US2938353A - Submersible drilling barge - Google Patents

Description

May 31., 1960 E. R. VORENKAMP 2,938,353

SUBMERSIBLE DRILLING BARGE Filed Dec. 27, 1954 4 Sheets-Sheet 1 INVENTOR ER. VORENKAMP HIS AGENT May 31., 1960 E. R. VORENKAM-P 2,938,353

SUBMERSIBLE DRILLING BARGE Filed Dec. 27, 1954 4 Sheets-Sheet 2 FIG. 5 INVENTOR ER. VORENKAMP 14.1 HIS AGENT May 31, 1960 E. R. VORENKAMP SUBMERSIBLE DRILLING BARGE 4 Sheets-Sheet 3 Filed Dec. 27, 1954 INVEN TOR:

E.R. VORENKAMP 6 H M @1 1 HIS AGENT y 1960 E. R. VORENKAMP 2,938,353

SUBMERSIBLE DRILLING BARGE Filed Dec. 27, 1954 4 Sheets-Sheet 4 FIG. 80

I. MUD I FIG. 9 FIG. 90 FlG.9b

INVENTOR E.R. VORENKAMP HIS AGENT 2,938,353 S'UBMERSIBLE DRILLING BARGE- Egbert R. Vorenltamp, New Orleans, La., assignor to Shell Oil Company, a corporation of Delaware Filed Dec. 21, 1954, set-.No. 477,743

2 Claims. Ciel-46.5

The present invention relates to marine vessels such as floating barges for use in subaqueous drilling operations and pertains more particularly to a new type of a submersible barge for supporting the necessary well drilling equipment firmly in place above the surface of the water during drilling operations at ofi-shore locations.

During the past several years considerable interest has been shown in drilling'oil wells in otf-shorelocations,

particularly in the Continental Shelf off the shores of Texas and Louisiana. Drilling ofi-shore oiliwells is a difiicult and expensive operation necessitating the use of suitable apparatus for positioning the required drilling equipment at a safe level'above the surface of the waters in which drilling operations are being carried out. Heretofore, various types-of apparatuses havebeen proposed for use in off-shore drilling operations. These apparatuses fall into twomain classes: l) fixed platforms positioned -on piling which is driven into the ocean floor and (2) ideal drilling barge should havea hull or pontoon sufficientin size to impart stability to the barge, either when the barge is being-floated to the drilling location, or after it has been sunk to the ocean floor at said location. In designing a pontoon adapted --to be positioned onan ocean floor, it is important that the pontoon be no higher than necessary so as to reduce the area *against which wind and ocean waves or currents would act to move the barge.

At some locations off the coast of Louisiana, there is no solid bottom on which a submersible barge may be set. This is especially true at locations off the mouth ft. deep while the soft, fluid or unconsolidated mud underlying the water may be several hundred feet deep. This mud often consists of from 60 to 90% solids and, has to serve at the base for drilling barges, which must be constructed with sufiicient bearing areas to rest on this However, even a barge of considerable weight does not sink into this mud far enough to be safe from currents or wave forces tending to move the barge. While at most locations on the Continental Shelf there generally no underwater currents, a storm of considerable duration will cause a constant movement of the water against a sunken barge tending to move it. Thus, in some cases astorm may cause the-.water toim'ove against asunken 2,938,353 Fatented May 31,1960

It is therefore a primary object of the present invention to provide a floatable drilling barge adapted to be submerged on an unconsolidated muddy bottom, said barge having sufiicient bearing areato support a drilling platform and associated drilling equipment at a predetermined height above the surface of the water. I

A further object of this invention is to provide a floatable drilling barge adapted to be submerged on a muddy 1 bottom in such a manner that the entire submerged pontoon ofthe barge sinks into the mud with the top deck of the. pontoon substantially level with the mud-water interface at the drillinglocation. 1

Another object of this inventionis to provide a floatable drilling barge adapted to be submerged in a manner such that .there is substantially no area on the ends of theisubmerged pontoon against which the force of the water currents may act. 7 It is a further object of this invention to provide a floatable-drilling barge having a submersible pontoon of a .design adaptedto cut into a muddy bottom to prevent lateral movement of the pontoon by underwater currents.

Another object ofthis invention is to provide a float- .able drilling barge having a submersible pontoon of a suitable design to allow it to sink into a muddy ocean bottom. in, such a manner as" to prevent any erosion of material from beneath the pontoon by currents or'the impact of waves 7 v These and other objects of the invention will be understood from the, following description taken with reference to. the drawing, .wherein:

Figurel is a view, of the present drilling barge, shown with its pontoon,-taken in cross-section, positionedin the mud below the surface of the water.

Figure 2 is ure-l. I Figure 3 is a bottom view of the barge of Figure 1, showing the drilling slot or bay through which drillin operations'are carried on. Figure 4 :is a cross-sectional view of the pontoon taken along the line 4--4'-of Figure2. i Figure 5 is a cross-sectional view of thepontoon, taken alongthe line 5-5; of Figure 2. Figures v6 and 7 are isometric projection views of other .rtypesof'pontoons of thepresent inventions 1 f- :3

.Figures 8, 8a and 9,-9a,. 9b are schematic views-illustrating barges of the present invention while floating and .while sunk at a selectedldrilling location.

0 Referring to Figure '1: of'thedrawing, the presentdrill- 'ing bargecomprises an operating platform 11 fixedly secured to and'supported by a plurality of vertical ,legs.or

a plan view of the, drillin grbar'ge columns 12 which are injturn afiixed to the topgof a of the Mississippi River where the water may be only 30 pontoon 13, which has substantially the same dimensions as the operating or drillingrplatform '11. The vertical hull at a constant speed of 1- knot o'r more during the duration ofthe storm, and to move 'a hull. In one storm,a submersible drilling barge, which was over '200 drawing, a pair ofsloping' longitudinal bl .1kheads,-.2 5

, merged position.

legs. 12 are of a length snfiicientvforthe drilling platform 11 to be, positioned .20 or 30 ftQabove the water line 14 while the pontoon '13 is sunkv flush with the mud level or line :15. The legs 12 may beconstructed ,as tubular columns, ll-beams or the like, having a diameteror size sufii'cient to give the necessary strength while being as small as possible to reduce the area against which current or wave forces might act when the barge is in its.sub-

Crossbracing members 17 may be employed to impart .added'rigidity to the structure. As shown-in'Figures .1..and;7 of the drawing, the pontoon 13 comprises a. top plate "20, endplateszl-and 22 .and side plates 23. and 24 with =the; bottom fi .th,e pantoon 'openl' As shown .in'Figures: .4 and S-Of; the

and 26 are provided and securely Welded in 'afiuidtight .manner to the top plate'320 and the side platesz23nand 1 24, respectively, to form longitudinal fluidtightz;,hallast tanks the-length of the barge along. eachusideithsreni.

the intersection of two side plates 23 and (Figure 6) of a pontoon ballast tank may have any suitable value, the controlling factor being the consistency of the mud bottom on which the pontoon 13 is to be positioned. Thus, in very soft bottoms, the downwardly pointing angle of the ballast tanks may have a value such as sixty degrees or more between the sides of the ballast tanks. On the other hand, when a barge of the present invention is to be sunk on an ocean floor that is more firm, the downwardly pointed angle of the ballast tanks may be as little as or less, in order to permit the tanks to be thin and sharp enough to be forced completely into the soft bottoms so that the top plate 20 of the pontoon rests upon the bottom and supports the weight of the drilling platform positioned thereabove.

The base pontoon 13 of the present invention may be employed also on barges as shown in Figures 8 and 9 having operating platforms 11 that normally carried on the pontoons 13 when the barge is floated into position to increase the stability of the barge during movement to the drilling location. On arrival at the location, the platform 11 is raised up the legs 12 of the barge by suitable winches, hoists, air-jacks, etc., in a manner Well known to the art until the platform is at the desired height.

In the barge shown in Figure 9, the platform 11a is also a pontoon member adapted to aid in floating the barge when it is desired to carry loads of heavy equipment (not shown) on the operating platform when the barge is being moved. On arrival at the drilling location the base pontoon 13 is evacuated and sunk in the mud (Fig. 9a) in a manner previously described. Subsequently the platform 11a is jacked or hoisted on the legs 12 to a desired height above the water level (Fig. 9b).

In addition to the downwardly pointing ballast tanks sinking in a soft or muddy sea bottoms, the vertical plate members and 42 (Figs. 1 and 3) secured to the bottom of the barge and extending downwardly therefrom into the mud also tend to prevent horizontal movement of the barge in mud due to ocean currents. Similar vertical plate members 40 and 42, either fixed or movable, could be secured to the bottom or sides of other types of pontoons, submersible drilling barges or platforms well known to the art to prevent their movement on a muddy bottom. If necessary the vertical plate members 40 and 42 of the present pontoon 13 could be made longer so as to extend deeper into the mud to give greater holding power.

Instead of employing a single large submersible pontoon 13 as illustrated in Figure 1 of the drawing, it may be more desirable in certain instances, such as on soft uneven ocean floors, to employ several small pontoons of the present design to support one or more opera-ting platforms, or to use a single large sectional pontoon to conform to uneven bottom conditions. The pontoon of the present barge is also found to be of considerable use by itself when used as a breakwater unit for other types of drilling barges or platforms positioned in offshore locations. As a breakwater unit the pontoon may be constructed 40 or more feet high, without a drilling slot in one end, and is sunk in the bottom only a suflicient depth to prevent its being moved by wave action.

I claim as my invention:

1. A drilling barge for drilling wells on ofishore locations in bodies of water covering soft muddy bottoms, said barge comprising a floatable pontoon member adapted to be sunk to form a base for the barge on the muddy hottom, vertical leg members secured to the pontoon memher and extending upwardly above the surface of the water when the pontoon member is positioned in the mud, an operating platform carried by said leg members, said pontoon member and said operating platform each being provided with an opening of a size to permit well drilling tools to pass therethrough, said openings being in vertical alignment with each other, said pontoon member comprising rigid topplate means having at least two longitudinal ballast tanks affixed to the underside in spaced relationship and along two opposite edges thereof, said ballast tanks having a height substantially greater than the thickness of said top plate means and being triangular in cross-section with one side of the triangle being formed by the top plate means and one angle of the triangle pointing downwardly, said triangular ballast tanks having a buoyancy suflicient to float the barge, and means for flooding said ballast tanks, thereby causing the downwardly-pointed ballast tanks to penetrate and become submerged in the muddy ocean bottom until the top plate means of the pontoon member substantially rests level with and on top of the mud to support the barge during drilling operations.

2. A drilling barge for drilling wells on offshore locations in bodies of water covering soft muddy bottoms, said barge comprising a floatable pontoon member adapted to be sunk to form a base for the barge on the muddy bottom, vertical leg members secured to the pontoon mem her and extending upwardly above the surface of the water when the pontoon member is positioned in the mud, an operating platform carried by said leg members, said pontoon member and said operating platform each being provided with an opening of a size to permit well drilling tools to pass therethrough, said openings being in vertical alignment with each other, said pontoon member comprising a rigid top plate member having at least two longitudinal, triangular in cross-section ballast tanks aflixed to the underside in spaced relationship and along the longitudinal edges thereof, said triangle being formed by the top plate member and one angle of the triangle pointing downwardly, said triangular ballast tanks having a buoyancy suflicient to float the barge, vertically-positioned transverse plate members extending between said ballast tanks and being secured to said tanks and to said rigid top plate member to form a plurality of open-bottom cells adapted to be filled with air, and means for flooding said ballast tanks and cells, thereby causing the downwardly-pointed ballast tanks to penetrate and become submerged in the muddy ocean bottom until the top plate member of the pontoon member substantially rests level with and on top of the mud to support the barge during drilling operations.

References Cited in the file of this patent UNITED STATES PATENTS 720,997 Becker Feb. 17, 1903 1,971,046 Moran Aug. 21, 1934 2,589,146 Samuelson Mar. 11, 1952 2,591,599 Parks Apr. 1, 1952 2,622,404 Rice Dec. 23, 1952 2,677,935 Schaufele May 11, 1954 2,699,042 Hayward Jan. 11, 1955 FOREIGN PATENTS 978,769 France Nov. 29, 1950

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