US3183676A

US3183676A - Mobile sea platform

Info

Publication number: US3183676A
Application number: US63928A
Authority: US
Inventors: Robert G Letourneau
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-10-20
Filing date: 1960-10-20
Publication date: 1965-05-18
Anticipated expiration: 1982-05-18

Description

May 18, 1965 R. G. L E TOURNEAU 3,183,676

MOBILE SEA PLATFORM Filed Oct. 20, 1960 Sheets-Sheet l May 18, 1965 R. G. LE TOURNEAU MOBILE SEA PLATFORM 6 Sheets-Sheet 2 Filed Oct. 20, 1960 May 18, 1965 R. G. LE TOURNEAU 3,183,676

MOBILE SEA PLATFORM Filed oct. 2o, leso e sheets-sheet s INVENToR. H055# 6.? Le nwwmu BY @W f%%/J May 18, 1965 R. G. LE TOURNEAU 3,183,676

MOBILE SEA PLATFORM Filed Oct. 20, 1960 6 Sheets-Sheet 4 May 18, 1965 R. G. LE VTOURNEAU 3,183,676

MOBILE SEA PLATFORM Filed Oct. 20, 1960 6 Sheets-Sheet 5 ELECTRIC O- coNTAc-ron Powsn ALL @Ps souRcE 125 7715 /729 L coNTAcToR morons 1L- GP GP l coNTRoL sT/mou 125 f? U 15]/ WQ g coN'rAcToR MoroRs A m lb GP n GP u 155/ 159 117 coNrAcToR MoToRs GP In GP m BY wm f 7%# #Horny May 18, 1965 R. G. LE TOURNEAU MOBILE SEA PLATFORM 6 Sheets-Sheet 6 Filed 001;. 20, 1960 United States Patent O 3,183,676 MOBILE SEA PLATFORM Robert G. LeToumeau, R0. Box 2307, Longview, Tex. Filed ct. 20, 196), Ser. No. 63,928 2 Claims. (Cl. (i1-46.5)

My invention relates generally to improvements in mobile sea platforms, and particularly to iloatable vessels which are convertible into stabilized structures over bodies of water, and is a continuation-in-part of my application S.N; 473,885, filed December 8, 1954, and now abandoned. My invention is especially applicable to off-shore or tidelands oil exploration, drilling and producing operation. Off-shore drilling platforms of the prior art of which I am aware have included the nonmobile type, built up from or supported by a permanent piling foundation, the mobile type using a sunken re-lloatable vessel as a base, and the mobile type using various arrangements of extensible and retractable spuds carried by a barge-like vessel. The problems attending the design of a suitable off-shore drilling platform are indeed formidable. Such a platform must be capable of supporting several thousand tons weight well above the water surface with a high degree of stability, withstanding the ravages of winds, waves, and tides for all normally expected conditions. Fixed piling type platforms are subject to the serious disadvantage that their entire cost must be recovered from operations conducted at a single location. The sunken vessel type drilling platform, while used rather extensively in inland and protected water areas, does not olfer promise of suiiicient stability for off-shore operations. The mobile type platform carrying spuds that are extensible and retractable has been considered the most desirable type platform for olf-shore operations.

It is a general object of my invention to provide an improved floatable vessel which is convertible into a stabilized structure over a body of water.

Another object of my invention is to provide an irnproved hull structure for certain barge-like vessels.

Another object of my invention is to provide an improved oatable Spud-carrying vessel having effective means for raising and lowering the vessel on the spuds.

Another object of my invention is to provide an improved tloatable spud carrying vessel wherein the vessel can be raised or lowered on the spuds within a minimum period of time.

Another object of my invention is to provide a mobile type Spud-carrying olf-shore drilling platform of simple but extremely rugged construction.

Another object of my invention is to provide a mobile type Spud-carrying olf-shore drilling platform having a relatively low rst cost.

Another object of my invention is to provide a mobile type Spud-carrying off-shore platform wherein the total platform load is automatically maintained in equally distributed relation among the platform supporting elements.

Additional objects and advantages of my invention will be apparent from the following description of a preferred embodiment, taken together with the accompanying drawings in which: l

FIGURE l is a diagrammatic perspective view showing the general appearance of an off-shore drilling barge embodying principles of my invention;

FIGURE 2 is a plan View showing the vessel hull, spud wells, and spuds of a drilling platform of my invention, with a portion of the hull cut away to show corrugated transverse bulkheads;

FIGURE 3 is a side elevational view of the hull structure shown by FIGURE l, showing extended spuds;

Fice

FIGURE 4 is a front elevational view of the structure shown by FIGURE l, but with the spuds fully retracted;

FIGURE 5 is a perspective View of a Spud well;

FIGURE 6 is an enlarged fragmentary view showing details of the arrangement of electric motors and gear boxes in a spud well, operating on a rack fixed to a portion of a Spud tower;

FIGURE 7 is an enlarged plan view of a spud well with the cap plate and upper box beam removed, and showing a spud in the spud well;

FIGURE 8 is a schematic block diagram of the electric control system for the spud raising and lowering mechamsm;

FIGURE 9 is a perspectiveview showing a modified vessel structure embodying principles of my invention;

FIGURE l0 is a perspective view showing another modified vessel structure embodying principles of my invention; and

FIGURE l1 is an enlarged perspective view, partially broken away, showing one of the electric motor and gear box units of FIGURE 6.

Turning now to the drawings, in FIGURE l there is shown a general arrangement of drilling apparatus on the deck 12 of a barge-like vessel 11. A derrick 13 is mounted over a slot in the forward end of the vessel 11 so that the vessel may be moved out without interference with the permanent well structure. A draw-works 15 is disposed on the side of the derrick 13 rearwardly of the slot. A housing 17 for power plant, equipment storage, etc., extends across the rear end of the deck 12. Pipe racks 19 are located off the forward end of the deck 12 on either side of the vessel slot. The specific arrangement of drilling apparatus forms no part of my invention, and it isv understood that various arrangements of drilling apparatus, equipment, quarters, etc., may be made, according to preferences and needs of the particular drilling concern. FIGURE l also shows three spud wells 21, two of which are fixed to opposite sides of the vessel 11 adjacent its forward end, the third being xed to the center portion of 'the vessel rear end. A spud 23 comprising a tower portion 25 and a caisson portion 27 is carried by each spud well 21.

With reference to FIGURES 2, 3, and 4, it will be seen that the vessel hull 11 is made up of a plurality of joined cylindrical sections. The hull comprises two parallel spaced longitudinal sections 29 joined to two spaced

transverse sections

21, 23. Each longitudinal section 29 comprises a pair of

major cylinder segments

35, 37 made of heavy steel plate, having their straight edges contiguously matched and joined as by welding to form strong water-tight joints. The forward ends of the longitudinal sections are closed by welded heavy steel plate caps 39 which are shaped to minimize water resistance during movement of the vessel 11. The transverse sections are heavy steel plate cylinders. The rear transverse section 33 closes the rear end portions of the longitudinal sections 29, The rear transverse section and the rear end portions of the longitudinal sections are shaped so as to be contiguously matched, and are welded to make strong wa-ter-tight joints. The forward transverse section 31 is disposed to form the rear side of the derrick slot, and has its ends shaped to contiguously match the inner faces of the longitudinal members to which it is welded to make strong water-tight joints. The vessel hull secn tions are re-enforced by corrugated bulkheads 41 made of heavy steel plate disposed at spaced intervals transversely of the hull sections and shaped to conform with the hull section inner peripheries and welded thereto. The space totally enclosed by the hull sections is oored to form a lower deck 43 made up of a pair of parallel spaced heavy steel plates 4S, 47 separated by, and fixed 3 to, rigid truss work 49. The

plates

45, 47 are sized to bear contiguously against the hull sections below their center lines and are welded thereto.

As hereinbefore mentioned, the vessel hull 11` carriesy slightly outwardly, to enhance the structural character-M istics of the assembly. The inner side walls are made up of vertical panels 53 to form seven sides of a generally octagonal figure. The open side of the spud well tits on to the Vessel hull 11. The inner side wall 54 opposite the open side is common to the outer side wall. Next adjacent sides- 61, 63 of the octagonal figure present plane surfaceseach having a vertical gap 55 at its center, which gap forms the open side of a slot to receive spud gear racks, as will be hereinafter more fully described. The next adjacent

inner walls

59, 65 of the generally octagonal ligure are disposed slightly outward to enhance the structural strength characteristics of the assembly. The next adjacent

inner walls

57, 67 present plane surfaces each having a vertical gapy for the purpose above-men-l tioned. A pair of vertical trough shaped members 69, '71 of generally trapezoidal cross-section, have their open edges welded to the inner face of the spud well outer wall 54 that lies opposite the Spud well open side. Each of these trough-shaped members serves as a supporting structure for one edge of each of a pair of spacedparallel vertically disposed extra

heavy plate members

73, 75 which in turn form the sides of a slot which receives a spud gear rack 77. Supporting structure for the side Walls of each of the other two Spud well slots is provided by a

vertical box beam

79, 81. The box beam is held rigid by two

heavy verticalsteel plates

83, 85 one of which extends from the box beam to the adjacent outer side Wall of the spud well, and the other of which extends from the box beam towardl the vessel hull. Heavy

steel cap plates

87, 89 cover the top and bottom of the Spud well structure and are welded thereto. The outer edges of the cap plates are rectangular, while the inner edges are octagonal, to conform to the general shape of the spud well transverse section. A pair of parallel spaced

box beams

91, 93 are welded respectively to the upper and lower portions of the outer wall 54 of the spud well opposite the open side. All of the Vedges of the Spud well on the open side are shaped to conform to the contour of the vessel hull, and are welded thereto.

The spud towers 25 are fabricated of welded steel pipe and havev a generally square cross-section. Four parallel spaced vertical `'columns 95 made of large diameter pipe form the four corners of each spud tower. The vertical columns are Vheld rigidly by latticed truss-work 97 made of smaller diameter pipe. The spud caissons 27 are large cylindrical tanks fabricated by welding heavy steel plate members. The ends of the tanks are closed by heavy steel caps 99, 101 having a generally conical shape. The tanks have a diameter just small enough to permit them to be retracted into the spud wells. The length of the tank is dependent upon the gross weight of the vessel and its load, for reasons to be hereinafter explained.

The spud tower extends down into the caissons and is.

:supported by the caisson bottom cap.

Each Spud tower vertical column 95 carries a gear rack 77 along substantially its entire length and which extends into a Spud well slot, as best shown by FIGURE 6. The gear racks 77 of diagonally opposite vertical columns of a Spud tower lie in a common plane. The

side walls

73, 75 of the spud well slots are made `of extra heavy steel plate material. Electric motor and gear box units 103 are @im 111 Staggered relation to the outer faces of the slot side walls. Each electric motor 165 drives a gear box 107 which has an input pinion 103 and an output pinion 139 extending through a hole in the slot `side wall to mesh with the gear rack 77. Each electric` motor is provided with an electromagnetiefriction brake mechanism 111 which isl automatically engaged when'its motor is de-energized. Details of a typical electromagnetic friction brake of the general type suitable for .use in this application are shown by my U.S. Patent Number 2,756,- 846, issued July 3l, 1956. The electric motors are controlled from a single control station. FIGURE 8 is a schematic block diagram of the motorcontrol system. All of the motors on a particular spud tower `are connected in parallel. In FIGURE 8, the block 113 labelled MOTORS Gp. I represents all of the motors on one spud tower, while the block 115 labelled MOTORS Gp. Il represents all of the motors on a second spud tower, etc. Power is supplied from the block 119 labelled ELECTRIC POWER SOURCE lthrough a main contactor 121 labelled CONTACTOR ALL Gps, Yto all groups simultaneously, and also through an

individual contactor

123, 125, 127 for each group, labelled CON- TACTOR'GpfI, etc. All contactors have front and back contacts so that the motors maybe reversed. A control station provides toggle switch control of all contactors. Each toggle switch control solenoids which in turn operatefthe associated contactor in the desired direction.k |There is a toggle switch131 labelled A" to control `the main contacter 121, and toggle switches`135, 137, 139 labelled 1, Il, III to control the

respective group contactors

123, 125, 127. Each toggle switch has an up Uf neutral N and down D position. If the toggle switch A is up, all of the motors on-all of the spud towers are energized and operate to raise the ent'ne vessel hull -on the spuds l(or lower the spuds). If the toggle switch A is inthe down position, all of the motors on all ofthe spud towers are energized and workv simultaneously to lower the vessel hull (or raise the spuds). When it is desired to raise or lower vone Spud only, then the appropriate group toggle switch is closed in the proper direction. Y i

The dimensions of the vessel hull, spud wells, spuds, etc., will of course depend upon theV specific application for which a particular apparatus isdesigned. Representative approximate dimensions for an ofi-shore drilling apparatus capable of operation in up to 80 feet of water are as follows: vessel hull length, 140 feet; vessel huil width, 8O feet; width of hull longitudinal side members, 30 feet; diameter of vessel hull cylinders and cylinder segments, 2()` feet; spud well width overall, 36 feet; spud well depth, 20 feet; spud tower, distance between adjacent vertical columns, 2O feet; spud towers, length overall, feet; caisson diameter,.28 feet; caisson length, 38 feet.

In the prior art, it has ,been the practice to desi-gn spud caissons to rest with minimum penetration on the water door. VSuch design. does not provide the optimum degree of stability, and is especially unsuitable in locations where the foundation medium is poor. Applicants caissons on the other hand are actually designed to obtain substantial penetration in the foundation medium. For areas where the foundation medium is goed and the major caisson supporting factor is end bearing, applicants caissons penetrate sufciently to obtain substantial support against lateral forces. In some extensive areas, a poor foundation medium obtains for feet or more below the water loor. In such areas,rapplicants caissons will penetrate the foundation medium, and the relationship between caisson displacement and caisson loading will be made such that the caisson will actually lloat in the foundation medium. Etfective caisson displacement is made variable according to the density of the foundation medium by providing for introduction and removal of liquid ballast to and from the caissons at will. Various means for introduction and control of such liquid ballast are well-known and are therefore thought not to require detailed description or illustration herein. By way of example, liquid ballast may be introduced to a caisson via one of vertical columns of the tower structure7 and may be forced out of the caisson by means of compressed air, also introduced Via a column of the tower structure. Means are also well known for jetting out about caissons to facilitate raising them, or to improve footing conditions.

The number and size of motors to be used will of course depend upon the total weight of the vessel hull and its load, and the desired rate of lift. Since motors are mounted to drive pinions meshing with gear racks on each corner of each spud tower, and are mounted on both sides of each Spud well slot, it will be apparent that for the representative dimensions given above, about 160 feet of linear motor unit mounting space is available at each spud tower. The use of multiple motors and multiple gear racks makes it possible to employ motors, gear reductions, pinions, and gear racks of a convenient and practicable size.

Appiicants vessel hull structure is simple and economical to build, and yet is extremely rugged. The structure allows the possibility of multiple compartments uncomplicated by bracing and truss-work, and suitable for temporary storage of fuel, Water, drilling mud, and production. The inherent torque tube characteristic of the hull construction renders it eminently suitable for carrying the off-side spud wells.

FIGURES 9 and 10 show modified vessel structures embodying principles of my invention. In FIGURE 9, the vessel hull 141 is made up entirely of

cylindrical hull sections

143, 145, 147, 149. In FlGURE 10 the longitudinal

vessel hull sections

151, 153 each have side portions made of major cylinder segments 155 and top and bottom portions made of minor cylinder segments, 157 all joined by welding to form a closed body. Other modified vessel hull structures will occur to those skilled in the art, without departing from the principles of my invention.

It is to be understood that the foregoing disclosure and the showings made in the drawings are merely illustrative of the principles of my invention and are not to be inter preted in a limiting sense.

I claim:

1. A plurality of Spud wells carried by a vessel hull,

a Spud in each spud well, each said spud comprising a tower structure including a plurality of interconnected vertical columns, a rack carried by each column longitudinally thereof, a plurality of gear reduction units fixed to each Well adjacent each said rack, said gear reduction units each having an output pinion in mesh with said rack, and an input pinion, an electric motor fixed to each said gear reduction unit and driving said input pinion, an electrical control system providing for selective application of power simultaneously to all of the electric motors associated with each particular spud, an electromagnetic friction brake associated with each said motor, and means for energizing said brake to release same only when said motor is energized.

2. A plurality of spuds carried by a mobile sea platform, each said spud comprising a tower structure including a plurality of interconnected vertical columns, a plurality of racks xed to said tower structure and extending longitudinally thereof, a plurality of electrically driven gear reduction units fixed to said platform adjacent each said rack and each having an output pinion drivingly engaging said rack, a plurality of electromagnetic friction brakes linked to the gear reduction units associated with each said rack and means for energizing said brakes to release them only when said gear reduction units are energized.

References Cited by the Examiner UNITED STATES PATENTS 1,648,423 11/ 27 Powelson et al.

2,210,408 8/40 Henry 61--465 2,308,743 1/43 Bulkley et al 61-46.5 2,701,036 2/55 Osborne 18S-171 2,749,776 6/56 Fischer et al.

2,756,846 7/56 LeTourneau 18S-171 2,924,077 2/ 60 LeTourneau 61-46.5 2,925,153 2/60 Hodgson 18S-171 3,044,269 7/62 LeTourneau 61-465 EARL I. WITMER, Primary Examiner.

WTLLIAM I. MUSHAKE, JACOB SI-IAPIRO, JACOB L. NACKENOFF, Examiners.

Claims

1. A PLURALITY OF SPUD WELLS CARRIED BY A VESSEL HULL, A SPUD IN EACH SPUD WELL, EACH SAID SPUD COMPRISING A TOWER STRUCTURE INCLUDING A PLURALITY OF INTERCONNECTED VERTICAL COLUMNS, A RACK CARRIED BY EACH COLUMN LONGITUDINALLY THEREOF, A PLURALITY OF GEAR REDUCTION UNITS FIXED TO EACH WELL ADJACENT EACH SAID RACK, SAID GEAR REDUCTION UNITS EACH HAVING AN OUTPUT PINION IN MESH WITH SAID RACK, AND AN INPUT PINION, AN ELECTRIC MOTOR FIXED TO EACH SAID GEAR REDUCTION UNIT AND DRIVING SAID INPUT PINION, AN ELECTRICAL CONTROL SYSTEM PROVIDING FOR SELECTIVE APPLICATION OF POWER SIMULTANEOUSLY TO ALL OF TH ELECTRIC MOTORS ASSOCIATED WITH EACH PARTICULAR SPUD, AN ELECTROMAGNETIC FRICTION BRAKE ASSOCIATED WITH EACH SAID MOTOR,