US3461828A - Floating drilling platform - Google Patents

Description

969- w. J. BIELSTEIN 3,461,828 FLOATING DRILLVING PLATFORM Filed April 15. 1968 5 sheet-sheet 1 Aug. 19, 1969 w. J. BIELSTEiN FLOATING v DRILLING PLATFORM 5 Sheets-Sheet 2 Filed April 15, 1968 F'IG..3.

INVENTOR. WALTER J. BIELSTEIN,

FIG. 6.

T T V NEY Aug. 19, 1969 W. J. BlELSTEIN FLOATING DRILLING PLATFORM Filed April 15, 1968 5 Sheds-Sheet 5 INVENTOR. WALTER J. BIELSTEIN FIG. 8.

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ATTOR Y- United States Patent O 3,461,828 FLOATING DRILLING PLATFORM Walter J. Bielstein, Houston, Tex., assignor to Esso Production Research Company Filed Apr. 15, 1968, Ser. No. 721,510 Int. Cl. B63b 35/44, 35/00 U.S. Cl. 114-5 15 Claims ABSTRACT OF THE DISCLOSURE A floating drilling platform is provided by a vessel which is moored for 360 rotation about its axis by rotatably and peripherally anchoring the vessel by a plurality of at least two anchors flexibly, rotatably and peripherally attached to the vessel, the vessel being adapted to be supported above wave action on an air cushion and maintained in a selected location with respect to water bottom during drilling operations.

BACKGROUND OF THE INVENTION Field of the invention The present invention is directed to a method for mooring a vessel in a body of water for conducting drilling operations. More specifically, the invention is concerned with apparatus for maintaining a floating vessel at a selected location for conducting drilling operations. In its more specific aspects, the invention is concerned with apparatus and method for conducting drilling operations embodying a floating vessel supported by an air cushion.

Description of the prior art Heretofore, it has been known to provide vessels sometimes called ground eifect vessels which are movable over water or land supported by an air cushion under the vessel. It is also known to move such vessels over water above wave action. Such vessels may have flexible skirts which are provided with vertical slits. However, it has not been known to utilize such vessels in drilling operations wherein the vessel may be maintained above wave action and, therefore, the deck maintained substantially horizontal. In accordance with the present invention, a vessel and a mooring system are provided which will permit 360 rotation of the vessel and the vessel is maintained substantially above wave action.

Specific prior art considered with respect to this invention include the following list of U.S. Patents: 3,047,080, 3,055,446, 3,07 8,938, 3,316,871.

SUMMARY OF THE INVENTION The present invention may be briefly described as a method for mooring a vessel in a body of water for 360 rotation about its axis in which the vessel is rotatably and peripherally anchored by a plurality of anchors flexibly, rotatably and peripherally attached to the vessel thereby maintaining the vessel at a fixed location relative to water bottom. The vessel is maintained such that its deck is substantially parallel to the horizon. In other words, the deck is maintained substantially horizontally. This is accomplished by supporting the vessel on an air cushion substantially above any waves. The present invention also embodies conducting drilling operations from the vessel.

The invention may also be briefly described as embodying apparatus for conducting drilling operations in a body of Water in which a vessel adapted to float in the body of water is provided. The vessel is provided with at least a chamber formed under the vessel which is open on its bottom for confining a gasiform medium under pressure in the chamber between the vessel hull and the water surface. Means for introducing a gasiform medium under ice pressure into the chamber is provided to maintain the vessel above water. A circular deck is mounted on the vessel and a peripheral rail means is arranged on the circular deck to which a plurality of at least two anchor means is flexibly attached for rotation of the vessel about its axis. The vessel and deck are provided with an open well through which drilling operations may be conducted and drilling means are located on the deck, preferably above the well, but may be located adjacent one side of the deck and overhanging the water. In short, the well may not be necessary. The deck may be suitably supported adjacent its periphery by outriggers which are each provided with a chamber for confining a gasiform medium under pressure and with means for supplying gasiform medium under pressure to each of the outrigger chambers. The anchor means are suitably attached to a wheeled carriage means, slidable means, or the like riding on the rail means for rotation of the vessel 360 about its axis.

BRIEF DESCRIPTION OF THE DRAWING The present invention will be further illustrated by reference to the drawing in which:

FIG. 1 is a top view of the deck of the vessel showing the anchor lines with the outriggers and vessel indicated by dotted lines;

FIG. 2 is a sectional view taken along the lines 2-2 of FIG. 1;

FIG. 3 is a front elevational view showing one of the outriggers in section;

FIG. 4 illustrates the anchor line connected to a wheeled carriage riding on the mono-rail;

FIG. 5 is a view of FIG. 4 taken along lines 5-5;

FIG. 6 is a top view similar to FIG. 1 showing the rotation of the vessel in dotted lines in accordance with the wind direction; and

FIGS. 7 and 8 are fragmentary sectional views illustrating a modification of the device of the preceding figures.

DESCRIPTION OF THE PREFERRED MODES AND EMBODIMENTS WITH REFERENCE TO THE DRAWING Referring now to the drawing, in which identical numerals designate identical parts, numeral 11 designates a circular deck spaced above and connected to a conventionally shaped hulled vessel 12. Arranged on the periphery of the deck :11 is a circular mono-rail 13 in which is attached anchor lines 14 which are shown as four in number, but which may be any number but at least two.

The deck 11 is provided with a drilling derrick 15 including drilling means 16 and 17 indicated by the rectangles.

The deck 11 is suitably supported on the vessel '12 as shown more clearly in FIG. 2 by supporting means 18 which are suitably cross-braced, the supporting means 18 being attached to the second deck 19. The deck 19 may be provided with tanks 20 and other equipment associated with drilling operations, such as 21 and 22. The hull of the vessel 12 may be provided with compartments 23 which may contain machinery 24 and 25 and a pressure control means '26 and other unidentified equipment 27. The vessel 12 is also provided with an open well 28 above which the derrick 15 is located. This open well also extends through the deck 11. The vessel :12 is preferably formed to provide an air chamber 29, which communicates with the pressure control means 26 by conduit or pipe 30, through which air or other gasiform medium is introduced into chamber 29. The chamber 29 is suitably cross-braced and reinforced by structural members 31.

It will be noted that the vessel 12 is arranged in a body of water 32 having a water surface 33 and spaced from water bottom 34 which may be any distance from water surface 33 and may range from 50 feet or less to several thousand feet or more.

Referring now to FIG. 3, the vessel 12 is shown with outrigger pontoons 35 which are connected to the deck 11 by structural members 36 and 37. It is to be noted that the outrigger pontoons 35 provide a chamber 38 to which air hoses or pipe conduits 39 extend. The air hoses or pipe conduits are suitably connected to pressure control means 2-5 for adjusting the pressure in the chambers 33 of the outrigger pontoons 35.

Referring now to FIGS. 4 and 5, it will be noted that the mono-rail 13 has a wheeled carriage 49 riding thereon to which is connected the flexible anchor lines 14.

Referring to FIG. 6, it will be noted that the vessel 12 is anchored by four anchors 41 connected by flexible lines 14 to four carriages 4t) riding in and on mono-rail 13. Thus, with the top of the drawing indicating a northerly direction, the vessel 12 will face into the wind with the anchor lines 14 and anchors 41 remaining stationary. With the right-hand side of the drawing indicating an easterly direction, the vessel 12 will head into the wind and again the platform 11 will be maintained in the same location relative to water bottom 34.

Referring now to FIGS. 7 and 8, there is illustrated a wheeled carriage 50, which like carriage 40, is adapted to ride or roll in mono-rail 13. Carriage 56 is provided with an anchor line clamp 51 which is adapted to releasably clamp line 14a which extends through it. The anchor line 14a passes over pulleys 52 and 53 and is wound on drum reel 54 which is powered by motor means 540. Rollers 55 and 56 engage mono-rail 13 and take the full load of the anchor line 14a through clamp 51. Rollers 57 ride in circular track 58 which is concentric to circular mono-rail 13. Additional rollers 59 mounted in carriage t} engage and roll on the underside of platform 11.

The motor powered reel drum S4 is used for taking in or paying out anchor line and also to adjust tension on the anchor line when needed. The full load of the anchor line tension, however, is exerted against the clamp 51 and the mono-rail 13.

When it is desired to take-up or slack-off on line 145:, the reel is set by the motor means, the clamp released, the tension adjusted by the motor means and the line again clamped, whereby no constant tension is exerted on the drum reel. Each of the anchor lines 14 are attached to the platform 11 in the same manner. It is understood that although lines 14a are shown as cables they may also be chains.

When wave action becomes such that the vessel 11 is in danger of heaving and yawing, air or gas pressure is introduced into the chamber 29 and to the chambers 38 of the outrigger pontoons 35. As shown in FIG. 1, the outrigger pontoons 35 may suitably be boat-shaped as shown, but may be of any shape. Likewise, the vessel 12 may be of any configuration.

The height that the vessel of the present invention rises in the water may be adjusted by the size of and the pressure in the air space in the chamber 29 and chambers 38. Air space may be maintained by maintaining a constant pressure such as with a turbine compressor. It is contemplated that the hull bottom of vessel 12 may be surrounded or formed by a flexible skirt such as natural or synthetic rubber. This skirt may be suitably provided with vertical slits for increased flexibility. This air space adsorbs essentially all wave action and a drilling vessel does not pitch and roll in high seas. The mono-rail control system provides for facing the ship hull into the wind at all times. Thus, drilling operations may be carried on without interruption even during high seas.

The present invention is, therefore, quite advantageous and useful.

If a mooring system is not used with the present invention, the invention is also of utility in that it may be anchored by other means and maintained above wave action during drilling operation; for example, the vessel 12 may be of the seadrome type and anchored with pontoons anchored directly to sea bottom, but open on the lower end to provide an air cushion.

The nature and objects of the present invention having been fully described and illustrated and the best mode and embodiments contemplated set forth what I wish to claim as new and useful and secure by Letters Patent is:

1. A method for mooring a vessel having a platform spaced vertically above the decks of said vessel in a body of water for 360 rotation about its axis which comprises:

rotatably and peripherally anchoring said vessel by a plurality of at least two anchors flexibly, rotatably and peripherally attached to and on said platform above said vessel; and

maintaining said anchored vessel at a fixed location relative to water bottom.

2. A method in accordance with claim 1 in which said anchored vessel is maintained at said fixed location such that its decks are substantially horizontal.

3. A method in accordance with claim 2 in which the decks of said vessel are maintained substantially horizontal by supporting said vessel on an air cushion above any waves.

4. A method in accordance with claim 1 in which a well drilling operation is conducted from said vessel.

5. A method in accordance with claim 1 in which:

(a) the platform of the anchored vessel is circular;

(b) the decks of the anchored vessel are maintained substantially horizontal by supporting said vessel on an air cushion above any Waves.

6. A method in accordance with claim 5 in which a drilling operation is conducted from said vessel.

7. Apparatus for conducting drilling operations in a body of water which comprises:

a vessel adapted to float in said body of water;

a chamber formed under said vessel and open on its bottom for confining a gasiform medium under pressure in said chamber;

means for introducing gasiform medium under pressure into said chamber;

a circular deck mounted on said vessel;

a peripheral rail means on said circular deck; and

a plurality of at least two anchor means flexibly attached to said rail means for rotation of said vessel about its axis.

8. Apparatus in accordance with claim 7 in which the vessel and deck are provided with an open well through which drilling operations may be conducted.

9. Apparatus in accordance with claim 8 in which drilling means are located on said deck above said well.

10. Apparatus in accordance with claim 8 in which drilling means are located on said deck,

11. Apparatus in accordance with claim 8 in which the deck is supported adjacent its periphery by outriggers.

12. Apparatus in accordance with claim 11 in which the Outriggers are each provided with a chamber for confining a gasiform medium under pressure and in which means are provided for supplying gasiform medium under pressure to said outrigger chambers.

13. Apparatus in accordance with claim 8 in which:

(a) the vessel and deck are provided with an open well for conducting drilling operation;

(b) drilling means are located on said deck above said well;

(c) the deck is supported adjacent its periphery by Outriggers; and

(d) the Outriggers are each provided with a chamber for confining a gasiform medium under pressure and in which means are provided for supplying gasiform medium under pressure to said outrigger chambers.

14. Apparatus in accordance with claim 13 in which the anchor means are flexibly attached to a wheeled carriage riding on said rail means.

5 6 15. Apparatus in accordance with claim 7 in which 3,279,404 10/1966 Richardson. the anchor means are flexibly attached to a wheeled car- 3,285,213 11/ 1966 Whittle. riage riding on said rail means.

TRYGVE M. BLDC, Primary Examiner References Cited 5 US Cl XR UNITED STATES PATENTS 61 46'5;

2,771,617 11/1956 BrackX.

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