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United States Patent Application 20170130547
Kind Code A1
Bhatnagar; Samved ;   et al. May 11, 2017

INSTALLATION ASSEMBLY FOR A SUBSEA WELLHEAD

Abstract

A system for load transfer from a wellhead to the sea bed adjacent a subsea well, including a suction pile for securing to the sea bed, and a wellhead housing assembly having a longitudinal axis and attached to the suction pile, the wellhead housing for subjection to an axial load acting in a direction parallel to the longitudinal axis, and a bending load acting in a direction not parallel to the longitudinal axis. The system further includes a suction pile connector that transmits the axial load and the bending load from the wellhead housing through the suction pile toward the sea bed, and that is attached to the suction pile, the suction pile connector engaged with the wellhead housing to substantially maintain the relative positions of the wellhead housing and the suction pile.


Inventors: Bhatnagar; Samved; (Houston, TX) ; Clark; Jonathan; (Houston, TX) ; Voss; Robert K.; (Houston, TX)
Applicant:
Name City State Country Type

Vetco Gray, Inc.

Houston

TX

US
Assignee: Vetco Gray, Inc.
Houston
TX

Family ID: 1000002439253
Appl. No.: 15/344204
Filed: November 4, 2016


Related U.S. Patent Documents

Application NumberFiling DatePatent Number
62251803Nov 6, 2015

Current U.S. Class: 1/1
Current CPC Class: E21B 33/038 20130101; E21B 7/12 20130101; E02D 5/22 20130101
International Class: E21B 33/038 20060101 E21B033/038; E02D 5/22 20060101 E02D005/22

Claims



1. A system for load transfer from a wellhead to the sea bed adjacent a subsea well, comprising: a suction pile for securing to the sea bed; a wellhead housing having a longitudinal axis and attached to the suction pile, the wellhead housing for subjection to an axial load acting in a direction parallel to the longitudinal axis; and a suction pile connector that transmits the axial load from the wellhead housing through the suction pile toward the sea bed, and that is attached to the suction pile, the suction pile connector engaged with the wellhead housing to substantially maintain the relative positions of the wellhead housing and the suction pile.

2. The system of claim 1, wherein the suction pile connector substantially circumscribes the wellhead housing and has an inner surface defining a recess, and wherein the suction pile connector further comprises a dog connector positioned in the recess and movable toward the longitudinal axis of the wellhead housing into engagement with the wellhead housing to restrict relative axial movement between the suction pile connector and the wellhead housing.

3. The system of claim 2, wherein the dog connector has teeth extending toward the wellhead housing to engage the wellhead housing.

4. The system of claim 3, wherein the wellhead housing has an outer surface with ridges positioned to correspond to the teeth so that when the dog connector moves into engagement with the wellhead housing, the teeth of the dog connector engage the ridges of the wellhead housing.

5. The system of claim 4, wherein the teeth of the dog connector each have a lower surface, and the ridges of the wellhead housing each have an upper surface, and when the axial load is applied to the system, the lower surfaces of the teeth engage with the upper surfaces of the ridges so that the axial load is transmitted from the wellhead housing to the suction pile connector through the dog connector.

6. The system of claim 2, wherein the dog connector is hydraulically actuated.

7. The system of claim 2, wherein the dog connector is mechanically actuated.

8. A system for load transfer from a wellhead to the sea bed adjacent a subsea well, comprising: a suction pile for securing to the sea bed; a wellhead housing having a longitudinal axis and attached to the suction pile, the wellhead housing for subjection to a bending load acting in a direction not parallel to the longitudinal axis; and a suction pile connector that transmits the bending load from the wellhead housing through the suction pile toward the sea bed, and that is attached to the suction pile, the suction pile connector engaged with the wellhead housing to substantially maintain the relative positions of the wellhead housing and the suction pile.

9. The system of claim 8, wherein the wellhead housing has an outer surface with an outwardly directed shoulder.

10. The system of claim 9, wherein the suction pile connector has an inner surface with an inwardly directed shoulder positioned to correspond to the outwardly directed shoulder of the outer surface of the wellhead housing.

11. The system of claim 10, wherein when the bending load is applied to the wellhead housing, rotational movement of the wellhead housing relative to the suction pile connector is restricted by engagement of the outwardly directed shoulder of the outer surface of the wellhead housing with the inwardly directed shoulder of the suction pile connector.

12. The system of claim 10, wherein the wellhead housing is subjected to an axial load acting in a direction parallel to the longitudinal axis, and the suction pile connector transmits the axial load from the wellhead housing through the suction pile toward the sea bed.

13. The system of claim 12, wherein the suction pile connector substantially circumscribes the wellhead housing and has an inner surface defining a recess, and wherein the suction pile connector further comprises a dog connector positioned in the recess and movable toward the longitudinal axis of the wellhead housing into engagement with the wellhead housing to restrict relative axial movement between the suction pile connector and the wellhead housing.

14. The system of claim 13, wherein the dog connector has teeth extending toward the wellhead housing to engage the wellhead housing, and the wellhead housing has an outer surface with ridges positioned to correspond to the teeth.

15. The system of claim 14, wherein when the bending load is applied to the wellhead housing, rotational movement of the wellhead housing relative to the suction pile connector is restricted by engagement of the outwardly directed shoulder of the outer surface of the wellhead housing with the inwardly directed shoulder of the suction pile connector, and the teeth of the dog connector do not contact the ridges of the wellhead connector.

16. A method of transmitting a load from well equipment to a sea floor, the method comprising: a) coupling the well equipment to a suction pile using a suction pile connector, the suction pile connector defining a recess with a dog connector, the dog connector having at least one tooth for engagement with the well equipment; b) transmitting an axial load from the well equipment to the dog connector via the tooth of the dog connector; c) transmitting the axial load from the dog connector to the suction pile connector; d) transmitting the axial load from the suction pile connector to the suction pile; and e) transmitting the axial load from the suction pile to the sea floor.

17. The method of claim 16, wherein the well equipment has a shoulder and the suction pile connector has a corresponding shoulder, the method further comprising: transmitting a bending load from the well equipment to the suction pile connector via the well equipment shoulder and the suction pile connector shoulder.

18. The method of claim 17, further comprising: transmitting the bending load from the suction pile connector to the suction pile; and transmitting the bending load from the suction pile to the sea floor.

19. The method of claim 16, further comprising: f) prior to step b), driving the at least one tooth of the dog connector into engagement with the well equipment using hydraulic or mechanical force.

20. The method of claim 19, wherein the well equipment at least one ridge on an outer surface thereof, and step f) further comprises: driving the at least one tooth of the dog connector into engagement with the at least one ridge of the outer surface of the well equipment.
Description



CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of, co-pending U.S. Provisional Application Ser. No. 62/251,803, filed Nov. 6, 2015, the full disclosure of which is hereby incorporated herein by reference in its entirety for all purposes.

BACKGROUND

[0002] Field of Invention

[0003] This invention relates in general to equipment used in the hydrocarbon industry, and in particular, to systems and methods for subsea drilling operations.

[0004] Description of the Prior Art

[0005] Typical subsea drilling operations include a drilling vessel and an arrangement of equipment to accomplish the first drilling phase of a well. In many known systems, for example, the first phase of the drilling operation may include jetting. Jetting is a process wherein a jetting tool, enclosed within a casing, is placed adjacent the sea floor. Fluid is sprayed through the end of the jetting tool and directed at the sand on the sea floor. The fluid is turbulent and stirs up the sand, which mixes with the fluid and is carried up the casing away from the bottom of the casing. When the sand is thus removed, the casing is lowered into the void left behind. This process is continued until the casing reaches a predetermined depth, after which equipment related to the next phase of drilling (i.e. a high pressure housing, blow out preventer, marine riser, etc.) is connected.

[0006] Jetting and other operation typically require heavy equipment, which is handled by a drilling rig, often mounted to a vessel or platform at the sea surface. Certain exploratory or other types of drilling operations, however, can lower operational costs by enabling a flexible approach to well construction that can be carried out by a smaller vessel needing less infrastructure and space to support heavy equipment. Using this method, the wellhead can be installed using a suction pile. Such a method typically requires installation of the wellhead on the suction pile, or a frame that consists of multiple suction piles, at the surface, and then lowering the suction pile to the sea floor.

[0007] One problem that can occur in known system relates to the reduction in weld life of the joints in the low and high pressure housing of the wellhead. The welds connecting the respective casings to the low and high pressure housing can be subjected to frequent cyclic loading caused by equipment connected to the wellhead, such as the BOP, riser, tensioners, etc., and the side loading subjected by wave currents, drift of the ship in the sea, etc. Over time, such axial and bending forces degrade the welded connections between the low and high pressure housing of the wellhead and the respective casings, leading to failure and a potential risk for hydrocarbons to leak to the surface during drilling or production. In addition, the weld locations are also not very accessible post-installation of the wellhead to the seabed and hence, difficult to repair.

SUMMARY

[0008] One embodiment of the present technology provides a system for load transfer from a wellhead to the sea bed adjacent a subsea well, including a suction pile for securing to the sea bed, and a wellhead housing having a longitudinal axis and attached to the suction pile, the wellhead housing for subjection to an axial load acting in a direction parallel to the longitudinal axis. The system further includes a suction pile connector that transmits the axial load from the wellhead housing through the suction pile toward the sea bed, and that is attached to the suction pile, the suction pile connector engaged with the wellhead housing to substantially maintain the relative positions of the wellhead housing and the suction pile.

[0009] Another embodiment of the present technology provides a system for load transfer from a wellhead to the sea bed adjacent a subsea well, including a suction pile for securing to the sea bed, and a wellhead housing having a longitudinal axis and attached to the suction pile, the wellhead housing for subjection to a bending load acting in a direction not parallel to the longitudinal axis. The system further includes a suction pile connector that transmits the bending load from the wellhead housing through the suction pile toward the sea bed, and that is attached to the suction pile, the suction pile connector engaged with the wellhead housing to substantially maintain the relative positions of the wellhead housing and the suction pile.

[0010] Yet another embodiment of the present technology provides a method of transmitting a load from well equipment to a sea floor. The method includes coupling the well equipment to a suction pile using a suction pile connector, the suction pile connector defining a recess with a dog connector, the dog connector having at least one tooth for engagement with the well equipment, and transmitting an axial load from the well equipment to the dog connector via the tooth of the dog connector. The method further includes transmitting the axial load from the dog connector to the suction pile connector, transmitting the axial load from the suction pile connector to the suction pile, and transmitting the axial load from the suction pile to the sea floor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present technology will be better understood on reading the following detailed description of non-limiting embodiments thereof, and on examining the accompanying drawings, in which:

[0012] FIG. 1 is a side schematic view of a drilling operation according to an embodiment of the present technology;

[0013] FIG. 2 is an isometric view of a suction pile connector and associated elements according to an embodiment of the present technology;

[0014] FIG. 3 is an enlarged side cross-sectional view of the section pile connector of FIG. 2 taken along line 3-3 of FIG. 2;

[0015] FIG. 4 is an enlarged side cross-sectional view of an interface between a wellhead housing and a suction pile connector according to another embodiment of the present technology;

[0016] FIG. 5 is an alternate view of the enlarged side cross-sectional view of the interface between the wellhead housing and the suction pile connector of FIG. 4;

[0017] FIG. 6 is an alternate view of the enlarged side cross-sectional view of the interface between the wellhead housing and the suction pile connector of FIG. 4 when under an axial load;

[0018] FIG. 7 is an alternate view of the enlarged side cross-sectional view of the interface between the wellhead housing and the suction pile connector of FIG. 4 when under a bending load; and

[0019] FIG. 8 is an alternate view of the enlarged side cross-sectional view of the interface between the wellhead housing and the suction pile connector of FIG. 4 when under both an axial and a bending load.

DETAILED DESCRIPTION OF THE INVENTION

[0020] The foregoing aspects, features and advantages of the present technology will be further appreciated when considered with reference to the following description of preferred embodiments and accompanying drawings, wherein like reference numerals represent like elements. In describing the preferred embodiments of the technology illustrated in the appended drawings, specific terminology will be used for the sake of clarity. The invention, however, is not intended to be limited to the specific terms used, and it is to be understood that each specific term includes equivalents that operate in a similar manner to accomplish a similar purpose.

[0021] Embodiments of this disclosure provide systems and methods of installing a wellhead assembly using a suction pile and enabling a more robust transfer of installation and operational loads to the sea bed during the entire life cycle of the well. During exploration, utilization of such a wellhead assembly configuration enables operators to use a lower day-rate vessel for construction of the well before the drilling activity and allows, for example, for lower cost drilling.

[0022] FIG. 1 shows a side schematic view of a subsea drilling operation, according to one example embodiment of the present technology. The drilling operation includes a vessel 10 floating on the sea surface 12 substantially above a wellbore 14. A wellhead housing 16 sits at the top of the wellbore 14 and is connected to a blowout preventer (BOP) assembly 18, which may include shear rams 20, sealing rams 22, and/or an annular ram 24. One purpose of the BOP assembly 18 is to help control pressure in the wellbore 14. The BOP assembly 18 is connected to the vessel 10 by a riser 26. During drilling operations, a drill string 28 passes from a derrick 30 on the vessel 10, through the riser 26, through the BOP assembly 18, through the wellhead housing 16, and into the wellbore 14. The lower end of the drill string 28 is attached to a drill bit 32 that extends the wellbore 14 as the drill string 28 turns. Additional features shown in FIG. 1 include a mud pump 34 with mud lines 36 connecting the mud pump 34 to the BOP assembly 18, and a mud return line 38 connecting the mud pump 34 to the vessel 10. A remotely operated vehicle (ROV) 40 can be used to make adjustments to, repair, or replace equipment is necessary. Although a BOP assembly 18 is shown in the figures, the wellhead housing 16 could be attached to other well equipment as well, including, for example, a tree, a spool, a manifold, or another valve or completion assembly.

[0023] One efficient way to start drilling a wellbore 14 is through use of a suction pile 42. Such a procedure is accomplished by attaching the wellhead housing 16 to the top of the suction pile 42 and lowering the suction pile 42 to the sea floor 44. As interior chambers in the suction pile 42 are evacuated, the suction pile 42 is driven into the sea floor 44, as shown in FIG. 1, until the suction pile 42 is substantially submerged in the sea floor 44 and the wellhead housing 16 is positioned at the sea floor 44 so that further drilling can commence. As the wellbore 14 is drilled, the walls of the wellbore are reinforced with concrete casings 46 that provide stability to the wellbore 14 and help to control pressure from the formation.

[0024] More specifically, the wellhead assembly, including the wellhead housing 16, is mounted on top of the suction pile 42 and held axially while lowering to the sea floor 44. Depending on the soil conditions, in certain cases, only a low pressure housing may be mounted on top of the suction pile while the high pressure housing is installed in a secondary drilling and cementing operation. Once the suction pile 42 and wellhead assembly reaches the seabed, an ROV can shut off the water access hatch and actuate a valve to pump fluid from within the suction pile 42, and enable the suction pile 42 to be installed in the seabed. The wellhead assembly can be installed on a single suction pile 42 or on a frame that consists of multiple suction piles 42. The suction pile(s) 42 can have a greater outer diameter than the cemented casing 46 that extends into the well. As an example the cemented casing 46 can have a maximum outer diameter of 36 inches while a suction pile 42 can have an outer diameter of up to 20 feet, or can include one or more piles with an outer diameter of 20 feet or more.

[0025] Referring now to FIG. 2, there is shown the suction pile 42, BOP assembly 18, and wellhead housing 16. The wellhead housing 16 includes a high pressure housing 48 and a low pressure housing 50. Also shown in FIG. 2 is a suction pile connector 52, which serves to connect the wellhead housing 16 to the suction pile 42. Although a single suction pile 42 is shown, multiple suction piles can be used, with a frame connecting the multiple suction piles. The suction pile connector 52 of the present technology is advantageous because it provides a secure way to connect the wellhead housing 16 to the suction pile 42 that is capable of withstanding forces on the wellhead housing 16, including axial forces, which act on the connection in the axial direction indicated by arrows F.sub.A, and bending forces, which act on the connection as indicated by arrow F.sub.M. Axial forces F.sub.A may be produced, for example, by tension in the riser 26, which exerts an upward force on the BOP assembly, and in turn on the wellhead housing 16, as well as the weight of the casing (not shown) extending from the wellhead housing 16 downward into the wellbore 14. Bending forces F.sub.M may be produced, for example, by ocean currents or other environmental conditions acting on the riser 26, BOP assembly 18, etc., lateral to the axis of the suction pile 42 and the wellhead housing 16.

[0026] In some known systems, the wellhead housing 16 has simply been welded or otherwise fastened to the suction pile 42 using fasteners, such as bolts. Such connections are often inadequate, however, for the rigors of the subsea environment. For example, riser tension and ocean currents can vary over time, thereby causing cyclical loading of the connection between the wellhead housing 16 and the suction pile 42 over time. Such cyclical loading can lead to fatigue in the components, and ultimately to costly repairs or failure. The suction pile connector 52, on the other hand, advantageously couples the wellhead housing 16 to the suction pile 42 in a way that reduces wear caused by axial and bending forces F.sub.A, F.sub.M on the connection between the wellhead housing 16 and the suction pile 42.

[0027] An enlarged cross-sectional view of the suction pile connector 52 is shown in FIG. 3, along with the suction pile 42, the low pressure housing 50, and the high pressure housing 48. As shown, the high pressure housing 48 has a bore 54 extending axially through the high pressure housing 48 parallel to the longitudinal axis A of the assembly. It is through this bore 54 that the drill string 28 (shown in FIG. 1) passes as it extends into the wellbore 14. The high pressure housing 48 is circumscribed by the low pressure housing 50. The high pressure housing 48 and the low pressure housing 50 may be locked together using a lock ring 56. Axial movement between the high pressure housing 48 and the low pressure housing 50 may be further restricted by the geometry of the housings 48, 50. For example, shoulders 58 of the high pressure housing 48 may interfere with shoulders 60 of the low pressure housing 50 to restrict downward axial movement of the high pressure housing 48 relative to the low pressure housing 50.

[0028] The suction pile connector 52 can be attached to the suction pile 42 in any appropriate way. For example, as shown in FIG. 3, the suction pile connector 52 can be attached to the suction pile 42 using fasteners 62. Alternately, the suction pile connector 52 and suction pile 42 can be welded together, or the suction pile connector 52 can be integrally formed with the suction pile 42. The suction pile connector 52 extends upwardly from the suction pile 42 toward the wellhead housing 16, and substantially surrounds a portion of the low pressure housing 50. The geometry of the suction pile connector 52 relative to the low pressure housing 50, as described in greater detail below with regard to FIGS. 9 and 10, can help to resist bending loads. This geometry of the present technology thus enables a side, or bending load on the wellhead housing 16 to be transmitted to the suction pile connector 52, from the suction pile connector 52 to the suction pile 42, and from the suction pile to the sea floor 44. Thus, wellhead welds 63, surface casing, and cement in the annulus is prevented from encountering any side or tension loading, which mitigates or eliminates fatigue life concerns of the conductor or surface casing welds.

[0029] In certain embodiments, such as the embodiment shown in FIG. 3, the suction pile connector 52 can include one or more recesses 64, and the recesses 64 can each accept a dog connector 66 having teeth 68 extending inwardly toward the low pressure housing 50. The teeth 68 of the dog connector 66 can correspond to ridges 70 on the outer surface of the low pressure housing 50. The dog connector 66 can be moved, either hydraulically (e.g. using hydraulic piston actuated dogs) or mechanically (e.g., using screw driven dogs), inwardly toward the low pressure housing 50 until the teeth 68 of the dog connector 66 engage the ridges 70 of the low pressure housing 50, thereby locking the low pressure housing 50 relative to the suction pile connector 52. In such engaged position, the interface between the teeth 68 of the dog connectors 66 and the ridges 70 of the low pressure housing 50 can serve to transmit axial forces between the suction pile 42 and the low pressure housing 50.

[0030] FIGS. 6-10 depict a step by step process of making up the connection between the suction pile connector 52 and the low pressure housing 50, using the dog connections 66, according to one embodiment of the present technology. These figures also show the interaction between the suction pile connector 52, the low pressure housing 50, and the dog connections 66 as forces act on components of the system.

[0031] In FIG. 4 there is shown the suction pile connector 52, with the dog connector 66 fully retracted into the recess 64. In this configuration, there is minimal interference between the teeth 68 of the dog connector 66 and the ridges 70 of the low pressure housing 50 as the connection is made up. These allows easy insertion of the low pressure housing into the suction pile connector 52 when components of the system are assembled, a process which typically occurs at the surface, prior to lowering the suction pile/well housing combination to the sea floor. During the phase of the process shown in FIG. 4, the teeth 68 of the dog connectors 66 and the ridges 70 of the low pressure housing 50 can be disengaged, or can be pre-loaded. Although three teeth 68 are shown in the figures, it is to be understood that more or fewer teeth could be used in alternate embodiments of the technology. Also shown in FIG. 4 are the suction pile connector shoulder 78 and the low pressure housing shoulder 80. The suction pile connector shoulder 78 and low pressure housing shoulder 80 are arranged adjacent to one another when the suction pile connector 52 is fully in place relative to the low pressure housing 50.

[0032] FIG. 5 depicts inward movement of the dog connector 66 toward the low pressure housing 50 as indicated by arrow B. Such movement of the dog connector 66 can be driven by any appropriate means. In some embodiments, the dog connector can be controlled by hydraulics. In others it can be driven mechanically, such as using an ROV, or the connection can be made at the surface. As the dog connector 66 moves toward the low pressure housing 50, the teeth 68 of the dog connector 66 engage the ridges 70 of the low pressure housing 50. As the teeth 68 become engaged with the ridges 70, the suction pile connector shoulder 78 and low pressure housing shoulder 80 remain aligned adjacent one another.

[0033] FIG. 6 shows the relative positions of the suction pile connector 52, low pressure housing 50, and dog connector 66 when an axial force F.sub.A is applied to the connection. Specifically, when such an axial force F.sub.A is applied to the low pressure housing 50, a lower surface 82 of each tooth 68 of the dog connector 66, contacts or engages an upper surface 84 of each ridge 70 of the low pressure housing 50. This contact restricts movement of the low pressure housing 50 relative to the suction pile connector 52, with load being transmitted through the teeth 68 of the dog connector 66 to the suction pile connecter 52, and not through the weld on the casing 63 (shown in FIG. 3), casing, casing hanger or other equipment attached directly or indirectly to the wellhead housing. In addition, it is to be understood that, although not shown in the figures, if the axial force were acting in the opposite direction, the connection would behave in the same way. That is, the top surface 86 of each tooth 68 of the suction pile connector 52 would contact the bottom surface 88 of each ridge 70 of the los pressure housing 50, thereby limiting movement of the suction pile connector 52 relative to the low pressure housing 50 and transmitting the axial force F.sub.A through the teeth 68 of the dog connector 66.

[0034] FIG. 7 shows the relative positions of the suction pile connector 52, low pressure housing 50, and dog connector 66 when a bending force F.sub.M is applied to the connection. The solid line 90 indicates the position of the outer surface of the low pressure housing 50 before application of the bending force F.sub.M. The dotted line 92 shows the position of the outer surface of the low pressure housing 50 after application of the bending force F.sub.M. Specifically, when such a bending force F.sub.M is applied, the low pressure housing shoulder 80 rotates upward until it contacts the suction pile connector shoulder 78, which restricts further movement of the low pressure housing 50 relative to the suction pile connector 52. As the low pressure housing shoulder 80 and suction pile connector shoulder 78 engage, the upper and lower surfaces 82, 86 of the teeth 68 of the dog connector 66 remain substantially out of contact with the upper and lower surfaces 84, 88 of the ridges of the low pressure housing 50. Thus, the bending forces are transmitted substantially through the shoulders 78, 80 of the suction pile connector 52 and low pressure housing 50, and not through the dog connector 66 or its teeth 68.

[0035] FIG. 8 depicts the relative positions of the suction pile connector 52, the low pressure housing 50, and the dog connector 66 when an axial force F.sub.A and a bending force F.sub.M are simultaneously applied. In such a situation, axial force F.sub.A causes the lower surfaces 82 of the teeth 68 of the dog connector 66 to engage the upper surfaces 84 of the ridges 70 of the low pressure housing 50, so that the dog connectors bear the axial load. At the same time, the bending force F.sub.M causes suction pile connector shoulder 78 to contact the low pressure housing shoulder 80, so that the bending load is transferred directly between the suction pile connector 52 and the low pressure housing 50, and not transmitted through the dog connection 66.

[0036] The present technology provides many advantages over known methods and systems of connecting a wellhead assembly to a suction pile. For example, by forming load paths as described above, forces that are directed through the conductors and cement in the wells of known systems can be redirected to travel instead through the wiser diameter of the suction pile directly into the sea bed. This way radial or tensile loading of wellhead welds, surface casing, and cement in the annulus can be reduced and fatigue life of the conductor and surface casing welds is improved. The loads of the suction pile are transmitted from the outer diameter of the suction pile through to the sea bed. This results in a longer fatigue life for the wellhead assembly and a longer cement life for the cement in the annulus between the casings.

[0037] In alternate designs, the suction pile connector can provide a load path for a portion of the tension loads and a minimal to no part of the bending loads or side loads; a portion of the bending or side lads and a minimal to no part of the tension loads; or a portion of both the tension loads and the bending or side loads. The portion of loads can be, for example, more than 50% of the applicable loads applied to the wellhead assembly and in alternate embodiments can be more than 80% of the applicable loads applied to the wellhead assembly. The load sharing is dependent on the design intent and the actual application.

[0038] The suction pile can provide a load path for loads applied to the wellhead assembly during installation of the wellhead assembly, such as when the suction pile is used as an installation tool. The suction pile can alternately provide a load path for loads applied to the wellhead assembly, and act as a wellhead assembly foundation and transfer operational loads during operation of the subsea well. The suction pile can alternately provide a load path for loads applied to the wellhead assembly both during installation of the wellhead assembly and during operation of the subsea well.

[0039] Although the technology herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present technology. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present technology as defined by the appended claims.

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