EP2200894A2

EP2200894A2 - Jet implanted anchor

Info

Publication number: EP2200894A2
Application number: EP08840978A
Authority: EP
Inventors: Iii Edward E. Horton
Original assignee: HORTON DEEPWATER Dev SYSTEMS Inc
Current assignee: HORTON DEEPWATER Dev SYSTEMS Inc
Priority date: 2007-10-26
Filing date: 2008-10-27
Publication date: 2010-06-30
Also published as: CN101835682A; EP2200894A4; BRPI0818768A2; US20090107387A1; WO2009055789A2; WO2009055789A3

Abstract

A jet implanted anchor. In some embodiments, the anchor includes a tubular member having a plurality of pivotable flukes coupled thereto. Each pivotable fluke is moveable between a collapsed position, wherein the pivotable fluke abuts the tubular member, and an extended position, wherein the pivotable fluke is angularly offset from the tubular member. In other embodiments, the anchor includes a plate coupled along its perimeter to a tubular member. The tubular member includes at least one inlet, a plurality of nozzles, and a flowbore extending therebetween. The anchor further includes a swivel connection coupled between a pipe connector and the tubular member. The swivel connection is rotatable about the tubular member and provides fluid communication between the swivel connection and the tubular member. The pipe connector selectably limits rotation of the swivel connection about the tubular member and fluid communication between the pipe connector and the swivel connection.

Description

JET IMPLANTED ANCHOR

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0001] Not applicable.

BACKGROUND OF THE INVENTION

[0002] Embodiments of the invention relate to anchors for mooring vessels. More particularly, embodiments of the invention relate to a novel system and method for securing a vessel in position using an anchor implanted into the seafloor by jetting.

[0003] Existing systems and associated methods for mooring vessels used in offshore drilling and production operations are numerous and diverse. The systems include drag anchors, gravity anchors, suction pile drilled in anchors, driven piles, and steel plates pushed into the seafloor by a suction pile. All have their associated advantages and disadvantages, depending on water depth, soil characteristics, operational requirements and available installation equipment. For instance, conventional anchors used on ships do not have sufficient holding capacity, or bearing strength, when positioned in soft, sedimentary soil, like that found in the Gulf of Mexico. High capacity drag anchors are difficult to set in deep water because these anchors have to be dragged horizontally with great force in order to implant the anchors to depths where the soil is competent. Such operations are difficult and very costly in water deeper than 3,000 feet. Gravity anchors are expensive and difficult to install. For these reasons, they have not been used in the Gv₁If of Mexico. Driven piles have been used for mooring spars in the Gulf of Mexico. However, the pile drivers have depth limitations. Also, both the pile driving equipment and support vessel are costly. Suction piles and suction caissons for setting anchors are the most promising methods of setting anchors in deepwater regions of the Gulf of Mexico. While they have been used and found to work satisfactorily, experience with these systems is limited. Further, the depth to which suction piles may be driven in is limited to 100 feet.

[0004] Thus, the embodiments of the invention are directed to deepwater anchors that seek to overcome these and other limitations of the prior art.

SUMMARY OF THE PREFERRED EMBODIMENTS

[0005] A jet implanted anchor and associated methods are disclosed. In some embodiments, the anchor includes a tubular member having a plurality of pivotable flukes coupled thereto. Each pivotable fluke is moveable between a collapsed position, wherein the pivotable fluke abuts the tubular member, and an extended position, wherein the pivotable fluke is angularly offset from the tubular member.

[0006] In other embodiments, the anchor includes a plate coupled along its perimeter to a tubular member. The tubular member includes at least one inlet, a plurality of nozzles, and a flowbore extending therebetween. The anchor further includes a swivel connection coupled between a pipe connector and the tubular member, The swivel connection is rotatable about the tubular member and provides fluid communication between the swivel connection and the tubular member. The pipe connector selectably limits rotation of the swivel connection about the tubular member and fluid communication between the pipe connector and the swivel connection.

10007] Some methods for mooring a vessel over a seafloor using the anchor include coupling the anchor to a fluid source, injecting fluid from the fluid source into the anchor, and ejecting fluid from the anchor, whereby the ejected fluid displaces soil in the seafloor, whereby the anchor is jetted into the seafloor.

[0008J Thus, the jet implanted anchor includes a combination of features and advantages that enable it to moor vessels in deep water. These and various other characteristics and advantages of the preferred embodiments will be readily apparent to those skilled in the art upon reading the following detailed description and by referring to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] For a detailed description of the preferred embodiments of the invention, reference will now be made to the accompanying drawings in which:

[0010] Figure 1 is a schematic representation of a jet implanted anchor in accordance with the principles disclosed herein;

[0011] Figure 2 is an enlarged view of the jet pipe connection and the jet pipe swivel of the jet implanted anchor of Figure 1;

[0012] Figures 3 through 5 illustrate installation of the jet implanted anchor of Figure 1 ;

[0013] Figure 6 is a schematic representation of another embodiment of a jet implanted anchor;

[0014] Figures 7 and 8 are schematic representations of an embodiment of a jet implanted anchor having extendable curved flukes in collapsed and extended positions, respectively; [0015] Figure 9 is a schematic representation of an embodiment of a jet implanted anchor having staggered flukes in their extended positions;

[0016] Figure 10 is a schematic representation of an embodiment of a jet implanted anchor having aligned flukes in their extended positions;

[0017] Figure 11 is a schematic representation of an embodiment of a jet implanted anchor having staggered flukes which pivot approximately 45 degrees between their collapsed and extended positions;

[0018] Figure 12 is an enlarged, schematic representation of the staggered flukes of the jet implanted anchor of Figure 11; and

[0019] Figures 13A and 13B are cross- sectional views of a jet implanted anchor with having flukes locked in their collapsed positions and unlocked to allow them to assume their extended positions.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0020] Various embodiments of the invention will now be described with reference to the accompanying drawings, wherein like reference numerals are used for like parts throughout the several views. The figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form, and some details of conventional elements may not be shown in the interest of clarity and conciseness. [0021] In the following discussion and in the claims, the terms "including" and "comprising" are used in an open-ended fashion, and thus should be interpreted to mean "including, but not limited to...". Also, the terms "couple," "couples", and "coupled" used to describe any connections are each intended to mean and refer to either an indirect or a direct connection, [0022] The preferred embodiments of the invention relate to anchors for mooring vessels in deep water. The invention is susceptible to embodiments of different forms. There are shown in me drawings, and herein will be described in detail, specific embodiments of the invention with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention and is not intended to limit the invention to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results.

[0023] Referring to Figure 1, an embodiment of a jet implanted (JIP) anchor 100 is shown. JIP anchor 100 includes a plate 105 having a perimeter defined by a lower end 115, two opposing sides 120, and an upper end 125. Anchor 100 further includes jet pipe 110 coupled to and extending along at least a portion of the perimeter of plate 105. Jet pipe 110 is a tubular member or piping having a fiowbore 112 (Fig. 2) therethrough, a plurality of nozzles 130 disposed along its length, and one or more inlet ports 170 (Fig. 2). Inlet ports 170 and fiowbore 112 of jet pipe 110 enable fluid communication between nozzles 130 and jet swivel 135, as will be described.

[0024] In this exemplary embodiment, plate 105 is substantially rectangular and includes jet pipe 110 along its entire perimeter. Also, inlet ports 170 are located in jet pipe 110 proximate upper end 125 of plate 105. In other embodiments, plate 105 may have another shape, e.g., triangular, and/or include jet pipe 110 along one or more of lower end 115, sides 120, and upper end 125. Further, as shown in Figure I₃ nozzles 130 are essentially equally spaced openings or ports through the wall of jet pipe 110. In other embodiments, each nozzle 130 may be formed by a tubular extension coupled over an opening or port in jet pipe 110 (see Fig. 6). Also, nozzles 130 may be positioned along jet pipe 110 with unequal or nonuniform spacing to promote jetting in of anchor 100.

[0025] Anchor 100 further includes a jet pipe swivel 135 coupled between a jet pipe connector 140 and jet pipe 110 at upper end 125 of plate 105. Referring now to Figure 2, a jet pipe swivel 135 and a jet pipe connector 140 are depicted with swivel 135 in partial cross- section to expose the sealed couplings of jet pipe connector 140 within swivel 135 and jet pipe 110 within swivel 135. Jet pipe connector 140 enables coupling of a jetting riser 225 (Figs. 1, 3) to anchor 100 for installation of anchor 100 and disconnection of jetting riser 225 from anchor 100 when installation is complete, as will be described. In some embodiments, jet pipe connector 140 also enables coupling a mooring line to anchor 100.

[0026] Jet pipe connector 140 also provides fluid communication between jetting riser 225 and anchor 100, or more specifically, jet swivel 135 of anchor 100. To enable fluid communication between jetting riser 225 and jet swivel 135, jet pipe connector 140 includes a tubular body 142 coupled to jetting riser 225. Tubular body 142 has a fiowbore 144 extending therethrough and in fluid communication with jetting riser 225. Jet pipe connector 140 further includes a plurality of outlet ports 146 spaced circumferentially about tubular body 142. During jetting in of anchor 100, as will be described, fluid is injected through jetting riser 225 to anchor 100. The injected fluid passes from jetting riser 225 through fiowbore 144 of jet pipe connector 140 and exits jet pipe connector 140 through ports 146. [0027] Jet pipe swivel 135 provides a rotatable coupling between anchor 100 and jetting riser 225, and fluid communication between jet pipe connector 140 and jet pipe 110. To provide rotation of anchor 100 relative to jetting riser 225, jet pipe swivel 135 includes one or more sleeves 145 rotatably coupled about jet pipe 110, a tubular receptacle 150 for receiving jet pipe connector 140 and coupling the two components 140, 145, and two tubular extensions 152 coupled therebetween. In this exemplary embodiment, two jet swivel sleeves 145 are rotatably coupled to jet pipe 110 proximate upper end 125 (Fig. 1) of plate 105. Also, jet pipe swivel 135 and jet pipe connector 140 are coupled via mating threads 154 formed on the inner and outer surfaces of receptacle 150 and jet pipe connector 140, respectively, In other embodiments, however, jet pipe swivel 135 and jet pipe connector 140 may be coupled via another equivalent type of connection known in the industry, such as but not limited to a J-slot connection.

[0028] To enable fluid communication between jet pipe connector 140 and jet pipe 110, tubular receptacle 150 includes two inlet ports 156, and each tubular extension 152 includes a flowbore 162 extending therethrough. When jet pipe connector 140 is inserted within and coupled to receptacle 150 such that outlet ports 146 of jet pipe connector 140 substantially align with inlet ports 156 of tubular receptacle 150, as shown, fluid communication is provided between jet pipe connector 140 and jet pipe 110. Two sealing members 158 are disposed on opposite sides of ports 144, 156 in sealing engagement between jet pipe connector 140 and tubular receptacle 150. In some embodiments, sealing members 158 arc O-rings. Fluid exiting ports 146 of jet pipe connector 140, as described above, is forced through inlet ports 156 of tubular receptacle 150 of jet swivel 135. The fluid then flows from inlet ports 156 through flowbores 162 toward jet swivel sleeves 145. Upon exiting flowbores 162 within jet swivel sleeves 145, the fluid is forced through inlet ports 170 of jet pipe 110 by virtue of sealing members 164 disposed on opposite sides of each port 170 in sealing engagement between jet swivel sleeve 145 and jet pipe 110. In some embodiments, sealing members 164 are O-iϊngs. From inlet ports 170, the fluid passes through flowbore 112 of jet pipe 110 to exit anchor 100 via nozzles 130 (Fig. 1). Fluid exiting nozzles 130 enables jetting in of anchor 100 during installation. [0029] Jet pipe connector 140 is extendable to engage and couple with anchor plate 105 to prevent rotation of anchor 100 relative to jetting riser 225. The extended position is the configuration assumed by jet pipe connector 140 during jetting in of anchor 100. In some embodiments, including those illustrated by Figure 2, jet pipe connector 140 is extendable to engage plate 105 such that the lower end of 148 of jet pipe connector 140 is threaded into a bore 107 in plate 105. Jet pipe connector 140 is in its extended position in Figure 2. In this position, jet pipe connector 140 prevents anchor plate 105 from rotating relative to jetting riser 225. As such, plate 105 remains substantially parallel to jetting riser 225, and more importantly, substantially normal to the seafloor during jetting in. This facilitates installation of anchor 100 because less force is required to implant anchor 100.

[0030] Jet pipe connector 140 is also retractable to disengage from anchor plate 105 to allow rotation of anchor 100 relative to jetting riser 225. In some embodiments, including those illustrated by Figure 2, jet pipe connector 140 is retractable to disengage its lower end 148 from bore 107 of plate 105. This retracted position is the configuration assumed by jet pipe connector 140 after jetting in of anchor 100 is complete. In this position, anchor 100 is rotatable relative to jetting riser 225, for purposes described below.

[0031] Referring again to Figure 1, anchor 100 further includes a plurality of anchor reins 155 and a mooring line connector 160. Each rein 155 is coupled between different regions of a face 165 of anchor plate 105 and mooring line connector 160. Prior to installation of anchor 100, a mooring line is coupled between a vessel to be secured in position by anchor 100 and connector 160. After anchor 100 has been installed, load from the vessel is then transferred through the mooring line, connector 160, and reins 155 to plate 105. The positioning and length of reins 155 is selected such that when load from the vessel is transferred to anchor 100 in this manner, plate 105 remains substantially normal to the mooring line. As such, anchor 100 is oriented to provide maximum bearing strength to resist the vessel load. The positioning and/or length of reins 155 may be selected as a function of the expected angle between the mooring line and the seafloor 230 when anchor 100 is installed.

[00321 Figures 3 through 5 illustrate an exemplary system and method for securing a vessel 200 in position with a mooring system 205 including anchor 100. Beginning with Figure 3, vessel 200 includes a drilling and/or production rig 210, a pump 215 and a hoist 220 positioned thereon. Jetting riser 225 is suspended from vessel 200 over the seafloor 230. Anchor 100 is coupled to jetting riser 225 via jet pipe connector 140, as previously described. Mooring system 205 further includes a mooring line 235 coupled between hoist 220 and mooring line connector 160 of anchor 100.

[0033] Vessel 200 is initially positioned in the desired location for mooring. Anchor 100 is lowered toward the seafloor 230 via jetting riser 225. Jet pipe connector 140 of anchor 100 is extended within jet swivel 135 to engage anchor plate 105 and prevent rotation of anchor 100 relative to jetting riser 225, as described above. Also, extension of jet pipe connector 140 enables ports 146 of jet pipe connector 140 to substantially align with ports 156 of jet swivel 135, thereby providing a fluid path between jetting riser 225 and anchor 100, also as described above. As anchor 100 approaches the seafloor 230, pump 215 is activated to deliver seawater through jetting riser 225 to anchor 100. The seawater flows from jetting riser 225 through jet pipe connector 140 and jet swivel 135 into jet pipes 110, eventually exiting anchor 100 via nozzles 130.

[0034] Referring now to Figure 4, when anchor 100 reaches the seafloor 230, seawater exiting nozzles 130 cuts a path through the surrounding soil, enabling anchor 100 to be jetted into the seafloor 230. Jetting in of anchor 100 in this manner enables anchor 100 to be implanted to the desired depth with less force from jetting riser 225 than would otherwise be necessary, and to greater depths than would otherwise be possible. After anchor 100 reaches the desired depth, pump 215 is turned off, and seawater ceases to be injected through jetting riser 225 to anchor 100.

[0035] Next, jet pipe connector 140 is retracted relative to plate 105 to allow anchor 100 to be rotatable relative to jetting riser 225. A compression load is then applied via jetting riser 225 to anchor 100 to rotate anchor 100 relative to jetting riser 225 such that anchor 100 is no longer substantially normal to the seafloor 230, but rather is oriented at an angle relative to the seafloor 230. In its rotated orientation, anchor 100 is preferably oriented such that plate 105 is substantially normal to the expected position which mooring line 235 will assume when jetting riser 225 is disconnected from anchor 100 and vessel 200 is secured in position by mooring line 235.

[0036] Jetting riser 225 is then disconnected from jet pipe connector 140, as illustrated by Figure 5. Vessel 200 remains secured in positioned by mooring system 205. Load from vessel 200 is transferred to anchor 100 via mooring line 235. Because anchor 100 is oriented substantially normally to mooring line 235, anchor 100 provides maximum bearing strength to resist the vessel load and remain implanted. In the event that it becomes desirable to later retrieve anchor 100, jet pipe connector 140 provides a coupling means to enable anchor 100 to be pulled from its implanted location.

[0037] Figure 6 depicts another embodiment of a jet implanted anchor. Anchor 300 is structurally similar to anchor 100 with the following differences. Anchor 300 includes a plate 305 that is nonrectangular in shape, having an angular lower end 315 that enables anchor 300 to be more easily implanted in the seafloor 230. Further, plate 305 includes a plurality of stiffening plates or ribs 370 spanning plate 305 from side 120 to side 120. Ribs 370 promote the structural integrity of plate 305, and thus the bearing capacity of anchor 300. Anchor 300 includes a plurality of nozzles 330 that are essentially tubular extensions coupled to lower end 315 of plate 305. In alternative embodiments, nozzles 330 may be formed integrally with plate 305. Finally, anchor 300 does not include anchor reins 155 and mooring line connector 160, as does anchor 100. Instead, anchor 300 includes a plate 375 extending substantially normally from face 165 of plate 305. Plate 375 includes a bore 380 that enables coupling of mooring line 230 thereto. Aside from these differences, anchor 300 is substantially similar to anchor 100 in structure, installation, and operation.

[0038] Both anchors 100, 300 are jetted into the seafloor 230 in substantially vertical orientations relative to the seafloor 230 in order to minimize the amount of force required to implant anchors 100, 300 to the desired depth. After jetting in, anchors 100, 300 are then rotated to orient plates 105, 305 substantially normally to the expected load direction, or mooring line 230, in order to enable anchors 100, 300 to provide maximum bearing capacity. In other embodiments of a jet implanted anchor, rotation of the anchor after jetting in is not necessary to maximize the bearing capacity of the anchor. Instead, the bearing capacity is promoted by extending pivotable flukes to increase the surface area of the anchor normal to the load direction.

[0039] Turning now to Figures 7 and 8, an embodiment of a jet implanted anchor having pivotable flukes in collapsed and extended positions, respectively, is depicted. Anchor 400 includes a tubular member or body 405 and a plurality of pivotable flukes 410 coupled thereto. Tubular body 405 includes a lower end 415, an upper end 420, and a flowbore 425 extending therebetween. Each fluke 410 is coupled to tubular body 405 by two pins 430, each pin 430 inserted through fluke 410 and body 405 on substantially opposite sides of body 405 and secured by, for example, a nut (not shown), Pins 430 enable pivotable movement of each fluke 410 relative to body 405 between a collapsed position, where fluke 410 is collapsed against body 405 as shown in Figure 7, and an extended position, where fluke 410 is pivoted away from body 405 approximately 90 degrees as shown in Figure 8.

[0040] To install anchor 400, anchor 400 is coupled to jetting riser 225 and mooring line 235 (see Fig. 11) with each fluke 410 in its collapsed position. Anchor 400 is then lowered toward the seafloor 230 via jetting riser 225. As anchor 400 approaches the seafloor 230, pump 215 is activated to deliver seawater through jetting riser 225 to anchor 400. The seawater flows from jetting riser 225 through flowbore 425 of body 405 and exits body 405 at its lower end 415. In this way, lower end 415 functions as a nozzle, not unlike nozzles 130, 330 of anchors 100, 300. When anchor 400 reaches the seafloor 230, seawater exiting body 405 cuts a path through the surrounding soil, enabling anchor 400 to be jetted into the seafloor 230. Jetting in of anchor 400 in this manner enables anchor 400 to be implanted to the desired depth with less force from jetting riser 225 than would otherwise be necessary, and to greater depths than would otherwise be possible. Further, because flukes 410 are in their collapsed positions against body 405, flukes 410 provide minimal resistance to implantation of body 405. This too reduces the amount offeree needed to implant anchor 400 to the desired depth.

10041] After anchor 400 is implanted to the desired depth, jetting of seawater through anchor 400 is terminated. A tension load is then applied to anchor 400 via jetting riser 225 to open or extend flukes 410. More specifically, a tension load is applied to jetting riser 225 causing jetting riser 225 to "lift" anchor 400 some distance. The upward movement of anchor 400, in turn, causes each fluke 410 to react against the surrounding soil and pivot from its collapsed position to its extended position. Once flukes 410 are extended, anchor 400 is set. [0042] Jetting riser 225 is then disconnected from anchor 400. Vessel 200 is then secured in position by mooring line 230 coupled to anchor 400. Load from vessel 200 is transferred to anchor 400 via mporing line 230. Due to the increased surface area of anchor 400 normal to the load direction provided by extended flukes 410, anchor 400 enables maximum bearing strength to resist the vessel load.

[0043] hi the embodiment described in reference to and shown in Figures 7 and 8, flukes 410 are coupled to body 405 such that, proceeding along the length of body 405 from either end 415, 420, each successive fluke 410 is circumferentially offset 45 degrees relative to the preceding fluke 410. In other embodiments, flukes 410 may be circumferentially positioned about body 405 with different degrees of offset. For example, flukes 410 may be staggered along the length of body 405 such that each successive fluke 410 is circumferentially offset 180 degrees relative to the preceding fluke 410, as shown in Figure 9, Alternatively, each successive fluke 410 may not be circumferentially offset from the preceding fluke 410. In other words, flukes 410 may be aligned, as shown in Figure 10.

[0044] Additionally, flukes 410 may have varied shapes from one embodiment of a jet implanted anchor to the next. In Figures 7-10, flukes 410 are essentially rectangular in shape. However, in other embodiments, including those illustrated by Figure 11, flukes 410 may be triangular, for example. Further, flukes 410 may be curved, as shown in Figures 7 and 8, or flat, as shown in Figures 9-11. [0045] Still further, flukes 410 may be pivotable over a range of approximately 90 degrees between collapsed and extended positions, as shown in Figures 7-10, or pivotable over a smaller range. Figure 11, for example, depicts anchor 400 having flukes 410, wherein each fluke 410 pivots approximately 45 degrees between its extended position, as shown, and its collapsed position (see Fig. 12). To limit pivoting of flukes 410 to no more than 45 degrees, each fluke 410 includes a curved member 505 extending therefrom proximate pins 430. Referring to Figure 12, each curved member 505 is shaped to receive tubular body 405. Thus, when flukes 410 pivot about pins 430 from their collapsed positions, as shown in Figure 12, to their extended positions, as shown in Figure 11, pivoting movement of each fluke 410 ceases when its curved member 505 abuts tubular body 405. These variables, meaning fluke size, pivot range, and shape, as well as length and width enable the JIP anchor capacity to be optimized depending on the soil properties expected for locations where the anchor may be used.

[0046] During installation of a jet implanted anchor having pivotable flukes, it may be desirable to work the anchor into the seafloor 230 to the desired depth by repeatedly lifting and dropping the anchor, the latter action taking advantage of the anchor weight to assist implantation of the anchor. Until the anchor reaches the desired depth, it is preferred that its flukes remain in their collapsed positions abutting the tubular body of the anchor and not extend as the anchor is repeatedly lifted, To enable the flukes to remain collapsed against the tubular body of the anchor, some embodiments of the anchor further include a plurality of locking devices coupled to the flukes.

[0047] Turning finally to Figures 13A and 13B, an embodiment of a jet implanted anchor having a locking device coupled to each fluke is depicted. Anchor 600 includes tubular body 405 with a plurality of pivotable flukes 410 coupled thereto. Each fluke 410 is coupled to tubular body 405 by two threaded screws 630, each screw 630 inserted through a threaded bore 634 in fluke 410 and a bore 636 in body 405 on substantially opposite sides of body 405 and secured by, for example, a threaded nut 632. Screws 630 with flukes 410 coupled thereto are røtatable within bores 636 of body 405. Due to the threaded coupling of screws 630 and flukes 410, flukes 410 do not pivot relative to body 405 unless screws 630 rotate within bores 636 of body 405.

[0048] Anchor 600 further includes a plurality of locking devices 640, each locking device 640 coupled to a different fluke 410 via at least one of the screws 630 threadably engaging the fluke 410. Each locking device 640 is selectably actuatable from a locked position (Fig. 13A), wherein the screw(s) 630 coupled thereto is prevented from rotating within bore 636 of body 405, to an unlocked position (Fig. 13B), wherein the screw(s) 630 is free to rotate within bore 636. In some embodiments, locking devices 640 are electrically actuated to unlock via a power source (not shown) coupled thereto and extending from vessel 200 through jetting riser 225. [0049] Prior to installation of anchor 600, flukes 410 are collapsed against body 405 and locking devices 640 are configured to their locked positions, wherein screws 630 may not rotate relative to bores 636 of body 405. Thus, flukes 410 may not pivot relative to body 405, and are locked in their collapsed positions, as illustrated by Figure 13 A. Anchor 600 is then lowered toward the seafloor 230 via jetting riser 225 and installed, as described above. When anchor 600 has been implanted to the desired depth, locking devices 640 are actuated to their unlocked positions, thereby allowing screws 630 to rotate relative to body 405 and flukes 410 to extend. Anchor 600 is then lifted to a degree to extend flukes 410. The upward movement of anchor 600, in turn, causes each fluke 410 to react against the surrounding soil and pivot from its collapsed position to its extended position, as illustrated by Figure 13B. Once flukes 410 are extended, anchor 600 is set.

[0050] Jet implanted anchors in accordance with the principles disclosed herein arc useful for mooring vessels during offshore drilling and production operations for at least a number of reasons. JIP anchors enable mooring in the deep waters where the upper section of the seafloor includes sedimentary soils that are amenable to jetting. JIP anchors can be quickly and easily jetted into the seafloor to the desired depth because the cross-sectional area of the anchors can be minimized by orienting the anchor in a particular manner or by collapsing their pivotable flukes. Once implanted, JIP anchors have high bearing capacity over a wide range of mooring line angles from horizontal to vertical because the cross-sectional area of the anchors normal to the mooring line can be maximized either by orienting the anchor in a particular manner or by extending their pivotable flukes.

[0051] While some embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems are possible and are within the scope of the invention. For example, the relative dimensions of various parts, the materials from which the various parts are made, and other parameters can be varied.

Claims

CLAIMSWhat is claimed is:

1. An anchor for mooring a vessel, the anchor comprising: one or more fluid flowpaths extending therethrough, each flowpath having an inlet and an outlet.

2. The anchor of claim 1 , further comprising a nozzle at each outlet.

3. The anchor of claim 2, further comprising a tubular member having one or more flowbores, wherein the tubular member defines the one or more fluid flowpaths.

4. The anchor of claim 3, wherein each nozzle is coupled to the tubular member.

5. The anchor of claim 3, wherein each nozzle is formed integrally with the tubular member.

6. The anchor of claim 3, wherein the tubular member further comprises: a plurality of pivotable flukes coupled thereto; wherein each pivotable fluke is moveable between a collapsed position, wherein the pivotable fluke abuts the tubular member, and an extended position, wherein the pivotable fluke is angularly offset from the tubular member to a degree.

7. The anchor of claim 6, wherein the degree is no greater than ninety degrees.

8. The anchor of claim 6, wherein the plurality of pivotable flukes are circumferentially aligned along the tubular member.

9. The anchor of claim 6, wherein the plurality of pivotable flukes are circumferentially staggered along the tubular member, wherein adjacent pivotable flukes are circumferentially offset by an angle no greater than 90 degrees.

10. The anchor of claim 6, wherein each pivotable fluke is coupled to the tubular member by two pinned connections.

11. The anchor of claim 6, further comprising a plurality of locking devices coupled to the plurality of flukes and configured to limit pivoting of the plurality of flukes.

12. The anchor of claim 11, wherein each of the plurality of locking devices is selectably actuatable from a locked position, wherein each of the plurality of flukes is prevented from pivoting, and an unlocked position, wherein each of the plurality of flukes is free to pivot.

13. The anchor of claim 3 , further comprising: a first plate coupled along its perimeter to the tubular member; a swivel connection coupled to the tubular member, the swivel connection configured to rotate about the tubular member and to provide fluid communication between the swivel connection and the tubular member.

14. The anchor of claim 13, further comprising: a pipe connector coupled to the swivel connection, the pipe connector configured to selectably limit rotation of the swivel connection about the tubular member and to selectably permit fluid communication between the pipe connector and the swivel connection.

15. The anchor of claim 14, further comprising: a second plate coupled to the first plate, wherein the second plate extends substantially normally from the first plate and has a bore therethrough,

16. The anchor of claim 14, further comprising : a mooring line connector configured to enable coupling of a mooring line thereto; and a plurality of reins, each rein coupled between the mooring line connector and the first plate.

17. The anchor of claim 16, wherein each rein is coupled to the first plate at a location and has a length, the location and the length selected to maintain the first plate substantially normal to the mooring line when tensioned by a vessel,

18. A mooring system for securing a vessel in position over a seafloor, the mooring system comprising: an anchor having one or more fluid flowpaths extending therethrough, each fluid flowpath having an inlet and an outlet; and a mooring line coupled between the anchor and the vessel.

19. The mooring system of claim 18, wherein the anchor is configured to selectably receive fluid through the inlets, convey the fluid along the one or more flowpaths, and eject the fluid through the outlets.

20. The mooring system of claim 19, wherein the anchor further comprises a nozzle at each outlet.

21. The mooring system of claim 18, wherein the anchor is configured to couple with a fluid source.

22. The mooring system of claim 21 , wherein the fluid source is a j etting riser suspended by the vessel.

23. The mooring system of claim 21, wherein the anchor is selectably rotatable relative to the fluid source.

24. The mooring system of claim 23, wherein the anchor is rotatable relative to the fluid source after the anchor is implanted below the seafloor to a desired depth and rotatably fixed relative to the drilling source during implantation of the anchor into the seafloor.

25. The mooring system of claim 18, wherein the anchor comprises: a tubular body; and a plurality of pivotable flukes; wherein each pivotable fluke is moveable between a collapsed position, wherein the pivotable fluke abuts the tubular body, and an extended position, wherein the pivotable fluke is angularly offset from the tubular body to a degree.

26. A method for mooring a vessel over a seafloor, the method comprising: coupling an anchor to a fluid source, the anchor comprising: one or more fluid flowpaths extending therethrough, each fluid flowpath having an inlet and an outlet; injecting fluid from the fluid source into the inlets of the anchor; and ejecting fluid through the outlets of the anchor, whereby the ejected fluid displaces soil in the seafloor, whereby the anchor is jetted into the seafloor.

27. The method of claim 26, further comprising: discontinuing the injecting of fluid; and applying a compression load to the anchor to rotate the anchor, whereby, once rotated, the anchor is substantially normal to a mooring line coupled between the anchor and the vessel.

28. The method of claim 27, wherein, during the ejecting fluid, the anchor is prevented from rotating relative to the fluid source.

29. The method of claim 26, wherein the anchor further comprising: discontinuing the injection of fluid into the anchor, the anchor comprising: a tubular body; and a plurality of pivotable flukes, wherein each pivotable fluke is moveable between a collapsed position, wherein the pivotable fluke abuts the tubular body, and an extended position, wherein the pivotable fluke is angularly offset from the tubular body; and applying a tension load to the anchor to lift the anchor, whereby each pivotable fluke moves from its collapsed position to its extended position.

30. The method of claim 29, wherein the applying a tension load comprises lifting the anchor.

31. The method of claim 29, further comprising preventing the plurality of flukes from extending during the ejecting fluid.