US2901890A - Submarine structure - Google Patents

Description

Sept. 1, 1959 Filed April 26 1957 F. E. HUTCHISON 2,901,890

SUBMARINE STRUCTURE :s Sheets-Sheet 1 Fran/r Hu/cfi/Jwn INVENTOR.

ATTOR/Vf) Sept. 1, 1959 F. E. HUTCHISON SUBMARINE STRUCTURE 3 Sheets-Sheet 2 Filed April 26, 1957 Pvt X \NWM Frank E. Hu/c/wson IN VENTOR.QM 6. FM

Sept. 1,- 1959 F. E. HUTCHISON 2,901,890

' I SUBMARINE STRUCTURE Filed April 26, 1957 3 Sheets-Sheet 3 F/Q'HA f. fluzc/i/Jon INVENTOR.

United States Patent Patented Sept. 1, 1959 Free SUBMARINE STRUCTURE Frank E. Hutchis'on, Houston, Tex.

Application April 26, 1957, Serial No. 655,333

19 Claims. (Cl. 6146) My present invention relates to a method and apparatus for erecting in place a submarine structure. It is particularly useful in the construction of drilling platforms, offshore radar stations, and similar structures which re quire a temporary or semi-permanent marine installation. My invention possesses particular utility in deep water drilling operations and may be successfully employed in depths on the order of 600 feet.

In the field of offshore or marine drilling operations in the oil industry, work is presently confined to those locations in which the depth of water does not exceed the practical working depth for divers. It is inevitable that the increasing demand for oil reserves will drive the searchers into greater depths, and those problems which are presented by increasing amounts of overlying water must be overcome. The prefabricated structures and submersible drilling barges which have been successfully employed in shallow depths will not answer the new demands, for they are lacking in size or strength or both. Modification of old equipment and techniques would be impractical if not impossible for a number of reasons. The most compelling of these is that previous structures commonly have required some of the fabrication or erection work to be done at or near the ocean bottom. This method of construction becomes increasingly diflicult at greater depths, for the period during which divers may remain submerged decreases as the water pressure increases, and a point is soon reached below which their use becomes impractical.

Accordingly, it is an object of my invention to provide a practical method and apparatus for erecting in place a submarine structure in any depth of water which may be encountered over our continental shelves.

More specifically, it is an object of my invention to provide a method and apparatus for erecting in place a submarine structure in a manner which does not require the use of divers at difircult or impractical working depths.

It is a further object of my invention to provide a method and apparatus for holding a vertical member erect on the marine floor by means of lateral supporting structure bearing against the marine bottom at a number of points spaced therefrom, whereby the vertical member is supported at a number of points along its length by mutually independent elements.

It is a further object of my invention to provide a method and apparatus for laterally supporting a vertical member on the marine floor whereby it subsequently may be moved vertically relative to its supports and embedded in the marine floor.

It is also an object of my invention to provide a method and apparatus for erecting in place a marine structure in a rapid manner so as to avoid a prolonged construction period during which the structure and workmen are exposed to adverse weather conditions.

It is also an object of my invention to provide an improved submarine bearing plate unit for the purpose of insuring increased bearing capacity and resistance to lateral loads.

In carrying out my invention I employ a vertical member extending from the marine bottom to a suitable erection vessel such as a barge. Support members are attached at the surface about this vertical member and are guided thereby while they are lowered down the length thereof. Each of the support members has a central body adapted to encircle the vertical member, and a member of downwardly extending legs attached thereto which contact the marine floor to provide lateral support for the vertical member in all directions. A convenient method and structural arrangement is provided whereby the downwardly extending legs become self-adjusting to compen sate for variations in height of the ocean floor. Such innovation includes means which may be controlled from the working vessel to institute and/or control vertical movement of each of the downwardly extending legs relative to the central body. Thus each may seek out a firm bearing on the ocean bottom independently of the others. My invention includes a further step whereby the vertical member subsequently may be lowered through the support members into a firm bearing position on the ocean bottom and cemented into place, thereby providing increased permanence and stability.

This specification and the attached drawings present the principles and one embodiment of my invention. The apparatus and methods herein described may be employed in numerous installations in which convenient erection techniques are desired in lieu of or in addition to the conventional methods of submarine fabrication by divers.

In the drawings, Fig. 1 is a side view in partial crosssection of a complete installation made possible by the use of the invention disclosed herein;

Figs. 2 and 3 illustrate the means which I employ for holding erect the vertical member and adapting the support members to an uneven floor, and further illustrate the sequence of construction;

Fig. 4 is an enlarged section along line 44 of Fig. 1;

Fig. 5 is a section along line 5-5 of Fig. 4;

Fig. 6 is a typical enlarged section of the lower portion of one of the support member legs and attached bearing plate;

Fig. 7 is a sectional elevation of a modified bearing plate unit adapted for attachment to the lower ends of the legs; and

Fig. 8 is a section alongline 8--8 of Fig. 7.

Referring now to Fig. l, a marine drilling structure erected in accordance with my invention comprises a centralvertical member 1, which serves as the nucleus or trunk of the structure. At intervals along its length are slidably mountedsupport members 2, 3 and 4, numbered from bottom to top. Each of these members comprises acentral body 5 and several, preferably four, downwardly extendinglegs 6 pivotally mounted thereon at equal intervals about its periphery. Each of thelegs 6 bears against the marine floor at a convenient point and acts as a shore against thecentral member 1. Thelower end 7 of thecentral member 1 may be set into the marine floor by drilling and underreaming and there secured by aconcrete base 8.

So much of the structure as has been described constitutes the basic elements of my submarine structure. These members provide a secure base upon which additional structure may be erected if desired. Fig. 1 illustrates but one example of such a superstructure. In this embodiment each support member has four pivotally mounted upwardly extending arms 9 spaced about the periphery ofcentral body 5. These members provide support points'above the surface of the Water for erection of a suitable platform 10'. Mounted on the platform is shown a conventional drilling rig 11. The structure of Fig. 1 is intended to be merely illustrative of the possibilities afforded by this type of construction. It will be apparent that a satisfactory platform could be erected in a number of different ways. For example, a small Working surface could be positioned atop the central in a mushroom fashion, and theresupported by inwardly inclining ilegsattached to additional bodies about the vertical member or the vertical member itself. Also, a satisfactory platform could be based on vertical columns attached at any point along the length of downwardly extending :legs. Other and equally suitable methods of providing a surface platform will occur to one versed in this art, depending on the desired characteristics of the complete installation.

The sequence of operation is best illustrated in Figs. '2 and 3. Initially, thevertical member 1 is lowered to the ocean floor'from a working vessel. It would not be 'necessary to bring the fully assembled member out to theworking location. Instead, it could be brought out in a number of sections for surface assembly by welding or other means during the lowering operation. As soon as the vertical member comes to bear on the :ocean :bottom, the next step begins. Thefirst support member 2 is attachedwith thevertical member 1 passing through thecentral body 5. This member is lowered until its legs6 reach the ocean floor. This operation may be combined with the first by providing asuitable stop 12 at the lower portion of thevertical member 1 .and allowing the lower support member 2 :to be lowered in conjunction with thevertical member 1. This device willinsure a certain amount of lateralstability as soon .as the central member reaches the bottom if thestop 12 is suitably positioned with respect to the length of the legs :6.

Support members 3 and 4 are introduced into the structure in a similar manner as they are first attached about the .surface end ofvertical member 1 and .then lowered down the length thereof until their respective legs bear against the marine bottom. All of the legs are maintained at substantially the same vertical angle relative tothe vertical member during descent and their length increases progressively with the :order in which their associated central body is introduced into the structure. Therefore each support member bears against the bot- ;tomat .-a greater distance from the vertical member and the vertical member at a higher point than its predecessor. It is apparent that any desired number f support members may be used, depending on the depth of the water and theover-all rigidity of the vertical member.

The foregoing method will satisfactorily provide all around lateral support on a level marine floor. If the 'zfloor is not level, the usualsituation, a suitable adjustment could be made in the length or angle of suspension of the legs .to compensate for these inequalities if their magrnitude were determined .prior to the :beginning of .oper- .ations. However, I prefer to provide pivotally mounted legs .and releasable means, to be described in subsequent -paragraphs, :which allows the support legs to be self-compensating for-varying marine floor topography.

Referring now to Fig. 3 which shows the basic elements of my invention in place, thelegs 6 have each sought and found a suitable bearing point .on the ocean floor. At this timethe vertical member has become laterally supported to a point considerably above the ocean :floor. Therefore, asa final step to completionof the struc- .ZtlllTQfthB vertical member may be sunk into the ocean bottom cemented into place. This final operation may :be .perfoiined if the desired permanence of the structure ia'ndthezbottom .conditions indicate its necessity. As the member is slidable within the collars, it may be :some small distance into the bottom solely by qntessurefrom above, .or a rotary movement may be imparted -to itxif theshape permits. Auxiliary jetting means ilcould'ibe employed toiforcea depression of suitable size rtoireceivethe {lower end, {or a drill and an underreamer eould introduced through a vertical member which =ho'llow toprovide a suitable hole. A choice of these conventional methods can be made, dependent on the bottom conditions and the permanence of the installation. It is apparent that the vertical member could be countersunk to any desired depth while additional sections which add to the length of the vertical member are attached at the marine surface. The concrete may be introduced through a channel within the central member or other convenient means as circumstances indicate.

The above and other considerations peculiar to a specific installation might indicate a choice of shape for the vertical member. For marine drilling I prefer to employ a hollow cylindrical section, for it provides equal structural rigidity in all directions, a central shaft or casing through which subsequent underreaming and drilling operations may be conducted, and a convenient conduit througdt which concrete or other stabilizing medium may be introduced. When concrete is so introduced, it may be forced outward by pressure from above to form thebase 8.

The novel structure ofsupport members 2, 3 and 4 is a part of my invention. Fig. 4 illustrates a portion of a typical support member adapted to encircle a cylindrical vertical member. As indicated above the several support members are identical with .the exception of'the length of thelegs 6 which increases with the order in which the member is to be introduced into the structure. The central body of the support member of Fig. 4 comprises acollar 14 which is formed by identicalsemicircular bands 15. Each of the bands has a radial flange 1.6 at each'end, and cooperatingnuts 17 and bolts 1-8 act between the flanges to hold the hands together. Thus the support member may be assembled and introduced over the upper end ofthevertical member 1, or it may be assembled about the vertical member at any convenient point intermediate its ends.

The bands describe a circle .of substantially greater diameter than the vertical member. Within each of the bands is a number :ofresilient shoes 19 which are attached directly 'to-rhe inner face of the bands or :preferably to channel sections 2.0 which are welded to the inner face. The inner surface 21 .of .each of theshoes 19 is shaped to conform to an 'arcuate section of :thevertical member 1 in sliding contact therewith. The shape of the .bauds 15 and/or the inner surface 21 of theshoes 19 may be altered to conform to any desired cross-section ofvertical member 1.

Theresilient shoes 19 add to the QVcHIill flexibility of the structure. The freedom'frorn. rigidity afforded by this device and the .pivotal mounting .of the legs is important in a structure which is subjected to overturning loads from alldirections. The :Various members are free to adapt themselves to react loads compressively along their strongest axis rather than in shear or bending. 'In addition, the shoes prevent sliding metal-to-metal contact which would be ruinous in salt water, and allow the support members to slide by welds or other surface inequalities in the vertical member.

Each of the downwardly extendinglegs 6 is attached about the outer periphery of the bands '15 by pinsZZ which are secured 'between a suitable pair oflegs 23. Each leg is held at some angle away from the axis of thevertical member 1 by a retainingbar 24 which is held bypin 25 betweenears 26 onthe collar a-nd'extends outward to asuitable bearing recess 27 on its associated leg, within which it is received. The Weight of-the leg acting downwardly holds this bar inan engagerhpos tion during the descent of the support member to :theocean floor. When any one of the legs-contacts the bottom, the descent of the collar is arrested at which time each of the legs may be-raised slightly by some suitablemeans such as that illustrated in Fig. 6,- in which aca bleZS extends through a lifting l-ug 29 on the bearing plate. When the weightof the leg :is r'eleased from't-he retaining bar, it moves downward by'its own weight outof therecess 27 and out of engagement with the leg, swinging all about pin 25'. Thus when thecable 28 is released, the leg will rotate downward about its pivotal mounting until it bears against the ocean floor. It is apparent that this arrangement eliminates any necessity for elaborate sounding to determine the topography of the ocean bottom. Each leg is free to seek out its most convenient bearing level without adjustment either prior to lowering or at the bottom.

The retainingbar 24 and its associated parts could be eliminated from the structure successfully by utilizing thecables 28 to control the proper vertical angle of the legs during descent, but I prefer to use the retaining bar for ease of operation.

The cable preferably should be attached to the legs at the surface before the lowering operation is begun. By using a cable which is merely looped through or around liftinglug 29, it is possible to lift the legs enough to release the retainingbar 24 by pulling both free ends of the cable, and then recover the cable after its purpose has been served by releasing one end at the surface and drawing the cable longitudinally through the point of attachment.

Referring now to Fig. 6, the bearingplate 30 is attached to the outward end of each of the legs by means ofpivot pin 31 which passes through the leg and the mounting lugs 32 on the top of the bearing plate. The resulting pivotal connection allows the bearing plate to seat in a position normal to the marine floor without regard to the position of the leg.Flanges 33 sink into the bottom to provide maximum resistance to lateral loads. In a soft bottom it may be desirable to drive the bearing plates into firm engagement. For this purpose the top of thelugs 32 is shaped to form a drivingblock 34. Thecable 28 may be used to guide a set of conventional drilling jars or an air hammer which will deliver a series of impacts to the driving block to seat the bearing plate. Subsequently a conventional dart bailer may be similarly guided into position to dump concrete over the seated bearing plate to secure its location.

Figs 7 and 8 illustrate a modified structure for attachment to the ends of thelegs 6. On a soft bottom it may be desirable to provide a bearing plate unit which offers increased resistance to vertical loads without sinking or settling into the marine floor and also incorporates structural features necessary for resistance to lateral loads. In these figures, aninverted hemisphere 35 has an upper attachinglug 36 through which pin 37' pivotally secures the lower end ofleg 6. Thus theopen bottom 38 of the hemisphere will always lie in a horizontal plane during lowering and it will seat against the marine floor in such a manner that the entire bottom area will be utilized to resist bearing loads. The hemisphere will settle into the soft bottom some small distance and compress the air and/or sea water which is trapped within it. The resulting pressure resists bearing loads and creates a highly efficient bearing plate.

Located within thehemisphere 35 is ananchor member 39 which is rotatable about theshaft 40. Theshaft 40 is journaled intoconvenient mountings 41 in the hemisphere. This arrangement allows the anchor member to be carried within the hemisphere for convenient storage and handling as shown by the object lines in Fig. 7. When the unit is lowered into the water, the hemisphere will align itself in a horizontal position and the anchor member will extend vertically below the hemisphere as shown by the dotted lines in Fig. 7. After the unit seats on the'bottom and lateral loads are communicated to it through its associated leg, theanchor member 39 will bear against theanchor lug 42 within the hemisphere. Thus a rigid vertical bearing surface will extend into the marine floor to resist lateral movement. The lower edges of the hemisphere will have vsunk a small distance into the bottom to provide some additional measure of lateral stability.

I prefer to use a hemispherical section for the bearing plate because it provides a maximum bearing area and a downwardly extending flange about its perimeter which tends to trap'within it the soft matter forming the marine floor. Thus the material cannot squeeze out and allow the unit to settle. Instead the plate will float on the bottom in which position it is readily recoverable. It is apparent that any shape of bearing plate could be employed to obtain the advantages herein outlined so long as it included a continuous downwardly extending flange on its bottom to define a space for entrapment of a small amount of the soft matter on the marine floor.

With the modified unit of Figs. 7 and 8, it will not be necessary to drive the plate into the bottom or anchor it with concrete. Thecable 28 may be secured to the upper attachinglug 36 and employed in the manner herein. described to lower the legs into position on the bottom.

As indicated, the structure thus formed may be temporary or semi-permanent. When its usefulness has ceased, it may be recovered by reversing the procedure herein outlined. Each of the support members may be raised successively to the surface and disassembled, beginning, of course, with the uppermost member. The vertical member then may be shot oif its concrete base if necessary and lifted again to the surface.

If it is desired to provide a more permanent structure, suitable steps may be taken to render the structure more stable. For example, a net may be drawn about the outermost legs, completely enclosing them, or the lifting cables may be left in place and a net interlaced among them. Into the cylindrical or conical volume thus formed, rock or other suitable stabilizing medium may be introduced. Such steps would create an artificial island of almost indefinite life, due to the increased protection from the attack of wind and wave.

The size and shape of the central member may be varied to meet the demands of the location. Itf desired for extensive drilling, this member could be of a size, up to twenty-four feet in diameter, which would allow an internal working area suitable to accommodate six wells as shown in Fig. 4. By means of directional drilling, a large producing area could be tapped from a single platform. Other adaptations of this invention will occur to one skilled in the art of submarine construction. Therefore, it is desired to protect by the appended claims all forms of the invention falling within their scope.

I claim:

1. A submarine structure comprising a vertical member adapted to extend from the marine floor to the marine surface, and a number of mutually independent lateral support members disposed at intervals along the length of said vertical member, each of said support members comprising a central body slidably disposed about said vertical member and a plurality of legs attached about the periphery of said central body, each of said legs extending downwardly and outwardly relative to said vertical member and adapted to bear directly against said marine floor.

2. A submarine structure comprising a hollow cylindrical vertical member adapted to extend from the marine floor to the marine surface, a number of mutually independent lateral support members disposed at intervals along the length of said vertical member, each of said support members comprising a collar disposed about said vertical member, a plurality of resilient shoes disposed within said collar adapted to maintain said collar in a spaced relationship to said vertical member, and a plurality of legs mounted about the periphery of said collar for pivotal movement in a vertical direction relative there.- to, each of said legs extending downwardly and outwardly relative to said vertical member and adapted to bear directly against said marine floor.

3. In a submarine structure, a support member adapted to provide lateral submarine support for a vertical member resting on the marine floor comprising a centralbody adapted to encircle said vertical member in sliding contacttherewith anda'plurality of legs attached about the periphery of said central body, each of said legs being adapted for vertical pivotal movement relative to said central body and extending downwardly and outwardly relative thereto and adaptedto beardirectly against said marine floor. 1

4. 'A support member as defined in claim '3 and comprising in addition a number of independent retaining members, each of said retaining members interconnecting one of said legs with said central body and being adapted to maintain said one leg at a fixed downward angle relativeto said central body, each of said retaining members being releaseable'to permit said vertical pivotal movement of the said one leg'ina downward direction.

" 5. In a submarine structure, a' support member adapted to provide lateral submarine support (for a hollow cylinvertical member resting on the marine floor comprising a collar adapted to encirclesaid verticalmember, a plurality of resilient shoes disposed within said collar adapted to maintain said collar in a spaced'relationship to said vertical member, and a plurality of legs attached about the periphery of said collar, each of said legs extending downwardly and outwardly'relative to said collar and adapted to bear against said marine floor.

' 6,. A support member'as defined inclaimS including pivot means connecting each of said legs'to said collar whereby each of said legs is adapted forvertical pivotal movement relative'to said collar.

7. A'support member asdefinedinclaim 6 andcompu'ising'in addition a plurality of independent retaining members, each of said retaining members interconnecting oneotf said legs with said collar and being adapted to maintain said one leg at a fixed downward angle relative to said collar, each of said retaining members being releaseable to permit said vertical movement of the said one leg in a downward direction. g "8. In a submarine structure, a support memberadapted to providelateral submarine support for a vertical member resting on the marine floor comprising a central body adapted to encircle said vertical member in'sliding contact therewith, a plurality of legs attached about the periphery of said central body, each of said legs being adaptedfor vertical pivotal movement relative to said central body and extending downwardly and outwardly therefrom to bear against said marine floory a bearing plate unit pivotally. attached to each of .said legs at the outward end thereof, each of said bearing plate units comprising a bearing plate having a continuous downwardly extending flange to define an inner space on the bottom thereof, ananchor member carried "within said inner space and pivotally attached to said bearing plate, 'saidanchor member being adapted to extend vertically downward below said bearing plate flange when said bearing plate unit is in contact with said marine floor, andan anchor stop member on said bearing plate to define ysaid vertical position of said anchor member.

v9. In a submarinestructure, a submarine bearing plate unit adapted for resistance to both vertical and horizontal loads comprising a bearing plate having a continuous downwardly extending flange to define an inner space on the bottom thereof, an anchor member carried within said space and pivotally attached to said bearing plate, said anchor member being adapted to extend vertically downward below said bearing plate flange when said bearing plate unit ,is in a substantially horizontal position, and an anchor stop member .on said bearing plate to definesaid vertical position of said anchor mem- 10. In a submarine structure, a submarine bearing plate unit adapted for resistance to both Vertical and horizontalloads comprising a hemispherical bearing plate, an a hor member .carried within sai hemi ph e and pivotally mounted thereon whereby it may rotate into a substantially vertical position to extend below said bearing plate when said bearing plate is in a substantially horizontal position, and a stop member on said hearing plate limiting said rotary-movement to define said vertical position of said anchor member.

11. A marine platform comprising a vertical member adapted 'to extend from the marine floor to the marine surface; a number of lateral support members disposed at intervals along the'length of said vertical member, each of said support members comprising a central body slidably disposed about said vertical member, a plurality of downwardly and outwardly extending legs attached about the periphery of said central body and adapted to bear against said marine floor, and a plurality of upwardly and outwardly extending arms attached about the periphery of said central body and adapted to extend to said marine surface; and a platform atop said vertical member and bearing against said arms.

'12. The method of providing lateral submarine sup port for a vertical member bearing on the marine floor comprising the steps of lowering a first independent support member along said vertical member until it bears against said marine floor at a plurality of points spaced around and substantially equidistant from said vertical member and embraces said vertical member at a point susbtantially above said marine floor, and repeating step one with a series of similar but progressively larger independent support members whereby said vertical mem ber is independently supported at progressively higher points along the length thereof.

'13. The method of erecting a submarine structure comprising the steps of lowering a vertical member to the marine floor, lowering a first independent support member along said vertical member until it bears against said marine floor at a pluarlity of points spaced around and substantially equidistant from said vertical member and embraces said vertical member at a point substantially above said marine floor, and repeating step two with a series of similar but progressively larger independent support members whereby said vertical member is independently supported at progressively higher points along the length thereof.

14. The method of claim 13 and the additional step of producing downward movement of said vertical member relative to said support members whereby it is introduced into said marine floor.

15. The method of providing lateral submarine support for a vertical member bearing on an uneven marine floor comprising the steps of lowering along said vertical member a support member having a number of surface controlled vertically adjustable bearing members extending downwardly therefrom, arresting the descent of said support member upon its arrival adjacent the highest point of said marine floor, and adjusting each of said bearing members for contact with said marine floor.

16. The method of erecting a submarine structure on an uneven marine floor comprising the steps of setting a vertical member on said marine floor, lowering along said vertical member a support member having a number of surface controlled vertically adjustable bearing members extending downwardly therefrom, arresting the descent of said support member upon its arrival adjacent the highest point of said marine floor, and adjusting each of said bearing members for contact with said marine floor.

17. The method ofclaim 16 and the additional step of producing downward movement of said vertical member relative to said support member whereby it is introduced into said marine floor.

'18. The method of erecting a submarine structure on an uneven marine floor comprising the ,steps of setting a vertical member on said marine floor, lowering along said vertical member a first support member having a number of surface controlled vertically adjustable bearof producing downward movement of said vertical meming members extending downwardly therefrom, arresting her relative to said support members whereby it is introthe descent of said first support member upon its arrival duced into said marine floor.

adjacent the highest point of said marine floor, adjusting each of said bearing members for contact 'with said 5 References Cited in the file of this patent marine floor, and repeating steps two and three with a UNITED STATES PATENTS series of similar but progressively larger independent support members whereby said vertical member is inde- 2,210,408 Henry Aug. 6, 1940 pendently supported at progressively higher points along 2,637,978 Evans et a1. May 12, 1953 the length thereof. 10 2,799,369 Walton July 16, 1957 19. The method ofclaim 18 and the additionl step 2,804,766 Landman Sept. 3, 1957

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