US3347053A - Partially salvageable jacket-pile connection - Google Patents

Description

Oct. 17, 1967 w. F. MANNING 3,347,053 PARTIALLY SALVAGEABLE JACKET-FILE CONNECTION Filed April 28, 1965 4 Sheets-Sheet l WILLIAM E MANNING C219, PM

Oct. 17, 1967 W. F. MANNING Filed April 28, 1965 4 Sheets-Sheet 2.

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lA/l/E/VTQR WILLIAM E MANNING 5) ATTORNEY.

Oct. 17, 1967 w. F. MANNING 3,347,053

PARTIALLY SALVAGEABLE JACKET PILE CONNECTION Filed April 28, 1965 4 Sheets-Sheet 3 WILLIAM F MANNING ATTORNEY W. F. MANNING 3,347,053 PARTIALLY SALVAGEABLEY JACKET-FILE CONNECTIO Filed April 28, 1965 50 4 Sheets-Sheet 4 as K i 24 m/vs/vrom WILLIAM F MANNING Claw/ M A TTOR/VEX United States Patent 3,347,053 PARTIALLY SALVAGEABLE JACKET-PILE CONNECTION William F. Manning, Springdale, Conn., assignor to Mobil Oil Corporation, a corporation of New York Filed Apr. 28, 1965, Ser. No. 451,428 19 Claims. (Cl. 6146.5)

ABSTRACT OF THE DISCLOSURE This specification discloses a subsea connection for mooring an offshore facility comprising a tubular jacket as a first connecting element, which is permanently fixed to the offshore facility, a coaxial intermediate casing asa second connecting element releasably coupled at the upper ends thereof, as by bolts, to the first connecting element. A chamber is formed between the second connecting element and a pile as a mooring element for injecting grout or cement thereinto to form a permanent connection between the pile and the second connecting element. The jacket is generally cylindrical in shape and fits coaxially around the pipe. The intermediate casing also generally cylindrical, may be designed to be inserted within the pile, if the pile be hollow, or between the pile and the jacket. By unbolting the first and second connecting elements, the offshore facility can be removed without damage.

This invention relates to an improved mooring for marine structures; or more specifically, to a mooring device for an offshore facility servicing a submerged well, the offshore Well servicing facility being fixed to the bottom of a body of Water by the mooring device, for a time, after which the facility is moved as expeditiously as possible to another location and again rigidly moored.

In coastal or offshore waters, the oil produced from submerged wells is either piped directly along the bottom to onshore intsallations, or the production is controlled from a platform adjacent the well site and the oil stored in the water, preferably adjacent the submerged Well. Where the well is several miles offshore, pipelines from the well to the shore become prohibitively expensive, as well as impractical, and the control of the Well and the storage of the accumulated oil is better accomplished at the well site for the production of the oil to be economically feasible. Servicing facilities for such a submerged oil well must be capable of being rigidly moored at the site so as to withstand the punishment inflicted by waves, as Well as that of violent storms. The facility must also be capable of being moved to another well site without a long repair time being required. Servicing facilities, such as a production platform or a submerged storage device, must be capable of being rigidly moored at the well site and later being shifted to another well site without damaging the facility in the move.

A common method of mooring offshire facilities is by means of piles, each driven down through a tubular portion or hollow jacket, permanently fixed to the servicing facility, into the sea bottom. In the prior art, particularly when the jacket-pile connection is underwater, the upper end of the pile is then usually rigidly connected to the tubular portion or hollow jacket by a settable adhesive such as grout or cement. While this procedure does provide a rigid connection, the hardened adhesive permanently fixes the pile to the jacket so that in breaking the connection, to move the offshore well servicing facility, the jacket is invariably damaged. While it is immaterial that the pile is destroyed, when the jacket-pile connection is broken, the damaging of a portion of the servicing facility itself can cost a well operator many thousands of dollars in lost time. A partially salvageable jacket-pile connection for coupling a mooring pile rigidly to an integral portion of a submerged-well servicing facility, which would permit salvage of the part of jacket-pile connection permanently fixed to the servicing facility, would provide the necessary mobility required to obtain efficient operation.

One common prior art method of connecting the pile to the jacket, so as to permit the connection to be broken when the servicing facility is to be moved, is by welding the pile directly to the jacket, particularly when the jacket-pile connection is above the surface of the body of water. The pile is welded to the inside of the jacket and then the weld is broken when the servicing facility is to be moved. Although this procedure has been used successfully at times, it does have its drawbacks, particularly for use underwater. If theweld is made strong enough to insure against the pile breaking free of the jacket, the weldmay be so strong that the jacket may be damaged when the connection is broken. An equally imptorant problem arises most frequently in very large structures where the jacket and the pile would have thick walls. It is difficult to obtain a high enough welding temperature due to heat dissipation in the water, to obtain a good weld or to later break the connection underwater. It has been found from long experience that the integrity of underwater welds is always questionable. Furthermore, if the point at which the weld must be made is quite a distance under the surface, the time that a diver would be able to stay down at that point would be quite restricted and the connection would be even more suspect.

It is an object of the present invention to provide a method for rigidly mooring a marine servicing facility at a submerged well site while providing for the relocating of the facility without the necessity of permanently damaging or disabling any integral portion thereof.

It is a further object of the invention to provide a means for rigidly mooring a submerged storage facility comprising a partially salvageable jacket-pile connection, which may be released or disengaged without affecting the physical integrity of the storage facility.

It is another object of the invention to provide a means for rigidly mooring a marine production platform which may be disengaged without affecting the physical integrity of the platform.

It is a more specific object of the invention to provide a means for connecting anchoring piles to a submerged storage facility by a settable liquified adhesive in such a manner that the piles can be easily removed and in expensively disposed of, without damaging any integral components of the storage facility.

These and still further objects of the invention will be evident from a reading of the following description taken in conjunction with the accompanying drawings.

In accordance with the invention, an intermediate casing is releasably coupled within a jacket rigidly fixed to aservicing facility for receiving the upper end of a pile, whereby the pile may be connected by a grouting process to the releasable intermediate casing rather than directly to the jacket forming a portion of the facility itself.

In accordance with an embodiment of the invention a number of hollow cylindrical tubes or jackets are fixed to a marine facility located at an offshore submerged well site. To moor the facility, with respect to the bottom of the body of water, a hollow pile is extended down through each jacket and driven into the earth below, after which the top end of the pile is cut off approximately at the top of the jacket. After the pile has been driven down the required distance and cut off, an intermediate casing, having an annular seal encircling the lower end thereof, is inserted down through the upper end of the pile. The intermediate casing is bolted, by a'diver, to a flange formed '1 C) at the upper end of the surrounding jacket. An adhesive is then injected through a central pipe into the annular area defined by the periphery of the intermediate casing and the circumferential inner wall of the hollow pile in conjunction with the sealing means at the lower end of the casing. When the adhesive has hardened, the pile becomes permanently fixed to the intermediate casing. The intermediate casing, in turn, is bolted tightly to a flange at the top of the jacket, by the spider, forming a rigid mooring structure.

In accordance with another embodiment of the invention, a hollow intermediate casing, having an annular seal fixed to the interior wall, at the lower end thereof, isv

first inserted within the jacket and is fixed thereto by means of a series of bolts extending through abutting upper flanges on each. A hollow pile is then driven downwardly into the bottom of the body of water through guide means in the intermediate casing and the jacket. An adhesive is injected into the annular space defined by the inside wallof the intermediate casing and the outside wall of the hollow pile, in conjunction with the sealing means in the lower end of the intermediate casing.

In accordance with another embodiment of the invention, the hollow pile is first driven down through the jacket and the intermediate casing is inserted therethrough as in the first discussed embodiment. However, in this instance the structure for connecting the intermediate casing to the outer jacket is of such a configuration that the jacket may be drawn up over the pile to remove it therefrom without cutting the pile off below the jacket as previously discussed.

In the drawings:

FIGURE 1 is a slide elevational view of an oil storage facility, which having been floated to the site of a submerged .well, is in the process of being filled with water to sink the storage facility to the bottom where it can be moored;

FIGURE 2 is a side elevational view of the oil storage facility, of FIGURE 1, already moored by piles driven into the bottom, through vertical jackets aflixed to the storage facility, each of the piles being releasably coupled to its respective jacket at a point relatively close to the surface;

FIGURE 3 is a diagrammatic elevational view of an offshore floating production platform with a rig thereon, rigidly moored to the bottom of a body of water, by means of piles connected to the platform structure under the surface of the water in accordance with the instant invention;

FIGURE 4 is a side elevational view, in section, of a first embodiment of the partially salvageable jacket-pile connection wherein the intermediate casing has been inserted within the pile;

FIGURE 5 is a side elevational view, in section, showing a second embodiment of the partially salvageable jacket-pile connection wherein the pile has been centered within the intermediate casing; and

FIGURE 6 is a side elevational view, in section, of a partially salvageable jacket-pile connection similar to that of FIGURE 4 in which the jacket may be lifted up over the pile without prior cutting of the pile from its mooring.

Referring specifically to FIGURE 1, a submergeable oil storage facility, generally designated 10, is illustrated as being ballasted from a first position in which the storage facility 10 floats on the surface 18 of the body of water toward a second position in which it rests on the bottom 20 of the body of water. The storage facility 10 consists of a lower storage tank 12 and a number of upwardly.

extending hollow cylindrical tubes or jackets 14 held in place on the storage tank 12 by means of braces 16 extending between the tank 12 and the jacket 14 as well as between the individual jackets 14. The storage facility 10 is floated 'by filling the storage tank 12 with air and then the facility 10 is towed by a. tug (not shown) to a site ad- 4 jacent the submerged well site where the tank 12 is filled with water to sink it.

As shown in FIGURE 2 the storage facility 10tis finally broughtto rest with the storage tank 12 supported by the bottom 20, which is shown as being 250 feet below the surface 20, and is moored, or held in place, by mooring elements comprising hollow metal pipes referred to in the art as piles, one driven down through each of the jackets 14 into the earth below. A pile 22 is inserted into each jacket 14 from the surface. 18 and then is driven into the bottom 20 by a pile driver mounted on a barge (not shown). After the piles 22 eachhave been driven a requisite distance into the bottom 20, the portion of each pile 22 extending above the top of its jacket 14 is cut elf. The upper end of each pile 22 is then rigidly fixed within its associated jacket 14 by the partially salvageable jacketpile connection of the invention, generally designated 24. As shown, the storage tank .12 lies on the bottom 20 with the jackets 14 extending to within feet of the surface 18 so that the partially salvageable jacket-pile connection 24 may be easily worked on by a diver. The storage tank 12 can now be filled with oil while remaining on the bottom 20, although the oil will cause the tank to be buoyant.

Referring to FIGURE 3, a servicing facility taking the form of a working or production platform, generally designated 26, with a rig 28 extending from a deck 30 thereon, is rigidly moored beneath the surface 18 of the body of water by a number of hollow vertical piles 22 embedded in the bottom 20 of the body of water. The upper end of each of the piles 22 is encased within a hollow cylindrical jacket 14' which is, in turn, welded ,or riveted 'beneath the platform deck 30 by means of a network of braces 32 to constrain the platform 26 against movement with respect to the piles 22. The jackets 14 are fixed in relation to the platform so as to be completely submerged when the platform is afloat. Each pile 22 is held rigidly, but removably, within its respective jacket 14' by the par. tially salvageable jacket-pile connection 24, which is also submerged. The platform 26, as shown, also has a number of buoyant tanks 34 for floating the platform 26 to the site at which it is to be moored.

The embodiments of the partially salvageable jacket-- pile connection 24 willbe discussed in conjunction with the submerged storage facility 10 of FIGURES 1 and 2 with which it can be most advantageously used. Although the connection 24 is also shown in conjunction with an above surface platform 26 (FIGURE 3) the invention is most useful where no portion of the structure of the servicing facility is above the surface of the water.

As previously discussed, a pile 22 is driven down through each vertical jacket 14, serving as a first connecting element of the partially salvageable jacket-pile connection as the storage facility 10 rests on the bottom. As shown in FIGURE 4, the pile 22 is coaxially located within a socket 23 formed by the hollow interior of the jacket. 14 by centering means 36'and an intermediate casing 38, a second connecting element of the partially salvageable jacket-pile connection, has been inserted into the hollow pile 22 and nests therein. A spider or bridging means 40, consisting of a number of downwardly diverging arms 42, is welded prior to installation, at its upper end to the upper end of the casing 38. A separate horizontal foot 47 on the lower end of each of the arms 42 is releasably coupled to an annular flange or disc-shaped element 44, encircling and rigidly coupled to the upper end of the jacket 14, by means of bolts 46 extending therethrough. For additional strength, an annular ring can be substituted for the feet 47. A resilient, outwardly extending annular seal 48,cemented to the lower end of the intermediate casing 38, coacts with the inner periphery of the pile 22 to seal the annular space defined by the lower end of the casing 38 and the adjacent inner wall of the hollow pile 22. A cement injection tube 50 may be extended down into the hollow intermediate casing 38 so that cement can be forced through a small hole 52 in the wall thereof :into

the annular space between the casing 38 and the pile 22 to fill the space therebetween. When the cement hardens, it holds the casing 38 rigid relative to the pile 22.

When it is desirable to move the submerged storage facility to another location, a diver need only go down 100 feet beneath the surface 18, to the partially salvageable jacket-pile connection 24 to remove the bolts 46 cou pling each of the intermediate casings 38 to their respective piles 22. Each of the piles 22 is then severed below the bottom 20. This may be done by a prior art mechanical cutter lowered down into the pile 22, or if the pile 22 has a large enough diameter, by a man, while the inside of the pile 22 is kept free of water by air pressure. An explosive charge detonated within the pile 22, beneath the bottom 20, may also be used. The intermediate casings 38 and the upper sections of the piles 22 are then pulled up out of the jackets 14, before the storage facility is refloated, resulting in the jackets 14 being unharmed and ready for mooring the storage facility in another location. During the entire operation no diver is required to go deeper than 100 feet beneath the surface 18 although the storage facility 10 is on the bottom 20, 250 feet beneath the surface 18.

FIGURE 5 shows a second embodiment of the invention wherein an intermediate casing 38 is inserted directly into the cylindrical jacket 14, held coaxially therewith by centering means 54, and fixed rigidly thereto by means of a number of bolts 46 extending through a pair of annular planar flanges 56, 58, welded to the upper ends of the intermediate casing 38 and the jacket 14, respectively, and abutting each other. The hollow pile 22 is now driven down through a central passage 60 in the intermediate casing 38 and nests therein while being held coaxially with respect to the jacket 14 by centering means 62 in the intermediate casing 38' and centering means 54 below the intermediate casing 38' in the jacket 14. The pile 22 also coacts with a sealing means 64, mounted within the lower end of the intermediate casing 38', to provide an annular space that may be filled with cement through an injection tube 50, extending down into the pile 22, and through a hole 66 in the wall thereof, into the composite annular space. When the storage facility 10 is to be moved and the piles 22 are cut, the intermediate casings 38 are unbolted from the jackets 14, and then the permanently attached intermediate casings 38' and piles 22 may be pulled out of the jackets 14 as in the embodiment of FIGURE 4.

FIGURE 6 shows another embodiment of the invention in which there is an intermediate casing 38" which extends down within the hollow pile 22. As in FIGURE 4, the pile 22 is again held temporarily coaxial with relation to the outer jacket 14 by means of a centering means 36 before the annulus between the pile 22 and the intermediate casing 38" is filled with cement and the cement hardens. As in the earlier embodiments, a radial annular flange 44 is fixed to the upper end of the jacket 14. An annular flange or disc-shaped element 68 is also rigidly fixed to the upper end of the intermediate casing 38", extending above the pile 22 and jacket 14. The outer diameter of the flange 68 on the casing 38" is smaller than the inside diameter of the jacket 14 so that the jacket 14 with the connected platform 26 (as later described) may be raised over the permanently connected pile 22 and intermediate casing 38" without interference. The intermediate casing 38" is connected to the jacket 14 by means of a spider 49' composed of a number of individual arms 70 each having separate horizontal feet at the ends thereof and which are each coupled by bolts 72 extending through the upper feet 71 and the flange 68 on the intermediate casing 38" and diverge downwardly to a point at which they are coupled by bolts 46 extending through the lower feet 71 and to the circumferential flange 44 on the upper end of the jacket 14. By unbolting and removing all of the arms 70 at both their upper and lower ends, the jacket 14 is disconnected from the casing 38 and may be lifted up and off the cementconnected pile 22 and intermediate casing 38" by filling 6 the storage tank 12 (FIGURE 2) with oil or air to float the facility up off the piles 22. After the storage facility 10 is towed away, the piles 22 may be severed as discussed previously.

It may not be obvious to the reader why a bolt-on coupling is not made directly from each of the piles 22 to its associated jacket 14. Particularly in an embodiment such as illustrated in FIGURE 5, it might appear, to one not familiar with the problems in this field, that a flange, such as flange 56, on the intermediate casing 38', could be welded directly to the upper end of the pile 22. Such an innovation would appear to obviate the need for any intermediate casing 38' and the grouting step. This type of installation, while simpler in structure, is not feasible because of several factors: (1) the hammering forces used to drive the pile 22 into the bottom 20 could easily break the flange 56 if it were connected directly to the pile 22; (2) it is diflicult to drive a pile 22 into the jacket 14 the exact distance necessary to permit the flanges 56 and 44 to abut; and (3) it is diflicult to keep the piles 22 from turning during installation and therefore the bolt holes in the flanges 44, 56 could not be aligned properly.

The embodiment of FIGURE 5 has an added advantage, over those of FIGURES 4 and 6, that the annular flanges 56 and 58 can be coupled together by the bolts 46 prior to the submergence of the offshore well servicing facility to which the jacket 14 is fixedly connected. After the offshore facility is submerged at a site, a pile 22 is driven through each of the jackets 14. Cement is then injected into the annulus between the .pile 22 and the intermediate casing 38 to form an adhesive connection. All this is done without any need for a diver. When it is desirable to remove the offshore well servicing facility from the site, the piles 22 are cut beneath the permanent adhesive connection between the intermediate casing 38' and the pile 22. After the offshore well servicing facility is brought to the surface, the bolts 46 are removed and the jackets 14 and the intermediate casings 38' are un coupled. All that remains to be donetis for each of the intermediate casings 3-8 and the attached upper sections of piles 22, permanently connected thereto, to be lifted out of the jackets 14. When the offshore well servicing facility is to be again moored at a submerged site, a new intermediate casing 38' is coupled to each jacket 14 by bolts 46 prior to the offshore well servicing'facility being submerged.

While the specific embodiments of the partially salvageable jacket-pile connection 24 have all been described in conjunction with the completely submerged storage facility 10 of FIGURES l and 2, the inventive connection 24 would be useful in any submerged connection such as that designed to moor the floating platform 26 of FIGURE 3. In instances where it is necessary to keep the total cross sectional area of the platform 26, at surface 18 of the body of water, small, and the piles 22 are necessarily large diameter pipes because they are required to extend a great distance before reaching the bottom 20 (400-600 feet), the connection between the platform 26 and the piles 22 is best made at a distance beneath the surface where the effects of surface conditions will not be severely felt feet). Relatively small diameter support legs of the platform can be fixed to the relatively large diameter piles by means of the jackets 14' beneath the surface. The partially salvageable jacket-pile connection 24 may also be used in instances where the top of the pile 22 extends above surface 18 of the body of water although with no particular advantage over prior art methods.

Certain modifications of the preferred form of the invention have been described and it is apparent that other modifications may be made without departing from the invention as defined in the fol-lowing claims.

Having described the invention, what is claimed is:

1. A partially salvageable mooring means, for connecting an offshore well servicing facility beneath the surfaceof a body of water to a mooring element, fixedly posi tioned in the body of water, comprising: a first connecting element-of said mooring means adapted to be permanently fixed to the offshore well servicing facility to be fixedly positioned in a body of water, a second connecting element of said mooring means adapted to be permanently fixed, by an adhesive material, to the mooring element fixedly positioned in the body of water, means for in: jecting an adhesive material between said second connecting element and the mooring element for permanently fixing said second connecting element to the mooring element fixedly positioned in a body of water, and nondestructive releasable fastener means for coupling and recoupling said first and second connecting elements together at the same point along the length of the fixedly positioned mooring element and said second connecting element beneath a body of water whereby said first connecting element is permanently fixed to the offshore well servicing facility and said first and second connecting elements are releasably coupled together prior to being positioned beneath the surface of a body of water with the offshore well servicing facility, said first connecting element being fully salvageable with the offshore well servicing facility to which it is permanently fixed by the nondestructive uncoupling of said first and second connecting means when the offshore facility is to be removed.

2. A partially salvageable mooring means, for connecting an offshore well servicing facility beneath the surface of a body of water to a mooring element, fixedly positioned in the body of water, comprising: a first connecting element of said mooring means adapted to be permanently fixed to the offshore well servicing facility to be fixedly positioned in a body of water, a second connecting element of said mooring means adapted to be permanently fixed to the mooring element fixedly positioned in the body of water, means for permanently fixing said second connecting element to the mooring element fixedly positioned in the body of water including a portion of a chamber formed in said second connecting element, said portion of a chamber being adapted to coact with the mooring element when said second connecting element is in an operative relationship therewith, beneath the surface of a body of water, to form a chamber to retain a substantially fluid cement, means for injecting a substantially'fluid cement into said chamber, and a means for nondestructively releasably coupling and uncoupling said first and second connecting elements together beneath a body of water whereby said first connecting element is fully salvageable with an offshore well servicing facility to which it is adapted to be permanently fixed when the offshore well servicing facility is to be removed and the connection between the offshore well servicing facility and the mooring element fixedly positioned in a body of water must be broken.

3. The partially salvageable mooring means of claim 2 wherein said mooring element is a fully submerged pile having the lower end thereof embedded in the earth beneath the surface of a body of water.

4. In the partially salvageable mooring means of claim 3, a socket extending through said first connecting element, said pile and said second connecting element ex-v tending through said socket when operatively connected to moor, the offshore well servicing facility.

5. In the partially salvageable mooring means of claim 4, said first connecting element being cylindrical in shape with said, socket being a concentric passage extending therethrough.

6. -In the partially salvageablemooring means of claim 5, a central passage extending through thelength of said pile and said second connecting element nesting in said central passage when there is an operative connection between the pile and the first connecting element.

7. In the partially salvageable mooring means of claim 5, a central passage extending through the length of said second connecting element and said pile nesting in said 8 central passage when there is an operative connection between said pile and said first connecting element.

8. In the partially salvageable mooring means of claim 4, said first and second elements being substantially cyindrical and fixed in a concentric relationship when said first element is operatively connected to said mooring pile.

9. In the partially salvageable mooring means of claim 8, said pile being a hollow pipe and said second element being centrally positioned therewithin.

10. In the partially salvageable mooring means of claim 9, an outwardly extending annular seal fixed to the lower end of said second connecting element, said outer periphery of said seal being at least equal to the inner periphery of said hollow pope whereby said seal acts as the lower boundary for a space defined by the inner periphery of said pipe and the outer periphery of said second element whereby said space is adapted to contain grout to fix permanently said second connecting element to said pipe.

11. In the partially salvageable mooring means of claim 10, a flange rigidly mounted on the upper end of said first connecting element, a bridging means extending outwardly from the upper end of said second connecting element, and means for releasably connecting said flange to said bridging means whereby said pipe is rigidly connected to said second element but said second element is releasably connected to said first element.

12. In the partially salvageable mooring means of claim 11, said flange being a first disc-shaped circumferential element mounted perpendicularly to the axis of said first connecting element, and said bridging means being a series of outwardly extending arms equally spaced around said second connecting element.

13. In the partially salvageable mooring means of claim 12, means releasably fixing said arms to said sec ond connecting element.

14. In the partially salvageable mooring means of claim 13, said means for releasably locating said arms on said second connecting element comprising a second discshaped circumferential element rigidly fixed to the upper end of said second connecting element, said second flange having an outer diameter less than the inner diameter of said first connecting element.

15. In the partially salvageable mooring means of claim 8, said second connecting element being a hollow pipe and said pile being centrally positioned therewithin.

16. In the partially salvageable mooring means of claim 15, an annular seal fixed within the lower end of said second connecting element said annular seal having a central hole therethrough so proportioned that when said pile is located within the second connecting element the seal closes the space between said pile and the second connecting element whereby said seal acts as the,

lower boundary for a space defined by the inner periphery of said second connecting element and the outer pe- I riphery of said pile, said space being adapted to contain grout to fix permanently said second connecting element to said pile.

17. In the partially salvageable mooring means of claim 16, a first circumferential flange rigidly mounted on the upper end of said first connecting element, a second circumferential flange rigidly mounted on the upper end of said second connecting element, said flanges abutting when said pile is operatively connected to said first connecting element, and releasable means for coupling said first and second flanges in abuttting relation.

18. A method for mooring an offshore well servicing,

facility in a body of water, by a pile driven into the bottom of said body of water so that the portion of a moor,-

ing structure permanently fixed to said platform is sal- 1 vageable, wherein said facility has at least one tubular jacket fixed permanently thereto near the surface of said body of water and adapted to be connected operatively to said pile, comprising the following steps:

(a) driving said pile down through said jacket into said bottom of said body of water to moor said pile;

(b) cutting off the top of said pile at a point substantially equal to the top of said jacket;

(0) inserting an intermediate casing into said jacket, 5

encircling said pile and leaving an annular space between said intermediate casing and said pile;

(d) releasably coupling said jacket to said intermediate casing; and

(e) injecting grout into the annular space between said intermediate casing and said pile and holding said pile stationary with respect to said intermediate casing until said grout hardens.

19. A method for mooring an offshore Well servicing facility in abody of Water by a hollow pile driven into the bottom of said body of water so that the portion of a mooring structure permanently fixed to said platform is salva-geable, wherein said facility has at least one tubular jacket fixed permanently thereto near the surface of said body of water and adapted to be connected operatively 20 to said pile, comprising the following steps:

(a) driving said pile down through said jacket into said bottom of said body of water to moor said pile;

References Cited UNITED STATES PATENTS Day.

Upson 61-46 Samuelson 61-46.5 X Siebenhausen 6146.5

DAVID J. WILLIAMOWSKY, Primary Examiner.

JACOB SHAPIRO, Examiner.

Claims (1)

1. A PARTIALLY SALVAGEABLE MOORING MEANS, FOR CONNECTING AN OFFSHORE WELL SERVICING FACILITY BENEATH THE SURFACE OF A BODY OF WATER TO A MOORING ELEMENT, FIXEDLY POSITIONED IN THE BODY OF WATER, COMPRISING: A FIRST CONNECTING ELEMENT OF SAID MOORING MEANS ADAPTED TO BE PERMANENTLY FIXED TO THE OFFSHORE WELL SERVICING FACILITY TO BE FIXEDLY POSITIONED IN A BODY OF WATER, A SECOND CONNECTING ELEMENT OF SAID MOORING MEANS ADAPTED TO BE PERMANENTLY FIXED, BY AN ADHESIVE MATERIAL, TO THE MOORING ELEMENT FIXEDLY POSITIONED IN A BODY OF WATER, MEANS FOR INJECTING AN ADHESIVE MATERIAL BETWEEN SAID SECOND CONNECTING ELEMENT AND THE MOORING ELEMENT FOR PERMANENTLY FIXING SAID SECOND CONNECTING ELEMENT TO THE MOORING ELEMENT FIXEDLY POSITIONED IN A BODY OF WATER, AND NONDESTRUCTIVE RELEASABLE FASTENER MEANS FOR COUPLING AND RECOUPLING SAID FIRST AND SECOND CONNECTING ELEMENTS TOGETHER AT THE SAME POINT ALONG THE LENGTH OF THE FIXEDLY POSITIONED MOORING ELEMENT AND SAID SECOND CONNECTING ELEMENT BENEATH A BODY OF WATER WHEREBY SAID FIRST CONNECTING ELEMENT IS PERMANENTLY FIXED TO THE OFFSHORE WELL SERVICING FACILITY AND SAID FIRST AND SECOND CONNECTING ELEMENTS ARE RELEASABLY COUPLED TOGETHER PRIOR TO BEING POSITIONED BENEATH THE SURFACE OF A BODY OF WATER WITH THE OFFSHORE WELL SERVICING FACILITY, SAID FIRST CONNECTING ELEMENT BEING FULLY SALVAGEABLE WITH THE OFFSHORE WELL SERVICING FACILITY TO WHICH IT IS PERMANENTLY FIXED BY THE NONDESTRUCTIVE UNCOUPLING OF SAID FIRST AND SECOND CONNECTING MEANS WHEN THE OFFSHORE FACILITY IS TO BE REMOVED.

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