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Publication numberUS3413946 A
Publication typeGrant
Publication dateDec 3, 1968
Filing dateAug 31, 1966
Priority dateAug 31, 1966
Publication numberUS 3413946 A, US 3413946A, US-A-3413946, US3413946 A, US3413946A
InventorsSchultz Hans Udo Von
Original AssigneeMobil Oil Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Spar buoy vessel
US 3413946 A
Abstract  available in
Images(2)
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Claims  available in
Description  (OCR text may contain errors)

Dec. 3, 1968 H. u. VON SCHULTZ 3,413,946

SPAR BUOY VESS EL Filed Aug. 31, 1966 2 Sheets-Sheet 1 68 mvsm'on A'ITORNEY Dec. 3, 1968 H. u. VON SCHULTZ 3,413,946

SPAR BUOY VESSEL Filed Aug. 31, 1966 2 Sheets-Sheet 2 INVENTOR A'FI'ORNEY HANS UDO VON SCHULTZ United States Patent 3,413,946 SPAR BUOY VESSEL Hans Udo von Schultz, Fort Worth, Tex., assignor to Mobil Oil Corporation, a corporation of New York Filed Aug. 31, 1966, Ser. No. 576,338 31 Claims. (Cl. 114-.5)

ABSTRACT OF THE DISCLOSURE This specification discloses a versatile floating vessel suitable for the exploitation of subaqueous fluid mineral deposits. The vessel includes a shipshaped platform and a spar buoy hull connected so that the vessel can be transported across a body of water with the portions thereof aligned to form a composite shipshaped vessel. The vessel is arranged at a marine site with the spar buoy hull depending vertically into the water and supporting the platform above the surface. The platform maintains the same orientation in both arrangements. With 'a drilling rig mounted on a deck of the platform, a drill string can be guided into a borehole extending into the formations underlying the marine bottom through a passage extending through the spar buoy hull of the vessel. The spar buoy hull can be utilized as a portion of a marine conductor pipe. The vessel can be dynamically positioned, the positioning motors being controlled in conjunction with transponders fixed on the marine bottom around the borehole, or means for detecting the deviation of the drill string from the axis of the passage through the spar buoy hull in which it is suspended.

This invention relates to a versatile marine structure for providing a stable above-surface platform at a marine site. More particularly, the invention relates to a spar buoy drilling vessel that can be transported across a body of water at relatively high speeds.

When drilling in deep water, especially depths beyond that which may now be reached with a bottom-supported template or a jack-up platform, the floating drilling vessel has found acceptability. Of the various configurations of floating drilling vessels, the spar buoy type is theoretically the most stable under many conditions and therefore would be desirable, particularly in areas noted for frequent storms. A spar buoy type of drilling vessel, however, would be an extremely unwieldy structure and, as of this date, none have been built. In fact, the only spar buoy type vessel that is known to exist at this time is an experimental flip-ship (Flip Floating Instrument Platform, Journal of Acoustical Society of America, vol. 35, No. 10, October 1963) being utilized for oceanographic work. The flip-ship has overcome one of the major drawbacks of the spar buoy type of marine vessel by its unique construction which allows it to be reoriented from a position in which it can be transported, horizontally On the surface of a body of water, to a stable working position at a marine site, depending vertically into the body of water. However, while such a vessel may be very useful as a research instrument, it would not be accept-able in the oil and gas industry, as a drilling vessel, due to the reorientation of the entire vessel including the working decks.

Exploration and production efforts in the oil and/or gas industry have been extended to remote areas throughout the world subsequent to the leasing of the more accessible and desirable acreages. In the recent drive to discover and tap hydrocarbon deposits beneath the continental shelves and even the more recent developing ability to extend the exploitable regions to the deeper waters of the continental slopes (over 600 feet), leases have been obtained for such remote offshore areas as the West Coast of Africa and the coasts of Australia. In some of the Patented Dec. 3, 1968 largely untested areas, leases may be obtained for only one or two hundred dollars an acre, resulting in very large tracts. To make the use of a spar buoy type of drilling vessel practical, it must be possible to transport the vessel quickly from its home port to the above-discussed remote areas, at which it will be located during drilling operations and it must be furthermore possible to quickly and easily move the vessel from one exploratory drilling site to another across a large tract. Even a conventional drilling platform of the jack-11p or wave transparent types, under tow from the United States to the remote foreign site and back, expends ninety to two hundred days at the usual towing speed of two to three knots. The cost of transporting so immense a structure across the span of an ocean includes towing charges of $1,000 to $1,500 per day, plus towing insurance of $400 to $500 per day in addition to a per diem rate. (The quoted charges are merely representative and are only included to permit the reader to obtain an appreciation of the magnitude of the costs involved in the operation of a marine drilling veS- sel.)

The optimum drilling vessel, when considering only the speed at which it can move across a span of water, is one of shipshaped design. Examples of such vessels are the Glomar and the Torry, that have been used extensively for drilling in the coastal waters of the United States. These vessels are similar to an ordinary ocean-going freighter with the exception of a moonpool or central vertical well which is formed through the hull of the vessel directly below the drilling rig. The problem with a shipshaped drilling vessel is that it is greatly affected by any surface winds and wave action. Drilling operations must be suspended during rough weather and the vessel must be completely removed from the drilling site during storms. While heave, pitch, roll, and the other possible motions occurring on a vessel at sea may be compensated for, to some degree, during the drilling operation, there is an acceptable level of motion above which the drilling or workover operations must be terminated. For example, with shipshaped vessels in the Gulf of Mexico in 1964, over five percent down time was experienced by contractors due to weather conditions alone.

A spar buoy type of drilling vessel, however, can remain at a site and continue drilling through all but the most violent storms. Due to the depth at which the spar hull depends beneath the waters surface, the deck motions resulting from surface agitation are greatly subdued to the point at which they are no longer a major problem. However, this type of drilling vessel with its supporting spar buoy hull, depending deep into the water, causes a tremendous hydrodynamic drag during towing. Most of the suggestions to date, on using a spar buoy type of drilling vessel, have considered using a prefabricated structure which is assembled at the site and then must be disassembled and removed by barge to the next drilling site. Such an undertaking is not feasible in remote areas where facilities for such operations are extremely limited.

Accordingly, it is an aspect of the present invention to provide a stable marine platform structure capable of drilling and maintaining subaqueous wells in deep water.

It is another aspect of the present invention to provide a stable marine platform or structure capable of being towed, or propelling itself, long distances at speeds substantially equal to those of a shipshaped vessel.

Other aspects and advantages of the present invention will be readily apparent from the following description, when taken in conjunction with the accompanying drawings which illustrate useful embodiments in accordance with this invention:

FIGURE 1 is an elevational view of the marine drilling vessel of the present invention showing the spar buoy hull thereof floating in a horizontal position on the surface of the body of water behind the shipshaped hull of a working platform, when the marine drilling vessel is under tow or being self-propelled to a remote site;

FIGURE 2 is an elevational view, partially in section, of the marine drilling vessel of FIGURE 1, with the spar buoy hull thereof floating vertically in the body of water to support the working platform above the surface during a drilling or workover operation, and illustrating means for determining when the floating marine drilling vessel has drifted away from a position directly above a subaqueous borehole;

FIGURE 3 is a cross-sectional view taken along line 33 of FIGURE 2 illustrating the means for adjusting the orientation of the spar buoy hull with respect to the above-surface platform;

FIGURE 4 is a view taken through line 4-4 FIG- URE 2 illustrating, in schematic form, a photoelectric position indicating system;

FIGURE 5 is an illustrative view of the face of a receiving instrument, partially broken away, that would be mounted on the bridge or in the control room on the marine drilling vessel for visually showing an off-center position of the drill string as recorded by the photoelectric position indicating system of FIGURE 4;

FIGURE 6 is an elevational view, partially in section, of the marine drilling vessel of the present invention, modified so as to function as a portion of a marine riser extending from above the surface of the body of water to the marine bottom where it is connected with the subsea wellhead of a subaqueous well; and

FIGURE 7 is a cross-sectional view of the lower end of the spar buoy hull as shown in FIGURE 6 illustrating the means for suspending a section of marine riser pipe in the lower end of the spar buoy hull.

The invention comprises a floating drilling vessel consisting of a shipshaped platform attached by a pivotable arrangement to a longitudinally elongated spar buoy hull and means for adjusting the orientation of the spar buoy hull with respect to the platform, whereby the longitudinal dimension of the spar buoy hull is vertically oriented so as to depend deep into the water during drilling, and floats with its longitudinal dimension horizontally oriented along the surface of the water, behind the shipshaped platform to form a composite shipshaped vessel, when it is being transported, the deck of the platform remaining horizontal in all positions of the spar buoy hull.

Now looking to FIGURES 1 and 2, the marine drilling vessel, generally designated 10, consists of a spar buoy hull .12 and a shipshaped platform 14. The platform 14 is pivotally connected to the upper end of the spar buoy hull 12, being suspended between a pair of spaced arms 18 of a bifurcated section or yoke 16. The platform 14 has a shipshaped hull 19 and an above-surface working deck 20 with a drilling rig 21 mounted thereon above a central drilling well or moonpool (not shown) while the spar buoy hull 12 is an elongated cylindrical column having a central vertical well 22 coaxial with and beneath the moonpool of the shipshaped platform 14 when the vessel is in the position shown in FIGURE 2. An annulus 24, between the wall of the central well 22 and the outer wall of the spar buoy 12, is longitudinally compartmented by bulkheads 26 to form watertight compartments 27 that can be separately and controllably flooded to function as buoyancy/ ballast tanks.

In FIGURE 1, the marine drilling vessel 10 is shown as it would be positioned when moving toward a remote marine site. The shipshaped platform 14 and the spar buoy hull 12 are both floating on the surface 28 of a body of water 30 and may be locked in position with respect to each other by means which will be later described. When the marine drilling vessel -10 is in the position shown in this view, the longitudinal dimension of the hull 19 of the platform is parallel to the longitudinal dimension of the spar buoy hull 12 forming a substantiall shipshaped sea-going vessel capable of traversing an ocean at about the speed of a large tanker.

As shown in FIGURE 2, the spar buoy hull 12 is floating vertically Suspended in the body of water 30 with the platform 14 located at a desired distance above the surface 28 supported by the connecting section or yoke 16. A drill string 32, suspended from the drill rig 21 on the platform 14, extends through the central well 22 of the spar buoy 12 and into a marine bottom 34. While the marine drilling vessel 10 is in the position shown in FIGURE 2, the platform 14 is locked against movement relative to the spar buoy hull 12 to prevent any tilting of the platform 14 due to the shifting of equipment on the decks thereof.

In FIGURE 3 is illustrated a portion of one of the arms 18 incorporating a means for selectively rigidly fixing or locking the platform 14 with respect to the spar buoy hull .12. The upper end of the representative arm 18 has a cylindrical aperture 36 in the inwardly facing surface thereof. The opposing arm 18 has a coaxial cylindrical aperture 36 in the inwardly facing surface thereof. Fixed to the opposite sides of the shipshaped hull 19 of the platform 14 are large backing plates 38, each carrying a circular pattern, or configuration, of roller bearings 40, the roller bearings 40 being journaled on stub shafts 42 extending perpendicularly from the outer faces of the backing plates 38, and into the interior of the apertures 36 in the corresponding arms 18 so that the roller bearings 40 bear on the inner wall of the apertures 36 for pivotally mounting the platform 14 between the arms 18 of the connecting section or yoke 16. A pair of pivotal brake shoes 44 is coaxially journaled on a shaft 46 fixed to the outer face of each backing plate 38 radially inward of the circular configuration of roller bearings 40 and is designed to coact with an annular drum 48 concentrically mounted, on each of the arms 18, within the interior of the respective aperture 36. A circular internal rack 50 is fixed to the inner wall of the annular drum 48 and meshes with a pinion 52 mounted on a shaft 54 journaled through the backing plate 38 and driven by a motor (not shown) on the above-surface deck 20 of the platform 14. Shafts 56, also journaled through the backing plates 38, and driven from a motor (not shown) mounted on the deck 20 of the platform 14, each have a reel 58 fixed on the outer end thereof exterior of the backing plates 38. Pairs of cables 60 are interconnected between each of the reels 58 and each pair of brake shoes 44 such that when the reels 58 are rotated in one direction, the pairs of brake shoes 44 are clamped tightly against the annular drums 48 and when the reels 58 are rotated in the opposite direction, a predetermined distance, the pairs of brake shoes 44 are released from coacting with the drums 48.

When the marine drilling vessel 10 is in either of the positions shown in FIGURES 1 or 2, the pairs of brake shoes 44 are held tightly against the drums 48 to prevent any relative movement of the platform 14 with respect to the spar buoy hull 12. When the vessel 10 is to be reoriented from one of the illustrated positions to the other, the brake shoes 44 are deactivated by rotating the drum 48 and the change of position is made by adjusting the buoyancy in the various compartments 27 of the spar buoy hull 12. The gear sets, consisting of the pinions 52 and the internal racks 50, provide a fine adjustment of the relative position of the platform 14 with respect to the spar buoy hull 12. After the final adjustments have been made, the reel 58 is counter-rotated to re-establish contact between the brake shoes 44 and the annular drum 48 to lock two sections of the marine vessel 10 together.

In reorienting the spar buoy hull 12 from the position shown in FIGURE 1 to the position shown in FIGURE 2, enough compartments 27 should be flooded to obtain a negative buoyancy, submerging completely the spar buoy hull 12 and allowing it to hang suspended from the then supporting floating platform 14. Once the spar buoy hull 12 has attained the vertical orientation shown in FIGURE 2 and the position of the spar buoy hull 12 has been finely adjusted with respect to the platform 14, and the spar buoy hull 12 is locked in place with respect to the platform 14, some of the compartments 27 are blown free of water, by compressed air, causing the spar buoy hull 12 to rise partly out of the body of water 30 and support the platform 14 above the surface 28 as shown in FIGURE 2. The buoyancy/ballast tanks in the spar buoy hull 12 should have a capacity sufiicient to support the platform 14 forty feet or more above the surface 28 where it is relatively isolated from the surface waves. The reverse procedure would be followed for bringing the drilling vessel back to the position shown in FIGURE 1.

Although bottom anchoring systems have been successfully devised for deep water floating drilling operations, it is expected that a marine vessel such as the spar buoy type of the present invention would, in fact, be dynamically positioned. For this purpose an upper ring of propeller driving propulsion motors 62, and a lower ring of propeller driving propulsion motors 64, are fixed to the spar buoy hull 12. These motors 62 and 64, in combination, can control the drift of the marine drilling vessel 10 as well as its attitude in the body of water 30.

In FIGURE 2, alternative techniques for locating the marine drilling vessel 10 over a subaqueous borehole 66 are illustrated. One method of locating the vessel 10 over a marine site is by placing a plurality of acoustic transponders 68 on the marine bottom 34, in a pattern around. the borehole 66, and mounting corresponding acoustical transducers 70 on the lower end of the spar buoy hull 12 for receiving signals therefrom. Each of the transducers 70 may be keyed to respond to a single one of the transponders 68 so as to provide not only an indication of lateral positioning but also of radial positioning. Another method of locating the vessel 10 over a site utilizes the displacement of the drill string 32 in the lower end of the spar buoy hull 12, the drill string 32 being suspended from the drilling rig 21 on the above-surface deck 28 of the platform 14 and extending through the well 22 of the spar buoy hull 12 and into a borehole 66 in the marine bottom. An off-center position of the drill string 32 in the central well is an indication of a corresponding deviation of the vessel 10 from directly over the borehole in the marine bottom 34. A position indicating means consisting of a photoelectric position sensing means, generally designated 72, located at an observation area within the lower end of the cylindrical well 22, shown in detail in FIGURE 4, has two banks of photocells 74 and 76 mounted at 90 relative to each other around the circumference of the well 22 and at different axial levels. A bank of light sources 78, 80 is mounted diametrically across the well 22 from each bank of photosensitive devices 74 and 76, respectively. Each light source 78, 80 consists of a tubular compartment 82 having an open end facing the well 22 of the spar buoy hull 12. Within each compartment is a light bulb 84 and a focusing lens 86. A transparent plate 88 seals the open end of each of the tubular compartments 82 which opens into the central well 22. The light emitted from the bulb 84 at a source 78 is focused through the respective lens 86 into a narrow beam of light 90 to impinge on a corresponding photocell 74 diametrically opposite. In a similar manner, a beam of light 91 originating in a source 80 is focused to impinge on the corresponding photocell 76. The light beams 90, 91 of each bank 78, 80, respectively, are preferably parallel to form -a uniform grid; however, the beams 90, 91 of the two parallel banks 78, 80 can cross at any convenient angle. Normally 90 is the most convenient arrangement.

The light bulbs 84 of both banks may be individually grounded (not shown) and wired in parallel to a single power source 92 here shown as a battery 93. The electric voltage generated in the photocells 74 and 76, corresponding to the light impinged thereon from the light sources 78 and 80, is amplified by individual amplifiers 94 and energizes through respective wires 96 the corresponding light bulbs in a visual display instrument 98 (FIGURE 5) that would be mounted on the deck 20 of the platform 14 where it could be observed by an operator who could in turn control the propulsion motors 62 and 64 to bring the marine drilling vessel 10 back over the borehole 66.

The display instrument 98 consists of two banks of parallel transparent light conducting elements such as glass or Lucite rods 100 and 101 extending across the instrument 98 beneath the circular transparent face thereof, the banks of parallel rods being perpendicular to each other to form a grid arrangement which corresponds to the light beams 90 and 91, respectively, of the position sensing means 72 of FIGURE 4. A separate light bulb 102 is mounted in a shielding case 103 adjacent an end of each of the rods 100 and 101. The light bulbs 102, associated with each of the rods 100 and 101, are electrically connected, through amplifiers 94, to the photocells 74 and 76, respectively. When the central passage 22 is empty, all of the rods 100 and 101 in the display instrument 98 are illuminated. The beams of light 90 and 91, emitted by the light sources 78 and 80, impinge on the photocells 74 and 76, creating an electrical potential in each of the photocells. An electric current is created in each circuit containing the light bulbs 102, activating the bulbs and illuminating the respective rods 100 and 101. When a drill string is suspended in the passage 22, all of the rods are illuminated except for one rod 100 and one rod 101. A beam of light 90, emitted by a light source 78 is blocked by the drill string 32 before it can reach the opposing photocell 74, and therefore no electrical potential is generated in the photocell 74. The light bulb 102, associated with the rod 100' in the display instrument 98, is not activated and the interior of the glass rod 100' is not illuminated. The beam of light 91' emitted by a light source is also blocked by the drill string 32 before it can reach the photocell 76 and therefore the light bulb 102, associated with the rod 101 is not activated and the interior of the glass rod 101' is not illuminated. The point of intersection 104 of the unlighted glass rods 100 and 101' corresponds to the position of the drill string 32 or any other object in the lower end of the central well 22. This position would in turn vary as the position of the vessel 10 with respect to the borehole 66. In the previously described arrangement, the display rods 100' and 101 are not lighted, forming a dark pattern in contrast with the lighted surrounding rods. It is possible to design the inverse arrangement where the rods 100 and 101, corresponding to the interrupted beams and 91', are the rods that are lighted to contrast with the unlighted surrounding rods and 101. It is well within the skill of the art to provide a system for automatically controlling the propulsion motors 62 and 64 from either of the position indicating means described.

An open drill string 32, extending from the platform 14 directly to the borehole 66, shown in FIGURE 2, would be acceptable if coring operations were being conducted where water could be used as the drilling circulation fluid. While such operations may be successfully conducted a few hundred feet into the underlying formations, water is not heavy enough to prevent blowouts, and for drilling a wildcat or production well provision must be made for returning the heavy drilling mud, injected into the borehole 66 through the drill string 32, to the deck 20 of the plat-form 14. One method of returning the mud when using an open drill string would be by utilizing a submerged drilling wellhead system of the type described in the R. F. Bauer et a1. Patent No. 2,808,229, issued Oct. 1, 1957, in which the drilling mud is conducted back to the surface vessel from a point adjacent the marine bottom by a flexible line. However, it has been found to be more satisfactory to provide a marine riser pipe between a subsea wellhead and a surface vessel to guide the drill string between the vessel and the wellhead and for the annulus thereof to act as a return conduit for the drilling mud.

In FIGURE 6, there is shown a method for connecting the platform 14 of the drilling vessel with a subsea borehole 66 by using the central well 22 of the spar buoy hull 12 as a portion of a marine riser. A section of marine riser pipe 106 is suspended in the lower end of the central well 22 and depends to the subsea wellhead 108 and a blowout preventer stack 110 capping the wellbore 66'. The lower end of the marine riser is connected to the blowout preventer stack v110 through a universal joint 112 and a sliding joint 114.

One method of connecting the marine riser pipe 106 to the spar buoy hull 12, as shown in larger scale and numbered in FIGURE 7, includes a pair of slips 116 set in cavities 118 in the wall 120 of the well 22. The slips 116 are controlled from the deck of the platform 14 through a manifolding arrangement 122 and a hydraulic line 124, extending to a pressure source on the deck 20 through the compartments 27. A pair of inflatable circular rubber seals 126 are fixed to the inner wall 120 of the central well 22, above and below the ship cavities 118. The marine riser pipe 106 can be hung in the well 22 by a pipe string connected thereto by a releasable connection such as a J-connector joint. When the marine riser pipe 106 has been lowered through the spar buoy hull 12 until the upper end thereof is just .above the upper one of the seals 126, the fluid line 124 is pressured up, breaking the shear pins 128 which hold the slips 116 in the wall 120 and driving the slips 116 downwardly into engagement with the marine riser pipe 106. By then pressuring up the pneumatic seals 126, through a flexible line 130 also extending up through the compartments 27 to a pressure source on the deck of the platform 14, a fiuidtight joint is produced. The heave of the drilling vessel 10 is taken up in the sliding joint 114 of the riser pipe 106 and the slight movement of the vessel 10 from directly above the borehole 66 is compensated for by a universal joint v112, the flexibility of the riser pipe 106 compensating for other movements such as roll. A short riser section 132 is shown as being held in the upper end of the well 22 by a pair of slips 134, to direct the drilling mud from the upper end of the central well 22 to a central well or moonpool extending through the platform 14. The riser section 132, which could also be suspended by slips mounted in the wall of the moonpool, is necessarily removable regardless of where it is supported, to provide clearance for the relative movement between the platform 14 and the spar lbuoy hull 12 when converting between a shipshaped vessel and an above surface drilling station.

The riser pipe sections 106 and 132 may be made up and stored in the central wells of the spar buoy hull 12 and the platform 14, respectively, when the vessel 10 is in the position shown in FIGURE 1 or the riser pipe sections may be made up from the drilling deck in the same manner that drill pipe is made up just prior to being used. The utilization of the spar buoy hull 12 as a portion of the marine riser serves several functions. First, it does not shield the drill string 32 therewithin from the photoelectric position indicating system 72 as would a separate conductor pipe hung from the deck 20 of the platform through the central well 22. Second, it lessens the amount of actual riser pipe 106 that is needed, which in turn lowers the weight and cost of the entire apparatus.

A problem associated with utilizing some conventional drilling muds returning through the central well 22 is they are opaque to light. In the advent that light opaque drilling Inuds are used, the photoelectric sensing means 22 can be replaced by an ultrasonic or acoustic system. However, due to the difficulties involved in forming a very narrow sonic beam, the emitters or oscillators should all be of different frequencies and the respective receivers attuned to those frequencies. Purely mechanical sensing means could also be used as could capacitance or magnetic measuring systems.

It is envisioned that the marine drilling vessel 10 will be self-propelled as indicated by a propeller 136 connected to a propeller shaft extending out of the rear end of the ship shaped hull 19 of the platform 14. When the spar buoy hull 12 is in the position shown in FIG- URE 1, its propulsion motors 62 and 64 will have no effect on the movement of the vessel 10 through the body of water 30 and therefore the engines within the platform 14, for driving the propeller 136, must be powerful enough to transport the entire vessel 10 across the surface 28 of the body of water 30 at a reasonable speed. As an auxiliary means of propelling the vessel 10, the ones of the propulsion motors 62 and 64 that are under water in the position of FIGURE 1 may be pivotaible into a position in which their propellers face the rear of the vessel 10 and laid in driving the vessel 10 through the water. Separate rearwardly directed auxiliary motors (not shown) may also be mounted on the spar buoy hull 12 for propelling the vessel 10 more quickly through the water.

The annulus 24 of the spar buoy hull 12 can be used, during transportation, to carry fuel for the powerful motors necessary to drive such a large vessel 10 across the vast stretches of an ocean. Drilling mud and any other fluids that are necessary at a drilling site can also be stored in the compartments 27 of the annulus 24 which may be 400 feet long, or longer, in an actual vessel. Therefore, the spar buoy hull 12 can serve as a tanker as well as a drilling ship and the vessel 10 will be almost self-suflicient, requiring no barges to erect the unit and only minimal visits from supply ships. If the space in the annulus 24 of the spar buoy hull 12 is not large enough to carry all the fuel, drilling mud, etc., plates can be welded over the well 22, at both ends thereof, and this temporary compartment can also be used for storage in transit.

What is claimed is:

1. A vessel for supporting equipment buoyantly above the surface of a body of water at a marine site comprising: a platform having at least one horizontal deck for mounting equipment thereon above the surface of a body of water; a single longitudinally elongated spar buoy hull; means for connecting said platform to said spar buoy bull to provide adjustability of said spar buoy hull between a first and a second position of said spar buoy hull with respect to said platform, said first position being with the longitudinal dimension of said spar buoy hull substantially parallel to said deck of said platform, and said second position being with said longitudinal dimension of said spar buoy hull substantially perpendicular to said deck of said platform and centrally located therebeneath, whereby when said vessel is to be transported across a body of water, said vessel floats in a first position with said spar buoy hull in said first position, substantially parallel to the surface of said body of water, to reduce the hydrodynamic drag of said vessel and whereby when said vessel is located at a marine site, said vessel floats is a second position with said spar buoy hull in said secend position, depending substantially vertically into said body of water to form a stable spar buoy marine structure relatively unaffected by wave action.

2. A vessel for supporting equipment buoyantly above the surface of a body of water at a marine site comprising: a platform having a shipshaped hull and at least one horizontal deck for mounting equipment thereon above the surface of a body of water; a longitudinally elongated spar buoy hull; means for connecting said platform to said spar buoy hull to provide adjustability of said sp ar buoy hull between a first and a second position of said spar buoy hull with respect to said platform, said first position being with the deck of said platform parallel to the longitudinal dimension of said spar buoy hull, and said second position being with said deck of said platform substantially perpendicular to said longitudinal dimension of said spar buoy hull, whereby when said vessel is to be transported across a body of water, said vessel floats in a first position with said spar buoy hull in said first position, substantially parallel to the surface of said body of water, the shipshaped hull of said platform being buoyantly supported in the body of water with said spar buoy hull forming a single composite elongated buoyant shipshaped hull to reduce the hydrodynamic drag of said vessel and whereby when said vessel is located at a marine site, said vessel floats in a second position with said spar buoy hull in said second position, depending substantially vertically into said body of water to form a. stable marine structure relatively unaffected by wave action.

3. A vessel for supporting equipment buoyantly above the surface of a body of water at a marine site comprising: a platform having at least one horizontal deck for mounting equipment thereon above the surface of -'a body of water; a longitudinally elongated spar buoy hull having a central well extending therethrough; means for connecting said platform to said spar buoy hull to provide adjustability of said spar buoy hull between a first and a second position of said spar buoy hull with respect to said platform, said first position being with the longitudinal dimension of said spar buoy hull substantially parallel to said deck of said platform, and said second position being with said longitudinal dimension of said spar buoy hull substantially perpendicular to said deck of said platform, whereby when said vessel is to be transported across a body of water, said vessel floats in a first position with said spar buoy hull in said first position, substantially parallel to the surface of said body of water, to reduce the hydrodynamic drag of said vessel and whereby when said vessel is located at a marine site, said vessel floats in a second position with said spar buoy hull in said second position, depending substantially vertically into said body of water to form a stable marine structure relatively unaffected by wave action.

4. A vessel as recited in claim 3 wherein there is a well extending through said platform, said wells extending through said spar buoy hull and said platform being coaxial when said vessel is in said second position whereby a drill string, suspended from a drilling rig mounted on said deck of said platform over said well through said platform, could extend to the marine bottom through both of said wells.

5. A vessel for supporting equipment buoyantly above the surface of a body of water at a marine site comprising: a platform having at least one horizontal deck for mounting equipment thereon above the surface of a body of water; :a longitudinally elongated spar buoy hull; means for adjustably connecting said platform to said spar buoy hull; means associated with said spar buoy hull for positioning said spar buoy hull between a first and a second position of said spar buoy hull with respect to said platform, said positioning means comprising longitudinally spaced watertight compartments forming buoyancy/ ballast tanks in said spar buoy hull whereby the controlled flooding ofsaid buoyancy/ballast tanks change the position of'said spar buoy hull with respect to said platform, selectively actuable means, associated with said means for adjustably connecting said platform to said spar buoy hull, for rigidly fixing said spar buoy hull with respect to said platform whereby said means for rigidly fixing said spar buoy hull with respect to said platform is actuated to fix said spar buoy hull with respect to said platform to hold said vessel in said first and second positions and is deactivated during the repositioning of said spar buoy hull from one of said first and second positions to the other of said positions, said first position being with the longitudinal dimension of said spar buoy hull substantially parallel to said deck of said platform, and said second position being with said longitudinal dimension of said spar buoy hull substantially perpendicular to said deck of said platform, said buoyancy/ ballast tanks being of a capacity sufiicient to raise said platform above the surface of a body of water when said vessel is in said second position, whereby when said vessel is to be transported across a body of water, said vessel floats in a first position with said spar buoy hull in said first position, substantially parallel to the surface of said body of water, to reduce the hydrodynamic drag of said vessel and whereby when said vessel is located at a marine site, said vessel floats in a second position 'with said spar buoy hull in said second position, depending substantially vertically into said body of water and said platform fully above the surface of said body of water to form a stable marine structure relatively unaffected by wave action.

6. A vessel as recited in claim 5 wherein the means for connecting said spar buoy hull to said platform is a pivotal connection; at least one brake drum fixed to one relatively rotatable element of said pivotal connection and at least one brake shoe mounted on the other relatively rotatable element of said pivotal connection; and means for selectively actuating said at least one brake shoe to force said at least one brake shoe against said at least one brake drum to fix said spar buoy hull with respect to said platform.

7. A vessel as recited in claim 6 wherein said pivotal connection comprises a yoke fixed at one end of said spar buoy hull; means for rotatably journaling said platform between opposing arms of said yoke; brake drums concentrically mounted on said opposing yoke arms adjacent said platform; and at least one brake shoe pivotally mounted on said platform in conjunction with each of said opposing yoke arms.

8. A vessel as recited in claim '7 wherein there is a pair of coaxially mounted brake shoes facing opposite sides of each of said brake drums; a cable winding reel mounted on a rotatable drive means on said platform and located adjacent each brake drum opposite the coaxial mounting point for said pair of brake shoes; and a cable extending between each of said brake shoes and said reel 'whereby when said reels are rotated to one position the pairs of brake shoes are actuated and press firmly on said brake drums and when said reels are rotated to a second position, said pairs of brake shoes are deactivated and are not firmly pressed against said brake drum.

9. A vessel for supporting equipment buoyantly above the surface of a body of water at a marine site comprising: a platform having at least one horizontal deck for mounting equipment thereon above the surface of a body of water; a longitudinally elongated spar buoy hull; means for connecting said platform to said spar buoy hull to provide adjustability of said spar buoy hull between a first and a second position of said spar buoy hull with respect to said platform, said means for adjustably connecting said platform to said spar buoy hull comprises means for rotatably journaling said platform and means for selectively adjusting the position of said spar 'buoy hull with respect to said platform comprising meshing gear means for rotating said platform with respect to said spar buoy hull, said first position being with the longitudinal dimension of said spar buoy hull substantially parallel to said deck of said platform, and said second position being with said longitudinal dimension of said spar buoy hull substantially perpendicular to said deck of said platform, whereby when said vessel is to be transported across a body of water, said vessel floats in a first position with said spar buoy hull in said first position, substantially parallel to the surface of said body of Water, to reduce the hydrodynamic drag of said vessel and whereby when said vessel is located at a marine site, said vessel floats in a second position with said spar buoy hull in said second position, depending substantially vertically into said body of water to form a stable marine structure relatively unaffected by wave action.

10. A vessel as recited in claim 9 wherein said means for rotatably journaling said platform comprises a yoke fixed to one end of said spar buoy hull, said platform being journaled between the arms of said yoke.

11. A vessel as recited in claim 10 wherein said means for journaling said platform comprises coaxial cylindrical apertures in the opposing faces of each of said yoke arms; and a plurality of rotatable bearings mounted on a plate fixed to said platform opposing each of said cylindrical apertures, said bearings being spaced around the circumference of a circle so all of said bearings contact the inner wall of said opposed cylindrical aperture.

12. A vessel as recited in claim 11 wherein a circular internal rack is concentrically fixed within at least one of said cylindrical apertures; a pinion meshing with said racks, said pinion being mounted on a drive shaft rotatably mounted coaxially with the pivotal axis of said platform; .and means for rotating said drive shaft.

13. A vessel for supporting equipment buoyantly above the surface of a body of water at a marine site comprising: a platform having at least one horizontal deck for mounting equipment thereon above the surface of a body of water; a longitudinally elongated spar buoy hull; means for connecting said platform to said spar buoy hull to provide adjustability of said spar buoy hull between a first and a second position of said spar buoy hull with respect to said platform; primary and secondary means associated with said spar buoy hull for positioning said spar buoy hull with respect to said platform, said primary means comprising longitudinally spaced watertight compartments forming buoyancy/ballast tanks in said spar buoy hull whereby the controlled flooding of said buoyancy/ballast tanks change the position of said spar buoy hull with respect to said platform; a secondary positioning means comprising a mechanical connection extending between said platform and said spar buoy hull; and means for actuating said mechanical connection to secondarily reposition said spar buoy hull with respect to said platform; said first position of said spar buoy hull with respect to said platform being with the longitudinal dimension of said spar buoy hull substantially parallel to said deck of said platform, and said second position being with said longitudinal dimension of said spar buoy hull substantially perpendicular to said deck of said platform, whereby when said vessel is to be transported across a body of water, said vessel floats in a first position with saidspar buoy hull in said first position, substantially parallel to the surface of said body of water, to reduce the hydrodynamic drag of said vessel and whereby when said vessel is located at a marine site, said vessel floats in a second position with said spar buoy hull in said second position, depending substantially vertically into said body of water to form a stable marine structure relatively unaffected by wave action.

14. A method of utilizing the vessel of claim 13 at a marine site when said vessel is transported to a marine site in said first position, comprising the following steps in the order recited:

(a) flooding said buoyancy/ballast tanks of said spar buoy hull until said spar buoy hull attains a negative buoyancy and is suspended beneath said platform, which is buoyantly floating on the surface, whereby said spar buoy hull moves into substantially said second position;

(b) actuating said secondary positioning means, connected between said spar buoy hull and said platform, to position finally said spar buoy hull with respect to said platform;

(c) rigidly fixing said spar buoy hull with respect to said platform; and

(d) evacuating said buoyancy/ballast tanks until said spar buoy hull has enough positive buoyancy to raise the platform a distance above the surface of said body of water.

15. A means for indicating the position of an object in an observation area including: a position sensing means extending at least across said area under observation, said position sensing means comprisinga first energy emitting means located to one side of said observation area for transmitting parallel beams of energy in a first plane across said area under observation; a plurality of first energy receiving means positioned across said observation area from said first energy emitting means to each receive one of said beams transmitted across said observation area from said first energy emitting means; a second energy emitting means located to one side of said observation area for transmitting parallel beams of energy in a second plane parallel to said first plane across said observation area, said parallel beams transmitted by said first energy emitting means being nonparallel to said parallel beams transmitted by said second energy emitting means; a plurality of second energy receiving means positioned across said observation area from said second energy emitting means to each receive one of said beams transmitted across said observation area from said second energy emitting means; a display means spaced from said position sensing means, said display means comprising a display area similar in shape to said observation area; a plurality of elongated transparent light conducting means extending across said display area in a pattern corresponding to the pattern of said energy beams to be transmitted across said observation area; a light source being associated with each of said transparent light conducting means; means for directing light emitted from each of said light sources fully through said respective light conducting means; and means for connecting said each of said light sources with the respective energy receiving means to cause selected light sources to be energized forming a light and dark pattern of said transparent light conducting means including a pair of contrasting and intersecting transparent light conducting means, the intersection of which indicates the position of the object in said observation area, which has blocked a pair of nonparallel beams of energy.

16. The position indicating means of claim 15 wherein said energy emitting means comprises at least one source of light, and said energy receiving means comprises photocells.

17. The position indicating means of claim 15 wherein said energy emitting means comprises sources of sonic energy.

18. The position indicating means of claim 16 wherein said means for connecting said each of said light sources with the respective photocell comprises a signal amplifying means.

19. The position indicating means of claim 15 wherein said transparent light conducting means comprises glass rods.

20. The position indicating means of claim 15 wherein said transparent light conducting means comprises Lucite rods.

21. A vessel for supporting equipment buoyantly above the surface of a body of water at a marine site comprising: a platform having at least one horizontal deck for mounting equipment thereon above the surface of a body of Water; a longitudinally elongated spar buoy hull; means for connecting said platform to said spar buoy hull to provide adjustability of said spar buoy hull between a first and a second position of said spar buoy hull with respect to said platform, said first position being with the longitudinal dimension of said spar buoy hull substantially parallel to said deck of said platform, and said second position being with said longitudinal dimension of said spar buoy hull substantially perpendicular to said deck of said platform, said vessel floating in said second position with said spar buoy hull depending substantially vertically into said body of water to form a stable marine structure relatively unaifected by wave action; selectively actuable propulsion units arranged on said spar buoy hull, and located beneath the surface of said body of water when said spar buoy hull is in said second position, said propulsion units being capable of locating dynamically said vessel when said vessel 'is in said second position; transponders fixedly placed with respect to the marine bottom, each of said transponders being keyed to emit a discrete signal transmitted by the body of water; corresponding transducers located on said marine vessel for receiving said signals, each of said corresponding transducers being keyed to receive the signal emitted by one of said transponders wherein said marine vessel can be laterally and radially positioned.

22. Apparatus for indicating the position of a floating vessel, as recited in claim 4, with respect to a borehole extending into the formations underlying a marine bottom when said vessel is in said second position; a drilling rig mounted'on the deck of said platform; a drill string having means connected to an end thereto to form said borehole in said marine bottom, said drill string being suspended from said drilling rig and extending through said aligned wells extending through said spar buoy hull and said platform, the intervening body of water, and into said borehole extending into said formations underlying said marine bottom; selectively actuatable propulsion units arranged on said spar buoy hull so as to be beneath the surface of said body of water when said vessel is in said second position, said propulsion units being capable of locating dynamically said vessel when said vessel is in said second position; and a position sensing means located in said central well of said spar buoy hull for providing an indication of the position of said drill string in said central well whereby an off-center position of said drill string in said central well indicates a corresponding deviation of said vessel from directly above the upper end of said borehole at said marine bottom.

23. A drilling vessel as recited in claim 22 wherein there is means for selectively actuating said propulsion units in response to the indicated deviation of said drill string from the axis of said central well whereby the drilling vessel is held substantially over said borehole.

24. A drilling vessel as recited in claim 23 wherein there are manual controls for selectively actuating said propulsion units, said controls being located on said platform; and display means connected to said position indicating means, said display means being located on said platform adjacent said manual controls for selectively actuating said propulsion units, said display means visually portraying the portion of said drill string in the central well at the axial position of said position indicating means.

25. A drilling vessel as recited in claim 24 wherein said position indicating means is located near the lower end of said central well.

26. A drilling vessel as recited in claim 23 wherein said position indicating means comprises a photoelectric device.

27. A drilling vessel as recited in claim 23 wherein said position indicating means comprises an acoustic device.

28. A drilling vessel as recited in claim 26 wherein said position indicating means comprises: a first light source means located to one side of said central well for transmitting parallel beams of light in a first plane across said central well; a plurality of photocells positioned across said central vwell from said first light source means to each receive one of said light beams transmitted across said central well from said first light source means; a second light source means located to one side of said central well for transmitting parallel light beams in a second plane parallel to said first plane across said central well, said parallel light beams transmitted by said first light source means being nonparallel to said parallel light beams transmitted by said second light source means; and a plurality of photocells positioned across said central Well from said second light source means to each receive one of said light beams transmitted across said central well from said second light source means.

29. A drilling vessel as recited in claim 28 wherein said display means comprises: a display area similar in shape to a cross section of said central well at the photoelectric device; a plurality of elongated transparent light conducting means extending across said display area in a pattern corresponding to the pattern of light beams to be transmitted across said central well; a plurality of third and fourth light source means, each of said third and fourth light source means being associated with one of said transparent light conducting means for directing the light from each of said third and fourth light sources fully through said respective light conducting means; and means for connecting each of said third and fourth light source means with said respective first and second light source means to cause selected ones of said third and fourth light source means to be energized forming a light and dark pattern of said transparent light conducting means including a contrasting pair of intersecting transparent light conducting means, the intersection of which indicates the position of said drill string in said central well.

30. A spar buoy drilling vessel comprising a platform supported above the surface of a body of water by a spar buoy hull; a central well extending through said spar buoy hull, said central well forming a portion of a marine conductor connecting a wellhead fixed to said marine bottom and a level within said spar buoy vessel above the surface of the body of water.

31. A spar buoy drilling vessel as recited in claim 30 wherein there is a removable marine conductor section extending between the lower end of said spar buoy hull and the upper end of said wellhead; and means for releasably supporting said marine conductor section in said central well and sealing said marine conductor section to said spar buoy hull.

References Cited UNITED STATES PATENTS 3,191,570 6/1965 Henderson 1l4144 3,273,526 9/1966 Glosten 114-05 3,336,572 8/1967 Paull et al. 166O.5

MILTON BUCHLER, Primary Examiner.

TRYGVE M. BLIX, Assistant Examiner.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3191570 *Mar 4, 1963Jun 29, 1965Phillips Petroleum CoHorizontal stabilization of floating structures
US3273526 *Nov 15, 1963Sep 20, 1966Lawrence R GlostenStable ocean platform
US3336572 *Apr 29, 1965Aug 15, 1967Texaco IncSonic means and method for locating and introducing equipment into a submarine well
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3516489 *Jan 5, 1968Jun 23, 1970Jergins Allen AOffshore drilling and well completion apparatus
US3572041 *Sep 18, 1968Mar 23, 1971Shell Oil CoSpar-type floating production facility
US3823564 *Feb 27, 1973Jul 16, 1974Brown & RootMethod and apparatus for transporting and launching an offshore tower
US4317174 *Feb 28, 1980Feb 23, 1982The Offshore CompanyRiser angle positioning system and process
US4625806 *Oct 19, 1984Dec 2, 1986Chevron Research CompanySubsea drilling and production system for use at a multiwell site
US4656959 *Mar 25, 1985Apr 14, 1987Moisdon Roger F GVertical ship
US4735526 *Sep 24, 1986Apr 5, 1988501 Mitsui Ocean Development & Engineering Co.Method for installing offshore jack-up structures
US6588359 *Sep 3, 2002Jul 8, 2003James M. PowersApparatuses and methods for at-sea cargo handling and rescue
US7703407 *Nov 26, 2007Apr 27, 2010The Boeing CompanyStable maritime platform
US8141511 *Nov 30, 2009Mar 27, 2012The Boeing CompanyStable maritime vehicle platform
US20110290499 *May 31, 2011Dec 1, 2011Ronald Van PetegemDeepwater completion installation and intervention system
USRE28614 *Jan 9, 1975Nov 18, 1975 Method and apparatus for transporting and launching an offshore tower
DE2462329A1 *Jun 12, 1974Oct 14, 1976Petroles Cie FrancaiseDrilling tool position and speed of penetration determn - for an underwater borehole drilled from a floating platform
WO2014032106A1 *Aug 29, 2013Mar 6, 2014Seacaptaur Ip LtdBuoy
Classifications
U.S. Classification114/264, 367/6, 405/200, 175/5
International ClassificationB63B35/44, E21B7/128
Cooperative ClassificationB63B2001/044, B63B35/4406, B63B35/4413, B63B2035/442, E21B7/128
European ClassificationB63B35/44A, E21B7/128, B63B35/44B