Drilled pile anchor and method

The method using a MODU to drill and cement anchor piles addresses limitations of existing systems by providing versatile and robust anchoring in various water bottom formations, ensuring strong mooring.

WO2025202681A1PCT designated stage Publication Date: 2025-10-02NOBLE DRILLING AS
View PDF 2 Cites 0 Cited by

Patent Information

Application Number
PCT/IB2024/052909
Authority / Receiving Office
WO · WO
Patent Type
Applications
Current Assignee / Owner
Filing Date
2024-03-26
Publication Date
2025-10-02

AI Technical Summary

Technical Problem

Existing mooring systems, such as those described in International Application Publication No. WO 2023/031576, are limited in utility to certain types of water bottom formations and require improved devices for anchoring vessels and platforms to the water bottom.

Method used

A method involving a mobile offshore drilling unit (MODU) to drill a hole, insert an anchor pile, and cement it in place, with optional reinforcement and tension testing, allowing for versatile anchoring in various formations.

Benefits of technology

Enables robust and versatile anchoring in diverse water bottom conditions, enhancing mooring strength and reliability.

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure IB2024052909_02102025_PF_FP_ABST
    Figure IB2024052909_02102025_PF_FP_ABST
Patent Text Reader

Abstract

A method for setting an anchor pile includes moving a mobile offshore drilling unit (MODU) such that at least one hoist unit in the MODU is disposed over a water bottom location for setting the anchor pile. A hole is drilled through the water bottom for receiving the anchor pile. A drill string and bottom hole assembly (BHA) used to drill the hole are removed. The anchor pile is extended into the hole; Cement is pumped through a cementing string extended from the MODU and through the anchor pile. The cementing string is disconnected from the anchor pile. After the cement is cured, tension is applied from a line or string extended from the MODU to test mooring strength of the anchor pile.
Need to check novelty before this filing date? Find Prior Art

Description

DRILLED PILE ANCHOR AND METHODBackground

[0001] This disclosure relates to the field of mooring systems for floating platforms. More particularly, the disclosure relates to anchor piles disposed in sediments and / or rock formations below the bottom of a body of water.

[0002] Mooring devices known in the art include drag embedment anchors, suction piles and driven piles. International Application Publication No. WO 2023 / 031576 in the name of Reflex Marine Ltd. describes a drilled pipe anchoring system for use in various types of water bottom formations. The disclosed system comprises an anchor pile configured to be embedded in a borehole drilled in the water bottom. The anchor pile comprises an elongate main body having an upper end and a lower end. The cross section of the elongate main body increases along a portion of the longitudinal axis of the main body in the direction from the upper end to the lower end defining at least one bearing surface such that in use an annular gap for receiving locking media is defined between the at least one bearing surface and the adjacent portions of the borehole. The anchor pile is locked in position within the borehole on receipt of locking media, e.g., cement, within the annular gap (32) and abutment of the loose material with the bearing surface.

[0003] The mooring device and method disclosed in the ‘576 publication requires a fit for purpose anchor pile, and may be limited in utility to certain types of water bottom formations.

[0004] There continues to be a need for improved devices for anchoring vessels and platforms to the water bottom.Summary

[0005] One aspect of the present disclosure is a method for setting an anchor pile in formations below the bottom of a body of water. A method according to this aspect includes moving a mobile offshore drilling unit (MODU) such that at least one hoist unit in theMODU is disposed over a water bottom location for setting the anchor pile. A hole is drilled through the water bottom for receiving the anchor pile. A drill string and bottom hole assembly (BHA) used to drill the hole are removed. The anchor pile is extended into the hole; Cement is pumped through the anchor pile. The cementing string is disconnected from the anchor pile. After the cement is cured, tension is applied from a line or string extended from the MODU to test mooring strength of the anchor pile.

[0006] In some embodiments, the MODU comprises first and a second, spaced apart hoist units, and wherein drilling the hole is performed by the BHA extended at the end of a drill string from the first hoist unit, and the anchor pile is extended into the body of water by the second hoist unit.

[0007] In some embodiments, the anchor pile is extended into the hole by removing the BHA from the hole, moving the MODU such that the second hoist unit and the extended anchor pile are disposed over the hole, and extending the anchor pile into the hole.

[0008] In some embodiments, the disconnecting the cementing string comprises rotating the cementing string to unthread a threaded connector disposed between the cementing string and the sacrificial cementing line.

[0009] In some embodiments, the applying tension comprises extending a line or chain from the MODU, connecting the line or chain to a mooring cap disposed on an upper end of the anchor pile, and withdrawing the line or chain using the MODU.

[0010] Some embodiments further comprise reinforcing the anchor pile by installing at least one type of reinforcement to an interior of the anchor pile.

[0011] In some embodiments, the at least one type of reinforcement comprises at least one of, T bars, a pipe nested in the anchor pile wherein an annular space between the nested pipe and the anchor pile is filled with cement, reinforcing rods, or filling an interior of the anchor pile with cement.

[0012] In some embodiments, the anchor pile is provided with slot to allow a chain to pass through.

[0013] In some embodiments, the slot extends longitudinally to an exit point below an upper longitudinal end of the anchor pile.

[0014] In some embodiments, a mooring chain is fixedly connected to the anchor pile proximate the exit point.

[0015] In some embodiments, the mooring chain is extended outside of the anchor pile and pulled sideways before the pumping cement.

[0016] In some embodiments, the anchor pile comprises a sacrificial cementing line extending longitudinally therethrough and nested within the anchor pile.

[0017] An anchor pile for water bottom mooring attachment according to another aspect of the disclosure includes a conduit, and a mooring cap attached to an end of the conduit. The mooring cap has an opening for passage therethrough of a cementing line. The mooring cap has a feature for attachment of a mooring line. The cementing line is nested within and extends past the end of the conduit and past an opposed end of the conduit. The cementing line comprises a running tool at one end having a coupling enabling releasable connection to a pipe string extending from a drilling unit on a surface of a body of water.

[0018] Some embodiments further comprise a reinforcement disposed in an interior of the conduit.

[0019] In some embodiments, the reinforcement comprises at least one of T bars, a pipe nested in the conduit wherein an annular space between the nested pipe and the conduit is filled with cement, reinforcing rods, or filling an interior of the conduit with cement.

[0020] In some embodiments, an annular space between the cementing line and the conduit is closed at a longitudinal end of the conduit opposed to the mooring cap.

[0021] Other aspects and possible advantages will be apparent from the description and claims that follow.Brief Description of the Drawings

[0022] FIGS. 1 through 12 show a sequence of actions in an example embodiment of a method according to the present disclosure. FIG. 1 shows moving a mobile offshore drilling unit (MODU) to an anchor pile location on the water bottom.

[0023] FIG. 2 shows extending a drilling bottom hole assembly (BHA) from one drill center on the MODU toward the water bottom.

[0024] FIG. 2A shows an enlarged view of the BHA.

[0025] FIG. 3 shows the BHA drilling the formations below the water bottom while an anchor pile, e.g., in the form of a conductor pipe, is extended from a second drill center on the MODU.

[0026] FIG. 3A shows an enlarged view of the BHA.

[0027] FIG. 4 shows continuing drilling with the BHA to a selected depth in the subbottom formations while the anchor pile continues to be extended from the MODU.

[0028] FIG. 4A shows drilling the hole in a direction deviated from vertical.

[0029] FIG. 4B shows the bottom of the anchor pile may be flared.

[0030] FIG. 5 shows the MODU retrieving the BHA and extending the anchor pile.

[0031] FIG. 6 shows extending the anchor pile into the hole drilled by the BHA.

[0032] FIG. 6A shows an enlarged view of the top of the anchor pile, including a mooring cap and internal reinforcement.

[0033] FIG. 6B shows an example embodiment of the mooring cap and a sacrificial cementing pipe string

[0034] FIGS. 6C through 6G show example embodiments of internal reinforcement for the anchor pile

[0035] FIG. 6H shows a vertical section view of the top of the anchor pile with reinforcement placed therein.

[0036] FIG. 7 shows running the anchor pile into the hole prior to installation of cement at the end of a cementing string.

[0037] FIG. 7A shows an enlarged view of a lower end of the anchor pile in FIG. 7 indicating protrusion of the sacrificial cementing pipe string from the bottom of the anchor pile.

[0038] FIG. 8 shows the anchor pile fully inserted and being cemented in place in the hole.

[0039] FIG. 9 shows releasing the cementing string from the anchor pile after cement is cured.

[0040] FIG. 9A shows an enlarged view of the upper end of the anchor pile with a cementing string disconnected.

[0041] FIG. 10 shows retrieving the cementing string and waiting for the cement to cure.

[0042] FIG. 11 shows using a work string to extend a mooring connector to engage the mooring cap at the upper end of the anchor pile.

[0043] FIG. 11 A shows an enlarged view of the mooring connector being attached to the mooring cap the upper end of the anchor pile.

[0044] FIG. 12 shows applying tension to the work string to test the pull strength of the assembled mooring connector and anchor pile.

[0045] FIG. 12A shows an enlarged view of a chain used to connect the mooring cap to the work string for the pull strength test.

[0046] FIG. 13 shows an example implementation wherein a template supports multiple anchor piles at a single mooring location on the water bottom.

[0047] FIGS. 14, 14A and 14B show an example implementation comprising a slot in an anchor pile to enable extension of a mooring line or chain from a location below the top of the anchor pile, thereby reducing bending moment.Detailed Description

[0048] FIG. 1 shows a mobile offshore drilling unit (MODU) 10 moving to an anchor pile location 13 A on the bottom 13 of a body of water 15. The MODU 10 is illustrated as a drill ship, however the form of the MODU is not a limitation on the scope of the presentdisclosure. Other forms of MODU may include, for example and without limitation, semisubmersible drilling platforms. In some embodiments, the MODU 10 may be self- propelled and comprise dynamic positioning equipment (not shown) to maintain the position of the MODU 10 as needed without requirements for fixed mooring from the water bottom for subsequent actions to be explained further below.

[0049] The MODU 10 may comprise one or more vertical pipe support structures (derricks) 10A in which lengths of pipe may be stored for conveyance by one or more hoisting units 10A1, 10A2 (explained further below) associated with the derrick 10A. Lengths of such pipes needed to perform operations, to be explained in more detail below, may be related to the depth D of the body of water 15 above the location 13A where an anchor pile (explained below) is to be disposed.

[0050] In FIG. 2, a length of pipe, for convenience referred to as a “drill string” 14, which may comprise threadedly coupled pipe segments is extended from a first hoisting unit 10A1 on the MODU, is extended into the water 15 toward the water bottom 13. The drill string 14 may include on its lower longitudinal end a drilling tool assembly called a “bottom hole assembly” (BHA) 12 that may be used to drill a hole (explained below) through formations (21 in FIG. 4) below the water bottom (13 in FIG. 1). FIG. 2A shows an enlarged view of the BHA 12, which may include, for example and without limitation, a drill bit 12A for drilling through the formations, one or more stabilizers 12B and segments of heavy weight drill pipe or drill collars 12C. The components in any particular implementation of a BHA may differ depending on the diameter of the hole to be drilled for an anchor pile to be inserted, the water depth and the formations 21 below the water bottom 13 to be drilled, among other parameters. The term “string” as used herein may mean, without limitation, a conduit or pipe that can be extended from and withdrawn onto the MODU 10. Where a hoist unit is described, the string may comprise segments of pipe connected end to end such as by threading to extend and withdraw the string. Spoolable tube such as coiled tubing may be used in some embodiments, depending on parameters such as the water depth (D in FIG. 1) and the length of a conduit used as an anchor pile (explained below).

[0051] FIG. 3 shows the BHA 12 drilling the formations 21 below the water bottom 13 while an anchor pile 16, e.g., in the form of a conductor pipe or similar conduit, is extended from a second hoist unit 10A2 on the MODU 10. While the present example embodiment is described in terms of a MODU having two independently operable hoist units 10A1, 10A2, it is to be clearly understood that a method according to the present disclosure may be implemented with any MODU having only a single hoist unit. In some embodiments using a MODU with a single hoist unit, it will be appreciated that before it is possible to extend the anchor pile 16 into the water, it would be necessary to move the drill string 14 and BHA 12 away from the drill center where the hole is drilled. Depending on the designed overall length of the anchor pile 16, the anchor pile 16 may be assembled from two or more threadedly connected segments (joints) of conduit coupled together end to end in a manner known to be used for assembling such conduit in a hoist unit.

[0052] Moving the drill string 14 and BHA 12 may be performed, e.g., by entirely withdrawing the drill string 14 and BHA 12 and storing it in the derrick 10A, or by using a cart or other transport device (not shown) to “hang off’ a substantial portion of the drill string 14 (i.e., so that it is suspended in the water below the MODU 10) and BHA 12 and moving the foregoing on the cart (not shown) laterally away from the drill center. The anchor pile 16 may then be extended from the single hoist unit. A length and diameter chosen for the anchor pile 16 may depend on, among other parameters, the required mooring force capacity of the anchor pile, the water depth and the characteristics of the formations below the water bottom 13.

[0053] FIG. 3 A shows an enlarged view of the BHA 12 as it drills the formations 21 below the water bottom 13. As will be appreciated by those skilled in the art, the BHA 12 is axially urged in the direction of drilling and is rotated, either by equipment on the first hoist unit 10A1 (or single hoist unit) such as a top drive or rotary table or by an hydraulic, pneumatic or electric motor to cause the drill bit 12A to cut through the formations 21 and lengthen a borehole (15 in FIG. 5).

[0054] FIG. 4 shows continuing drilling the formations 21 with the BHA 12 to a selected depth ID in the sub-bottom formations 21 while the anchor pile 16 continues to beextended from the MODU 10 by the second hoist unit 10A2. In some embodiments, a lower portion of the lower end of the anchor pile 16 may be radially expanded, e.g., flared, to provide increased resistance to the anchor pile 16 being pulled out of the formations 21 by reason of axial tension under mooring loads. In some embodiments and as shown in FIG. 4A, drilling the hole 15 can be in a direction deviated from vertical. Such deviating drilling may provide increased resistance to the anchor pile 16 being pulled out of the formations 21 by reason of axial tension under mooring loads. In some embodiments, and referring to FIG. 4B, the anchor pile 16 may be flared, as shown at 36. The flaring can be performed, e.g., using expanding tools or controlled explosive action.

[0055] FIG. 5 shows the MODU 10 retrieving the drill string 14 and BHA 12 from a hole 15 drilled through the formations 21 and into which the anchor pile 16 will be disposed. In the present example embodiment, retrieving the drill string 14 and BHA may be performed using the first hoist unit 10A1. The second hoist unit 10A2 is shown extending the anchor pile 16 simultaneously while the first hoist unit 10A1 retrieves the drill string 14 and the BHA 12. It will be appreciated by those skilled in the art that the foregoing implementation of a method using two hoisting units may be able to save considerable operating time by simultaneous retrieval of the drill string 14 and BHA 12 and extension of the anchor pile 16. It is to be understood, however that the illustrated example of a method explained herein is not a limitation on the scope of the present disclosure. In the embodiment shown in FIG. 5, after the drill string 14 is lifted enough to be fully removed from the hole 15, the MODU 10 may be moved such that the second hoist unit 10A2 is disposed approximately vertically over the hole 15, whereby extending the anchor pile 16 further will enable its insertion into the hole 15. In some embodiments, the MODU 10 may provide that the hoist units 10A1, 10A2 and the derrick 10A may be laterally displaced such that the second hoist unit 10A2 may be moved to the position of the hole 15 after the BHA 12 is withdrawn by the first hoist unit 10A1.

[0056] FIG. 6 shows the anchor pile 16 extended into the hole 15 drilled by the BHA (12 in FIG. 3 A). FIG. 6A shows an enlarged view of the upper end of the anchor pile 16, wherein a mooring cap 25 maybe attached to the upper end of the anchor pile 16. The mooring cap 25 may provide a connection feature (not shown) to attached a mooring lineor chain. The mooring cap 25 may be affixed to the upper end of the anchor pile 16 prior to running below the MODU 10, e.g., by welding. The mooring cap 25 may provide pass through of a sacrificial cementing line 27, which may be used for running the anchor pile 16 from the MODU 10 into the hole 15, pumping cement as will be explained below and release of a pipe string (see 16A in FIG. 6A) after cement is pumped through the anchor pile 16. It will be appreciated that if the anchor pile 16 is sufficiently long to require assembly of a plurality of pipe segments end to end, such assembly may also be required for the sacrificial cementing line 27. It should be noted that a sacrificial cementing line is not needed in all cases, cement could be poured from the top of anchor pile 16, but will enhance the quality of the cement job and increase the speed of the cementing operation.

[0057] FIG. 6A also shows internal reinforcement 23 that may be included in some embodiments of the anchor pile 16 to increase its capacity to sustain axial and bending load during use as a mooring connection point. FIG. 6B shows a sectional view of the anchor pile 16 inserted into the formation 21. The sacrificial cementing line 27 may be connected to the cementing string 16A by a running tool 16B of types known in the art.

[0058] FIGS. 6C through 6G, respectively, show various example embodiments of internal reinforcement for the anchor pile 16. The example embodiments include, for example and without limitation, respectively, T bars attached to the interior surface of the anchor pile 16, a pipe nested within the anchor pile and wherein the annular space so defined is filled with cement, filling the entire cross section of the anchor pile 16 with cement, larger wall thickness of the anchor pile, or reinforcement rods disposed inside the anchor pile 16. FIG. 6H shows a sectional view of the reinforcement disposed inside the anchor pile 16. The reinforcements may increase the local buckling strength of the anchor pile. 16. The global buckling strength is provided by the anchor pile 16 and soil (formation 13) interaction, where the local reinforcements may comprise a lesser role.

[0059] FIG. 7 shows the anchor pile 16 being inserted into the hole 15 prior to installation of cement. The conduit or pipe string (cementing string) 16A may be attached to the top of the anchor pile 16, e.g., as explained with reference to FIG. 6B, to extend further theanchor pile 16 from the MODU 10 once the full length of the anchor pile 16 is extended from the MODU 10.

[0060] FIG. 7A shows an enlarged view of the lower end of the anchor pile 16 shown in FIG. 7. The lower end may comprise a portion of the sacrificial cementing string 27 protruding from the bottom end of the anchor pile 16 to enable movement of cement into the hole 15 and ultimately into an annular space between the anchor pile 16 and the hole 15 during cementing operations. The annular space between the anchor pile 16 and the sacrificial cementing line 27 at the bottom end of the anchor pile 16 may be closed to prevent fluid and / or cement from entering the bottom of the anchor pile 16 during running in of the anchor pile 16 and cementing operations.

[0061] FIG. 8 shows the anchor pile 16 fully inserted into the hole (15 in FIG. 7A) at the end of the cementing string 16A. After the anchor pile 16 is fully inserted, cement may be pumped through the cementing string 16A. FIG. 8A shows an enlarged view of the upper end of the anchor pile 16 wherein may be observed the cementing string 16A coupled to the sacrificial cementing line 27. In some embodiments, the cementing string 16A and the sacrificial cementing line 27 may have approximately a same internal diameter, whereby a wiper plug (not shown) commonly used in well cementing operations may be pumped through both the cementing string 16A and the sacrificial cementing string 27 to fully displace cement from both the cementing string 16A and the sacrificial cementing line 27 and into the annular space (not shown) between the anchor pile 16 and the hole (15 in FIG. 7A).

[0062] FIG. 9 shows releasing the anchor pile 16 from the cementing string 16A after cement is cured. Release may be performed, e.g., by rotating the cementing string 16A in a direction (counterclockwise) counter to a thread engagement direction (clockwise) of the segments of the cementing string. By such rotation, connection between the running tool (16B in FIG. 6B) and the cementing string 16A may be released, and the cementing string 16A may be withdrawn onto the MODU 10. FIG. 9A shows an enlarged view of the upper end of the anchor pile 16 with the cementing string (16A in FIG. 9) detached as the anchor pile 16 will be placed into service as a mooring point.

[0063] FIG. 10 shows retrieving the cementing string 16A onto the MODU 10

[0064] FIG. 11 shows using a pipe string, e.g., the cementing string, a work string or a drill string, a line or a cable 31 to extend a mooring test line or chain 20 to engage the mooring cap (25 in FIG. 11A) at the upper end of the anchor pile 16. A crane or similar hoisting device on the MODU 10 may extend a line 28 attached to a remotely operated vehicle (ROV) cage 30A, to which is coupled an ROV (30 in FIG. 11 A). The line 28 may be extended into the water 13 to place the ROV 30 proximate the anchor pile and cap (25 in FIG. 11 A). The ROV (30 in FIG. 11 A) may effect connection of the mooring test chain 20 to the mooring cap (25 in FIG. 11 A). FIG. 11A shows an enlarged view of the mooring chain 20 being attached to the mooring cap 25 by, e.g., the remotely operated vehicle (ROV) 30.

[0065] FIG. 12 shows applying tension to the cementing string 16A to test the pull strength of the assembled mooring cap 25 and anchor pile 16. FIG. 12A shows an enlarged view of the chain 20 used to connect the mooring cap 25 to the work string or line 31 for the pull strength test.

[0066] It will be appreciated by persons skilled in the art that the anchor pile 16 in some embodiments may be outfitted with sensors, e.g., strain gauges, to determine stresses, orientations of stresses, strains and other useful information about the anchor pile during testing and during its lifetime. The signals from such sensors may be used for fatigue lifetime calculations, maintenance and other uses related to strain and changes in strain over time.

[0067] After the pull test is completed, the work string or line 31 may be retrieved onto the MODU 10. The MODU 10 may then be moved, e.g., to another location for an anchor pile and the process explained with reference to FIGS. 1 through 12A may be repeated.

[0068] When large mooring loads are expected, in some embodiments and referring to FIG. 13, a template 34, such as may comprise a steel or other high strength material frame, may comprise a plurality of openings to enable passage through each such opening of an anchor pile 16 as explained previously herein. Mooring load as may be communicatedthrough attached anchor chain 20 may be effectively distributed among the plurality of anchor piles 16, thus increasing the overall mooring capacity of the mooring station.

[0069] In some embodiments, and referring to FIG. 14, bending moment applied to the anchor pile 16 may be reduced by moving the attachment point of the anchor or mooring chain 20 to a position below the upper longitudinal end of the anchor pile 16. A slot 32 may be formed into the anchor pile longitudinally and extending to a selected attachment point 20A along the anchor pile. The mooring chain 20 may be extended through the slot vertically within the anchor pile 16, and caused to exit the anchor pile proximate the attachment point 20A. The attachment point 20A may comprise a pad eye (not shown) or other device to attach the mooring chain 20 at the attachment point 20A to the anchor pile 16. Thus, lateral mooring loads will effect lower bending moment on the anchor pile 16 than a top-attached mooring chain 20. A top view of the anchor pile 16 in FIG. 14B illustrates the slot 32. FIG. 14A shows the direction of mooring force applied to the anchor pile 16 by the slot and chain attachment as shown in FIG. 14.

[0070] In light of the principles and example embodiments described and illustrated herein, it will be recognized that the example embodiments can be modified in arrangement and detail without departing from such principles. The foregoing discussion has focused on specific embodiments, but other configurations are also contemplated. In particular, even though expressions such as in “an embodiment," or the like are used herein, these phrases are meant to generally reference embodiment possibilities, and are not intended to limit the disclosure to particular embodiment configurations. As used herein, these terms may reference the same or different embodiments that are combinable into other embodiments. As a rule, any embodiment referenced herein is freely combinable with any one or more of the other embodiments referenced herein, and any number of features of different embodiments are combinable with one another, unless indicated otherwise. Although only a few examples have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible within the scope of the described examples. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

Claims

AMENDED CLAIMS received by the International Bureau on 26 November 2024 (26.11 .2024)1. A method for setting an anchor pile, comprising: moving a mobile offshore drilling unit (MODU) in a body of water such that a first hoist unit associated with a derrick in the MODU is disposed over a water bottom location for setting the anchor pile; drilling a hole through the water bottom for receiving the anchor pile using a drill string and bottom hole assembly (BHA) extended from the first hoist unit; removing a drill string and bottom hole assembly (BHA) used to drill the hole; extending the anchor pile into the hole from a cementing pipe string using a second hoist unit spaced apart from the first hoist unit and associated with the derrick or a separate derrick on the MODU; pumping cement through the cementing string and through the anchor pile; disconnecting the cementing string from the anchor pile; and after the cement is cured, applying tension from a line or string extended from the MODU to test mooring strength of the anchor pile.

2. The method of claim 1 wherein the anchor pile is extended into the hole by removing the BHA from the hole, moving the MODU such that the second hoist unit and the extended cementing string and anchor pile are disposed over the hole, and extending the anchor pile into the hole.

3. The method of claim 1 wherein the disconnecting the cementing string comprises rotating the cementing string to unthread a threaded connector disposed between the cementing string and the sacrificial cementing line.

4. The method of claim 1 wherein the applying tension comprises extending a line or chain from the MODU, connecting the line or chain to a mooring cap disposed on an upper end of the anchor pile, and withdrawing the line or chain using the MODU.

5. The method of claim 1 further comprising reinforcing the anchor pile by installing at least one type of reinforcement to an interior of the anchor pile.

6. The method of claim 5 wherein the at least one type of reinforcement comprises at least one of, T bars, a pipe nested in the anchor pile wherein an annular space between the nested pipe and the anchor pile is filled with cement, reinforcing rods, or filling an interior of the anchor pile with cement.

7. The method of claim 5 wherein the anchor pile is provided with slot to allow a chain to pass through.

8. The method of claim 7 wherein the slot extends longitudinally to an exit point below an upper longitudinal end of the anchor pile.

9. The method of claim 7 wherein a mooring chain is fixedly connected to the anchor pile proximate the exit point.

10. The method of claim 9_wherein the mooring chain is extended outside of the anchor pile and pulled sideways before the pumping cement.

11. The method of claim 1 wherein the anchor pile comprises a sacrificial cementing line extending longitudinally therethrough and nested within the anchor pile.

12. An anchor pile for water bottom mooring attachment, comprising: a conduit; a mooring cap attached to an end of the conduit, the mooring cap having an opening for passage therethrough of a cementing line, the mooring cap having a feature for attachment of a mooring line; and wherein the cementing line is nested within and extends past the end of the conduit and past an opposed end of the conduit, the cementing line comprising a running tool at one end having a coupling enabling releasable connection to a pipe string extending from a drilling unit on a surface of a body of water.

13. The anchor pile of claim 12 further comprising a reinforcement disposed in an interior of the conduit.

14. The anchor pile of claim 13 wherein the reinforcement comprises at least one of T bars, a pipe nested in the conduit wherein an annular space between the nested pipe and the conduit is filled with cement, reinforcing rods, or filling an interior of the conduit with cement.

15. The anchor pile of claim 12 wherein an annular space between the cementing line and the conduit is closed at a longitudinal end of the conduit opposed to the mooring cap.

16. The anchor pile of claim 12 further comprising a longitudinally extending slot for attaching an anchor chain or line at a longitudinal position below a top longitudinal end of the anchor pile.

Citation Information

Patent Citations

  • Drilled anchor pile

    WO2023031576A1

  • Anchor systems and methods

    US20230415853A1