US3666395A - Offshore gas flare apparatus - Google Patents

Abstract

APPARATUS FOR CONDUCTING WASTE GAS PRODUCED FROM AN OFFSHORE WELL EXTENDING INTO THE FLOOR OF A BODY OF WATER TO A REMOTE LOCATION. A PLATFORMS STRUCTURE RESTS ON THE WATER FLOOR AND INCLUDES A GAS LINE IN SELECTIVE FLUID COMMUNICATION WITH THE WELL, THE GAS LINE LEADING TO THE REMOTE LOCATION. A GAS FLARE PIPE IS BUOYANTLY SUPPORTED IN A VERTICAL POSITION AT THE REMOTES LOCATION AND IS FLUID COMMUNICATION WITH THE GAS LINE. THE SUPPORT FOR THE PIPE INCLUDES A RELATIVELY SHORT SPAR BUOY ANCHORED TO THE FLOOR OF THE BODY OF WATER THROUGH AN ELONGATED FLEXIBLE CABLE PIVOTALLY ATTACHED THERETO. IN THIS MANNER, WASTE GAS FROM THE WELL MAY BE BURNED OFF (OR VENTED TO THE ATMOSPHERE) WHILE THE SUPPORT ALLOWS FOR MOVEMENT OF THE GAS FLARE PIPE WITH WATER MOTION.

Description

y 0, 1972 J. w. KUBASTA 3,666,395

OFFSHORE GAS FLARE APPARATUS Filed July 29, L970 2 Sheets-Sheet l I I T; f

WH 27 25 3O INVENTOR. JAMES W. KUBAS TA A WMM ATTORNEY May 30, 1972 J. w. KUBASTA OFFSHORE GAS FLARE APPARATUS 2 Sheets-Sheet Filed July 29, L970 FIG. 3

v INVENTOR. JAMES W. KUBASTA ATTORNEY United States Patent O 3,666,395 OFFSHORE GAS FLARE APPARATUS James W. Kubasta, Metairie, La., assignor to Shell Oil Company, New York, N.Y. Filed July 29, 1970, Ser. No. 59,247 Int. Cl. F23c 9/00 U.S. Cl. 431-202 Claims ABSTRACT OF THE DISCLOSURE Apparatus for conducting waste gas produced from an offshore well extending into the floor of a body of water to a remote location. A platform structure rests on the water floor and includes a gas line in selective fluid communication with the well, the gas line leading to the remote location. A gas flare pipe is buoyantly supported in a vertical position at the remote location and is in fluid communication with the gas line. The support for the pipe includes a relatively short spar buoy anchored to the floor of the body of water through an elongated flexible cable pivotally attached thereto. In this manner, waste gas from the well may be burned off (or vented to the atmosphere) while the support allows for movement of the gas flare pipe with water motion.

BACKGROUND OF THE INVENTION Field of the invention The invention relates to offshore gas flares; and, more particularly, to apparatus for conducting waste gas produced from an oflshore well to a remote location where the waste gas is burned ofl.

Description of the prior art In offshore drilling and/or producing operation, it is necessary to burn waste gas from wells, and it is desirable to position the resulting flare at some distance away from the drilling platform. This involves providing a pipe for conducting the gas from the well to a point above the surface of the water, which may be 100 feet deep, for example.

SUMMARY OF THE INVENTION It is an object of the invention to provide an offshore gas flare line comprising a pipe extending from a point below the surface of the water to a point above it and means for anchoring the pipe and for supporting it in a substantially vertical position.

Another object of the invention is to provide an offshore gas flare line comprising a pipe extending from a point below the surface of the water to a point above it and means capable of yieldably supporting the pipe in a substantially vertical position whereby the pipe may be deflected away from its upright or vertical position, and may assume an inclined position, upon being struck by a passing boat or other object, and is capable of righting itself quickly after being so deflected.

Another object of the invention is to provide an offshore gas flare line, and an anchor and a float therefor, which are resistant to the action of wind and waves.

These and other objects are preferably accomplished by providing a gas line in selective fluid communication with an underwater well, the gas line leading to a remote location. A gas flare pipe is buoyantly supported in a vertical 3,666,395 Patented May 30, 1972 BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a vertical sectional view of preferred apparatus for carrying out my invention; and

:FIGS. 2 through 4 are vertical sectional views of the apparatus of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 of the drawing, a portion of an olfshore platform structure 10 is shown resting on or fixed to the floor 11 of a bottom of water, such as an ocean 12. Structure 10 is supported by a plurality of legs, only one of the legs 13 being shown in FIG. 1. Suitable bracing 14 extends between the platform structure legs as is Well known in the art. However, although a platform structure 10 is shown permanently anchored in place on floor 11, the techniques of my invention are applicable to any offshore structure which may be temporarily anchored in place, such as a floating platform (not shown) held in place by selectively releasable anchors or the like (also not shown). In all cases, however, the platform structure is in selective fluid communication with an underwater wellhead, as for example, wellhead structure 15 of FIG. 1 which communicates with a hydrocarbon-producing well 16 extending into the ocean floor 11. A pipe string 17 or the like is in fluid communication with wellhead structure 15 and extends to a working platform 18 on structure 15.

Preferably, a railing 19 extends longitudinally along one of the legs of platform structure 15, such as leg 13in FIG. 1. A gas pipe 20 is attached to structure 15 along a portion of the railing 19. In other words, pipe 20 has a first riser portion 21 extending from working platform 18 generally parallel to leg 13 and fixedly Secured thereto by means of a plurality of clamps 22 on either leg 13 or railing 19 or both as shown. The terminal portion 23 of pipe 20 at working platform 18 is adapted to be selectively secured to and in fluid communication with pipe string 17, as for example, through a connecting pipe portion 24. Obviously, portion 24 may be adapted to be disconnected from terminal portion 23 of pipe 20 by any suitable means and suitable valves and control means therefore may also be provided. Further, other types of arrangements may be used for conveying waste gas from well 16 and pipe string 21 and into gas pipe 20.

A second portion 25 of gas pipe 20 extends outwardly from and generally horizontal to platform 10 to a location remote from structure 10. The second portion 25 is generally flexible and comprised of a plurality of hose sections. In such a manner, waste gas may be conducted from well 16 some distance away prior to burning it. Riser portion 21 may be selectively disconnected from second portion 25 by means of a flange-type releasable connector 26 located at the junction of riser portion 21 and second portion 25 adjacent railing 19. In like manner, a plurality of similar connectors 26 may be disposed along the second portion 25 of gas line 20 for selectively adding on and subtracting sections thereof to thus vary the overall length of portion 25.

A plurality of hose weights 27 are also disposed along portion 25 of gas line 20 for providing a slight negative buoyancy to line 20. Weights 27 may be added or removed, as desired, to so vary the buoyancy of second portion of line 20. As can be seen in FIG. 1, second portion 25 of gas line 20 extends from platform structure at some point below the mean water line 58 and at some point substantially above the floor 11 of ocean 12.

A gas flare pipe supporting structure 28 is disposed at the desired distance from platform structure 10. Structure 28 includes a buoyant spar buoy 29 (see FIG. 2) coupled to gas line by suitable connecting means, such as connector 30 similar to connectors 26 (see also FIG. 1). Spar buoy 29 includes a generally vertical, tubular body member 31 evacuated or filled with a suitable buoyant material, such as polyurethane foam, as for example, four pounds per cubic feet in density. A similar buoyant material-filled body member 32 may be secured to body member 31 generally perpendicular thereto and on the upper portion thereof for stabilizing the spar buoy 29 and providing additional buoyancy. Suitable braces 33 may extend between members 31 and 32 and be secured thereto for reinforcing the members.

Gas line 20 preferably includes a second riser portion 34 extending generally horizontally from connector 30, then upwardly through body member 31 as shown in dotted lines in FIG. 2. At its upper end, riser portion 34 is preferably detachably secured, as through a releasable connector 35, to a gas flare pipe 36. A bracket 37 having a pin 38 thereon, is mounted on the lower end of spar buoy 29. A wireline 39 is secured to bracket 37 as will be discussed hereinbelow.

Thus, referring now to FIG. 3, wireline 39 includes a sleeve 40 at its extremity which carries a socket portion 41 for passing over pin 38 with pivotal movement therebetween. Pin 38 further includes a suitable aperture 42 therein for receiving a securing pin 43 therethrough for firmly and pivotally securing wireline 39 to spar buoy 29. Spar buoy 29 further includes a plurality of brackets, as for example, bracket 44 (FIG. 3) and bracket 45 (FIG. 2) secured to the outer surface thereof. Thus, as seen in FIGS. 1 and 2, the upper end of wire line 39 is attached to spar buoy 29 by bracket 45, passes down through an aperture 46 in body member 32, then through a conventional wireline clip 47 mounted on bracket 44 (see also FIG. 3).

Referring now to FIG. 4, wireline 39 next passes around the sheave 48 of a toggle block 49 pivotally connected through pin 50 to an anchor connecting pad-eye 51.

.Any suitable anchoring connecting means may be used to pivotally connect pad-eye 51 to Weight 52. Further, any suitable weight may be used. Thus, weight 52 ma have a pad-eye 53 at its upper end having at least a pair of upwardly extending flanges 54 having suitable apertures extending therethrough. The lower portion of pad-eye 51 preferably forms a tubular opening 55 therein. A connecting pin 56 preferably extends through both opening 55 and the apertures in flanges 54 in such a manner that pad-eye 51 is adapted to rotate about pin 56 and thus about pad-eye 53. Finally, connecting pin 56 preferably includes movement limiting means in the form of stops 57 for limiting the lateral movement of pin 56.

Referring once again to FIG. 1, it can be seen that the overall length of wireline 39 between the lower end of spar buoy 29 and weight 52 may be relatively great compared to the overall length of spar buoy 29. Spar buoy 29 may include means thereon for varying the buoyancy thereof, such as, for example, apertures therein (not shown) for selectively removing and adding portions of the buoyant material. As discussed hereinabove, the second portion of gas pipe 20 preferably extends from platform structure 10 to a distance below the mean water line 58 of the body of water 12. Further, the gas flare pipe 36 also extends above the mean water line 58. A burner tip 59 is provided on gas flare pipe 36 and suitable means,

such as a ladder (not shown) may extend from body member 32 on spar buoy 29 to the burner tip 59 for lighting the same.

In operation, the first riser portion 21 of gas line 20 is connected to pipe portion 24, thus providing tfluid communication with pipe string 17. The second portion 25 of gas line 20 is connected, at one end through connector 26, to riser portion 21 and at the other end, through connector 30, to the second riser portion 34 passing through spar buoy 2'9. Spar buoy 29 is anchored to weight 52 through wireline 39 and the overall length of wireline 39 is adjusted so as to maintain spar buoy 29 at its desired location in ocean 12 with respect to mean water line 58. The buoyancy of spar buoy 29 is set so as to maintain gas flare pipe 36, at the upper end thereof, above the mean water line 58 and in a substantially vertical position in ocean 12. Weights 27 may then be added along the second portion 25' of gas line 20 so as to vary the negative buoyancy thereof. Finally, burner tip 59 is ignited and waste gases from well 16 are burned off to the atmosphere.

-In this manner, the gas flare pipe support 28 described hereinabove permits the gas flare pipe 36 to be deflected away from its upright substantially vertical position and immediately right itself. The slight negative buoyancy imparted to gas line 20 through weights 26 maintains the hose 25 below the anticipated draft of passing boats. The wireline 39 gives the flexibility to the spar buoy 29 necessary to permit the structure 28 to flex when subjected to water action, external forces, etc.

I claim as my invention:

1. Apparatus for conducting waste gas produced from an offshore well extending into the floor of a body of water to a remote location preparatory to burning ofl. said waste gas, said apparatus comprising:

a platform structure associated with said well;

a first riser portion extending down along said platform structure, said first riser being fixedly secured to said platform structure;

a horizontal portion extending generally outwardly from said platform structure to a remote location, said horizontal portion being fiangibl'y connected at one end to said first riser, said horizontal portion including at least one flexible hose section;

a second riser portion fiangibly connected at its lower end to said horizontal portion, said second riser portion extending from a generally horizontal position to a substantially vertical position at its upper end;

a gas flare pipe having a burner tip thereon, said gas flare pipe being detachably connected to said second riser portion at its uper end;

buoyancy means surrounding said second riser portion, said buoyancy means being suitably connected to said second riser portion thereby maintaining said gas flare pipe in a substantially vertical position in said body of water with respect to the floor thereof;

a Weight member disposed on the floor of said body of water; and

an elongated flexible cable means, one end of said cable being suitably connected to the outer surface of said buoyancy means, said cable passing around a sheave pivotally connected to said weight member and terminating at a pivotal connection disposed on the lower end of said buoyancy means whereby the overall length of said elongated flexible cable means is adjusted so as to maintain the buoyancy means in a substantially vertical position at a desired location in a body of water.

2. The apparatus of claim 1 wherein said buoyancy means comprises a first tubular body member; and

a second body member generally perpendicular to said first tubular member, said second body member being secured to said first tubular body member thereby stabilizing said first tubular body member.

'3. The buoyancy means of claim 2 wherein said first tubular member is evacuated thereby providing additional buoyancy.

4. The buoyancy means of claim 2 wherein said first tubular member is filled with a buoyant material.

5. The apparatus of claim 1 wherein said second portion further includes a plurality of removable hose weights thereby varying the buoyancy of said horizontal portion to maintain said horizontal portion at some point substantially above the floor of said body of water.

References Cited UNITED STATES PATENTS EDWARD G. FAVORS, Primary Examiner US. Cl. X.R.

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