US3330338A

US3330338A - Anchor and method of installing

Info

Publication number: US3330338A
Application number: US334812A
Authority: US
Inventors: James R Dozier
Original assignee: Shell Oil Co
Current assignee: Shell USA Inc
Priority date: 1963-12-31
Filing date: 1963-12-31
Publication date: 1967-07-11
Anticipated expiration: 1984-07-11

Description

July 11, 1967 J. R. DOZIER 3,330,338

ANCHOR AND METHOD OF INSTALLING Filed Dec. 31, 1963 i I FIG. I as I8 i iii l4 M II '.'I INVENTOR: V/ i fio (1 15!. I J. R. DOZIER BY 14 t e HIS AGENT United States Patent 3,330,338 ANCHOR AND METHOD OF INSTALLING James R. Dozier, Whittier, Calif, assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware Filed Dec. 31, 1963, Ser. No. 334,812 17 Claims. (Cl. 166.5)

The present application is a continuation-in-part application of copending patent application Serial No. 157,654 which was filed on December 7, 1961, and is now Patent No. 3,221,816.

This invention relates to an anchor adapted to secure an anchor line at or near the ocean floor, and pertains more particularly to an anchor adapted to be sunk in the ocean floor and left there in the event that it is necessary to disconnect the anchor line and move an anchored vessel or other structure to another location.

To date, oil and gas wells have been drilled at offshore locations from fixed platforms or from floating or submersible barges. At the conclusion of the well drilling operations, the well equipment and the Christmas tree attached to the top thereof extends above the surface of the water where it was common to surround it by a platform which would be fixedly supported from the ocean floor. In remote locations, the production facilities, such as an oil and metering and storage tanks, were mounted on the platform at the well and the production fluid from the well Was run into these lines. In highly developed fields, a centralized production facility for handling a number of wells would be constructed on piles sunk in the ocean floor at a centrally-located position among the wells. Individual production flowlines would then be run from the individual wells to extend to the centralized production facility where the production fluid would be gathered, separated and metered prior to transporting it to shore by means of tankers or through a pipeline.

While installation of the above-described types were satisfactory for oil fields located in shallow water, the same types of installations are impossible to construct or may be constructed only at excessive cost for deep water fields. This is especially true where the oil and gas production fluid is coming from underwater wells, that is, wells wherein the wellhead facilities are positioned underwater or close to the ocean floor. One form of a production facility adapted to be used for a deep water oil field is in the form of a vessel floating on the surface of the ocean while being relatively fixedly anchored in one position relative to the producing wells to which it is connected. Another form of oil-gathering and storage installation for handling a plurality of deep-water wells comprises a buoyant structure anchored below the ocean surface, say at a depth of from 60 to 100 feet, being held at this point by means of anchor lines so that it is outside the zone of greatest Wave action.

In the event that one of the above-described types of oil gathering installations or vessels should move off of location, it would probably cause the rupture of one or more production flowlines extending between the vessel and the underwater wells. Many of the presently known types of anchors are unsuitable for anchoring the above-described oil-gathering vessels in that they are subject to being dragged along the ocean floor during heavy storms, It is therefore a primary object of the present invention to provide an ocean floor anchor adapted to be secured to the end of an anchor line and to the ocean floor in a manner such that there is no possibility of the anchor moving from its installed position.

A further object of the present invention is to provide an ocean-floor anchor fixedly secured to the ocean floor while at the same time being readily disconnectible from the end of an anchor line so that in the event that the 3,330,338 Patented July 11, 1967 ice anchor line becomes worn, the anchor line between the anchor and the vessel can be replaced.

Another object of the present invention is to provide a method of installing and fixedly positioning in the ocean floor an anchor in a manner such that the operation can be carried out at deep water locations without the aid of a diver.

A still further object of the present invention is to provide a method and apparatus whereby an anchor line may be disconnected from an anchor on the ocean floor and replaced by remotely-operated equipment without the use of a diver.

These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

FIGURE 1 is a diagrammatic view taken in partial longitudinal section of one form of an anchoring device in accordance with the present invention;

FIGURES 2, 3, 4, 5 and 6 are schematic views taken in partial longitudinal section illustrating the sequential steps of drilling a hole in the ocean floor, stripping an anchor post and a running string down over the drill string, lowering the anchor post in the hole drilled in the ocean floor, cementing the anchor post in the ocean floor, and subsequently installing replaceable connector means at the top of the anchor post while at the same time lowering the anchor line into place while it is attached to the connector.

Referring to FIGURE 1 of the drawing, an anchor post 11 is illustrated as being positioned in a well or hole 12 drilled or formed in the ocean floor 13 in any suitable manner well known to the art. The anchor post 11 is preferably fixedly secured in the well 12 by means of cement 14. Cement 15 may also fill the major portion of the anchor post 11. In order to form the cement 14 around the anchor post 11, it is essential that the anchor post 11 be in the form of a tubular pipe or casing section having openings at both ends.

A connector housing 16 is shown as being positioned at the top of the anchor post 11. The connector housing 16 is adapted to fit in sliding axial engagement on the outside of the anchor post and therefore is provided with an upwardly-extending bore 17 therein of an internal diameter sufficient to receive the anchor post 11 therein. As shown in FIGURE 1, the connector housing 16 is preferably in the form of a tubular sleeve which may be of reinforced construction, as one having a pair of

concentric wall elements

18 and 19 arranged in spaced relationship with cement filling the space 20 between the wall elements, if desired. The connector housing 16 is provided with an inwardly-extending seating shoulder 21 in the bore 22 thereof which is adapted to seat on top 23 of the anchor post 11, or on a landing surface formed thereon. Alternatively, instead of the connector housing 16 seating on top of the anchor pile or post 11, the anchor post 11 may be provided with an outwardly extending flange 24 fixedly secured to the outer surface of the anchor post 11, as by welding, at a point below the top of the post, Thus, the

connector housing 16 would be arranged with its lower edge seated on the top of the flange 24 thereby eliminating the necessity of providing a seating shoulder 21 in the bore of the connector housing. The purpose of the seating shoulder 21 on the connector housing, or the landing flange 24 on the anchor post is to provide accurate alignment, as needed, so that a coupling member carried by the connector housing 16 is brought into accurate register at a designated position on the outer surface of the anchor post 11. The connector housing 16 is provided with suitable coupling means including elements extending inwardly into the bore of the connector housing a distance sufficient to engage the anchor post 11 so as to fixedly secure the connector housing 16 to the anchor post 11. In the one form of coupling means illustrated, the coupling means comprises substantially horizontally-extending locking screws passing through the wall 26 of the connector housing and into the bore thereof so as to engage the outer surface of the anchor post 11, or an annular groove 27 formed in the outer surface thereof. It is necessary that the head of the screws 25 extend outwardly at all times from the outer surface of the connector housing so as to be engaged by a wrench.

The connector housing 16 of the resent invention is provided with suitable landing surface means carried outwardly on the housing for receiving thereon an underwater manipulator. In the arrangement illustrated, the landing surface comprises an outwardly-extending ring element 30 adapted to seat or land a remotely-actuatable underwater manipulator device 31 thereon. Extending outwardly from the connector housing 16 are one or more pad eyes 32 or other suitable means for connecting an anchor line 33 to the pad eye. In this case a bolt 34 is employed to make this connection.

The manipulator device, generally represented by numeral 31, may be of any suitable type, one of which is shown in US. Patent 3,099,316. The manipulator device comprises a body member 36 having means such as wheels 37 for securing it to the anchor post 11, or the connector housing 16 thereof. In the embodiment illustrated, the wheels 37 are positioned on the ring element or track 30 so that the manipulator is mounted in fixed relationship to the anchor post 11. Instead of employing Wheels on the track 30 it is to be understood that the track 30 could be omitted with the manipulator device being secured to the anchor post 11 or its connector housing 16 by any other suitable connector means such as clamping arms, suction cups, electromagnets, etc. Since the connector means carried by the manipulator do not form part of the present invention, they will not be described in greater detail here. The wheels 37 are pref erably actuated by motor means operatively connected to the wheels and positioned inside or outside the body member 36. Additionally, the body member 36 is preferably provided with a pair of idler rollers 38 mounted on an outwardly-extending frame 39 to contact the outer surface of the connector housing 16, as shown in FIG- URE 1 where the drive wheels 37' are positioned on the track 30. Alternatively, the rollers 38 could be poweractuated and friction contact with the outer surface of the connector housing 16 to drive the manipulator device 31 around the anchor post 11.

A portion of the body member 36 is arranged for upward extension therefrom, preferably in the form of a telescoping arm 40. Mounted on the top of the telescoping arm or body portion 40 in a laterally-extending cylinder 41 having a telescoping arm 42 extendible outwardly therefrom. The arm 42 is provided with a rotatable wrench head 43 that is power operated by suitable motor means mounted in the arm 42 by the cylinder 41, preferably in the rear portion 44 thereof. A television camera 45 and suitable lights 46 are mounted at the top of the manipulator device -on.a power-actuated light swivel and tilting mechanism 47, while the television viewing screen is positioned on a vessel 48 (FIGURE 2) at the surface.

The manipulator device 31 may be suspended on a hook 50 having a weight-supporting and current-transmitting cable 51 attached to its upper end. Thus, power for operating the manipulator device and its associated equipment is sent down the cable 51 from the vessel 48 While television signals are returned up the cable to the vessel. At the same time, the manipulator device 31 may be lowered from the vessel 11 by means of the cable 51 and its associated hoist (not shown) to any selected level in the water. For moving the manipulator device 31 laterally at the end of the cable 51, the manipulator device is provided with suitable propulsion means such, for example, as motor-driven propellers 52 which are mounted outboard of the body member 36 on at least two sides thereof. At least a portion of the body member 26 may form a void chamber which maybe selectively flooded by'controls of the vessel 48 for adjusting the buoyancy of the manipulator device 31. If additional buoyancy is desired, suitable buoyancy tanks may be secured to the weight supporting cable 51.

One method of sinking the anchor of the present invention is illustrated in FIGURES 2 through 6. Anchor installing operations may be carried out from any suitable vessel, barge or platform such as the one schematically represented by numeral 48 in FIGURES 2 through 6. The barge is provided with a suitable derrick -54 equipped with conventional fall lines 55 of a hoist system adapted to raise and lower a drill string or other pipe string 56. In the event that the anchor post 11 (FIGURE 1) is to be drilled into the ocean floor, the barge 48 (FIGURE 2) is provided with a suitable rotary table 57. It is to be understood that the anchor post of the present invention may be driven into the ocean floor by means of an underwater pile driver or a pile driver operating on the vessel 48 with a driving connection such as a'string of pipe extending from the top of the anchor post to the pile driver (not shown) on the vessel. Alternatively, a string of pipe may be lowered from the vessel to the ocean floor and water pumped down the pipe string and jetted into the ocean fioor as the pipe string is being lowered, thereby forming a hole in the ocean floor into which the anchor post 11 may be inserted. In this operation, it is preferred that the anchor post 11 would form the lower end of the jetting pipe string and be disconnectible therefrom. Thus, after jetting the anchor post 11 in the ocean floor, cement could be pumped down the pipe string, around the bottom of the anchor post and up the side thereof, with the pipe string extending from the top of the anchor post of the.

vessel being subsequently disconnected from the anchor post and pulled back to the vessel.

Preferably, however, the pipe string 56 (FIGURE 2) is provided with a drill bit 58 at the bottom thereof and a collapsible expander bit 59 positioned thereabove. An anchor post hole 60 is then formed in the ocean floor 13 by rotating the drill string 56 at the vessel 48. When the hole 60 has been drilled to its desired depth, a running a pipe string 61 (FIGURE 3) having an anchor post 11' secured to the bottom thereof is lowered down over the drill string 56. While the anchor post 11 (FIGURE 4) may be cemented in place by pumping cement down the drill string 56 and .out the bit 58 thereof, with the drill string 56 being later employed to guide the connector housing 16 into place, as shown in FIGURE 6 it is preferred that the .drill string and bit be pulled back to the vessel after at least the lower end of the anchor post 11 has entered the-hole 60 in the ocean floor 13.

When the anchor post 11 has been positioned at the desired depth in the hole 60, a cementing pipe string 62 of a smaller diameter is run down through the running pipe 61 (FIGURE 4) and the running string 61 may then be stripped up to the vessel again. As illustrated in FIG- URE 5, the upper end of the cementing pipe string 62 is connected by a conduit 63 to a cement pump and source of cement 64. The cement passes down the cementing pipe string'62 and through the anchor post 11, around the bottom thereof and thence upwardly to fill the annular space 65 between the outside of the anchor post 11 and the wall of the halo 60. After the cement has hardened, the cementing pipe string 62 is used as a guide down along which a connector housing 16 and its running pipe string are lowered until the connector housing 16 is seated on the anchor post 111 in a manner described hereinabove with regard to FIGURE 1. The lower end of the running pipe string 66 may be connected to the'top of the connector housing 16 in any suitable manner, as by screw threads, J-latches, etc. In FIGURE 1 the running pipe string 66 is illustrated as having provided on its lower end a cap 67 equipped with horizontally-extending locking screws 68 which are adapted to disconnect underwater by means of the manipulator device 31 lowered and propelled through the water, as described hereinabove with regard to locking screws 25 at the top of the closure housing 16.

As illustrated in FIGURE 6, the anchor line 33 is preferably secured to the connected housing 16 before lowering it into place on the anchor post 11. However, it is to be understood that the anchor line could be subsequently connected to the connector housing 16 by means of a manipulator device 31. If desired, the manipulator device 31 may be mounted on the ring element or track 30 surrounding the connector housing 16 before it is lowered into place from the vessel down to the anchor post 1 1 at the ocean floor. Alternatively, the connector housing 16 may be lowered as illustrated in FIGURE 6 into place on the anchor post 11, with the manipulator device being later lowered through the water down to the connector housing where it would be positioned thereon. As may be seen from FIGURE 1, the telescoping arm 40 of the manipulator device 31 may the raised or lowered to bring the Wrench head 43 of the telescoping arm 42 into register with the locking screws 25 so as to run the screws 25 into place and connect the connector housing 16 to the anchor post 11. Operations are carried out by observing the screws and manipulator wrench head 43 by means of a television camera 45 which may also be employed to locate the anchor post in the first place. After one screw 25 has been run into place, the drive wheels 37 of the manipulator device 31 are energized so that the manipulator device is moved about the track 30 until its Wrench head 43 is positioned opposite another screw. This operation is repeated until all the screws have been connected. Subsequently, the telescoping arm 40 would be extended to raise the wrench head 43 opposite the screws 68 which connect the bottom of the running string 66 to the connector housing 16. After the screws were disconnected, the running pipe string 66 would be pulled back to the vessel. The other end of the anchor line at the vessel would then be moved and connected to the structure being anchored in the ocean. The manipulator device 31 at the end of its operations would be lifted off the track 30 and pulled back to the vessel 48.

I claim as my invention: 1. An anchor adapted to secure anchor lines to the ocean floor, said anchor comprising an anchor post sunk in the ocean floor, connector housing ada ted to fit in sliding axial engagement on the outside of said anchor post, said connector housing having a bore therein extending upwardly from the bottom thereof, said bore being of a size to receive said anchor post therein,

coupling means carried by said connector housing, said coupling means including rigid mechanical connector means extending inwardly into the bore of said connector housing and engageable with said anchor post therein, and

an anchor line connector carried outwardly on said connector housing for securing the end of an anchor line thereto, and a substantially laterally extending anchor line extending therefrom.

2. The apparatus of claim 1 including landing surface means carried outwardly by said connector housing for receiving an underwater manipulator thereon.

3. The apparatus of claim 2 wherein said securing means of said coupling means comprises substantially horizontally extending locking screws, the heads of said screws extending outwardly at all times from the outer surface of said connector housing.

4. The apparatus of claim 2 including cement surrounding the anchor post in the ocean floor.

5. The apparatus of claim 2 including an inwardlyextending seating shoulder in the upper end of the bore of said connector housing of a size adapted to engage the upper end of said anchor post.

6. The apparatus of claim 2 wherein said connector housing is a tubular sleeve.

7. The apparatus of claim 6 wherein said landing surface means is an outwardly-extending ring element secured to the outer surface of said connector housing.

8. The apparatus of claim 7 wherein said landing surface ring element is arranged in spaced relationship to said connector housing outer surface.

9. The apparatus of claim 7 wherein the tubular sleeve of said connector housing includes inner and outer con centric wall elements in spaced relationship with each other.

10. The apparatus of claim 9 including cement filling the space between the inner and outer wall elements.

11. A method of setting an anchor line in the ocean floor, said method comprising the steps of sinking an anchor post into the ocean floor so that the top of the anchor post is near the ocean floor, maintaining contact between the top of the anchor post and a vessel thereabove on the surface of the ocean, connecting a laterally extending anchor line to a connector housing, lowering the connector housing and the end of the anchor line connected thereto from the vessel onto the anchor post sunk in the ocean floor, and

connecting the upper end of the connector housing to said anchor post so that the anchor line extends substantially laterally therefrom.

12. The method of claim 11 including the step of positioning an underwater manipulator adjacent said connector housing for connecting the connector housing to said anchor post.

13. The method of claim 12 including the step of positioning said underwater manipulator on said connector housing prior to lowering said connector housing through the water from said vessel.

14. The method of claim 12 including the step of positioning said underwater manipulator on said connector housing after positioning said connector housing on said anchor post.

15. The method of claim 11 including the step of forming a hole in the ocean floor prior to sinking the anchor post therein.

16. The method of claim 15 including the step of cementing the anchor post in the hole formed in the ocean floor.

17. The method of claim 15 wherein said hole is formed by a drill string and including the step of sliding the anchor post and a running pipe string down the drill string and into the hole.

References Cited UNITED STATES PATENTS 390,319 10/1888 Thompson 6l48 2,236,682 4/1941 Gross 6146.5 2,583,965 1/1952 Page et al -6 2,693,255 11/1954- Dicke et al 52-148 X 2,891,770 6/1959 Bauer et al. 175-7 2,961,838 11/1960 Vander Wilt 61-48 3,001,617 9/1961 Clevett 52148 X 3,020,956 2/1962 Suderow 1755 X FOREIGN PATENTS 849,724 9/ 1960 Great Britain.

CHARLES E. OCONNELL, Primary Examiner. R. E. FAVREAU, Assistant Examiner.

Claims

1. AN ANCHOR ADAPTED TO SECURE ANCHOR LINES TO THE OCEAN FLOOR, SAID ANCHOR COMPRISING AN ANCHOR POST SUNK IN THE OCEAN FLOOR, CONNECTOR HOUSING ADAPTED TO FIT IN SLIDING AXIAL ENGAGEMENT ON THE OUTSIDE OF SAID ANCHOR POST, SAID CONNECTOR HOUSING HAVING A BORE THEREIN EXTENDING UPWARDLY FROM THE BOTTOM THEREOF, SAID BORE BEING OF A SIZE TO RECEIVE SAID ANCHOR POST THEREIN, COUPLING MEANS CARRIED BY SAID CONNECTOR HOUSING, SAID COUPLING MEANS INCLUDING RIGID MECHANICAL CONNECTOR MEANS EXTENDING INWARDLY INTO THE BORE OF SAID CONNECTOR HOUSING AND ENGAGEABLE WITH SAID ANCHOR POST THEREIN, AND AN ANCHOR LINE CONNECTOR CARRIED OUTWARDLY ON SAID CONNECTOR HOUSING FOR SECURING THE END OF AN ANCHOR LINE THERETO, AND A SUBSTANTIALLY LATERALLY EXTENDING ANCHOR LINE EXTENDNG THEREFROM.