sealing assembly (3) lower part is provided with the second seal groove, is provided with outer metal sealing ring (34) on the second seal groove, seal through outer metal sealing ring (34) between annulus sealing assembly (3) and high-pressure wellhead (2).
5. A subsea wellhead assembly for shallow water according to claim 4, wherein,
the top of the annular space sealing assembly (3) is provided with a setting ring (32), and the bottom end of the outer wall of the setting ring (32) is provided with a sawtooth locking ring (33);
a saw tooth slot (20) is formed in the inner wall of the high-pressure wellhead (2);
when the annular sealing assembly (3) is pressed down, the annular sealing assembly is inserted into an annular gap between the casing hanger (4) and the high-pressure wellhead (2), the inner metal sealing ring (31) and the outer metal sealing ring (34) respectively seal the gap between the annular sealing assembly (3) and the casing hanger (4) and the gap between the annular sealing assembly (3) and the high-pressure wellhead (2), and meanwhile, the setting ring (32) pushes the sawtooth locking ring (33) downwards to enable the sawtooth locking ring to be nested in a sawtooth groove (20) on the inner wall of the high-pressure wellhead (2), so that locking of the annular sealing assembly (3) between the casing hanger (4) and the high-pressure wellhead (2) is realized.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210607236.6A CN114876398B (en) | 2022-05-31 | 2022-05-31 | Underwater wellhead assembly for shallow water |
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| CN202210607236.6A CN114876398B (en) | 2022-05-31 | 2022-05-31 | Underwater wellhead assembly for shallow water |
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| CN114876398A CN114876398A (en) | 2022-08-09 |
| CN114876398B true CN114876398B (en) | 2023-05-26 |
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Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2391241B (en) * | 2001-04-17 | 2005-05-18 | Fmc Technologies | Nested stack-down casing hanger system for subsea wellheads for annulus pressure monitoring |
| US7240735B2 (en) * | 2003-12-10 | 2007-07-10 | Vetco Gray Inc. | Subsea wellhead assembly |
| CN202544795U (en) * | 2012-02-24 | 2012-11-21 | 宝鸡石油机械有限责任公司 | Underground well opening back connecting device |
| CN203374237U (en) * | 2013-05-17 | 2014-01-01 | 宝鸡石油机械有限责任公司 | External lock type sea underwater wellhead tie-back device |
| CN106320983B (en) * | 2016-11-08 | 2018-12-18 | 贵州高峰石油机械股份有限公司 | A kind of ultra-deep-water is with boring cased method and device |
| CN110552651A (en) * | 2018-06-04 | 2019-12-10 | 上海霞为石油设备技术服务有限公司 | novel deep water well head equipment |
| CN113323606A (en) * | 2021-07-01 | 2021-08-31 | 中海石油(中国)有限公司 | Connecting device suitable for underwater wellhead and surface guide pipe piling construction and assembling method |
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