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Publication numberUS3004612 A
Publication typeGrant
Publication dateOct 17, 1961
Filing dateNov 5, 1956
Priority dateNov 5, 1956
Publication numberUS 3004612 A, US 3004612A, US-A-3004612, US3004612 A, US3004612A
InventorsKofahl David C
Original AssigneeRichfield Oil Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Submerged elevated well head structure
US 3004612 A
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Description  (OCR text may contain errors)

Oct. 17, 1961 D. c. KOFAHL SUBMERGED ELEVATED WELL HEAD STRUCTURE Filed Nov. 5, 1956 2 Sheets-Sheet 1 FIG. 2.

7 Hal.

R. w 0 y W z 1! Wm 2 w Oct. 17, 1961 D. c. KOFAHL 3,004,612

SUBMERGED ELEVATED WELL HEAD STRUCTURE Filed NOV. 5, 1956 2 Sheets-Sheet 2 INVENTOR. 041 40 6'. 60/5444.

United Stes This invention relates to drilling and production of oil from wells located in an offshore marine location and is particularly directed to improvements in a submerged elevated well head structure and to a method of drilling wells embodying such structure.

Wells in oifshore marine locations are now being drilled from floating vessels, with the rotary drill pipe passing through a well head structure located on the ocean floor. This technique is satisfactory where the water depths are not too great and where it is possible for divers to descend to the position of the well head structure. However, when the water depth exceeds that at which divers can operate readily, the drilling of wells is not feasible by conventional techniques.

It is an object of this invention to elevate the well head structure of a submerged oil well to a depth readily accessible to a deep sea diver and to support the well head structure at that depth. A related object is to support and stabilize the casing of the oil well between the ocean floor and the submerged elevated well head structure. Another object is to provide a rigid supporting structure to stabilize blowout preventers, casing heads and tubing heads at submerged locations considerably above the level of the ocean floor. Other and more detailed objects and advantages will appear hereinafter.

In the drawings:

FIGURE 1 is a side elevation in diagrammatic form showing a submerged elevated well head structure and illustrating a method of drilling the well from a floating vessel and for producing a well into a floating barge. FIGURE 2 is a sectional plan view taken substantially on lines 2-2 as shown in FIGURE 1.

FIGURE 3 is a side elevation on an enlarged scale showing a portion of the apparatus illustrated in FIG- URE 1.

Referring to the drawings, a support structure generally designated 10 includes a plurality of longitudinal tubular elements 11 arranged in the general form of a square, and a central tubular element 12. Horizontal braces 13 and diagonal braces 14 connect the longitudinal elements 11 and 12. Each of the tubular elements 11 and 12 has a clear passageway therethrough to permit insertion and withdrawal of drill tools and to allow circulation during jetting as described below. The tubular elements 11 may be straight or may be slightly bowed as shown in the drawing.

The structure 10 is fabricated on land by conventional methods and transported to the offshore marine location by barge. It is then lowered over the well site by means of a barge and derrick (not shown) and rested on the ocean floor 15. The lower ends 16 of the tubular elements 11 project below the remainder of the structure 10*. Water under pressure is pumped through the interior of the tubular elements 11 to cause a jetting action adjacent the lower ends 16 and thus cause the structure 10 to become embedded in the'ocean floor. The structure 10 is plumbed by selectively jetting the tubular elements 11. When the structure is plumbed so that column 12 is substantially vertical cement is pumped down each of the tubular elements 11 to provide a temporary anchor. The cement passes out through the lower ends 16 and returns upwardly to the level of the ocean floor.

Drill tools are then operated through each of the tubular elements 11 to drill through the loose ocean floor overburden and into consolidated formation. This drilling operation is preferably carried out by means of the apparatus shown in the drawings. The floating barge 17 carries a mast 18 and suitable rotary drilling apparatus 19 for rotating a drill pipe string 20. A bit 21 is carried at the lower end of the drill pipe string 20. A pair of guide cables 22 extend downward from the floating barge 17 and are attached to the upright posts 23 fixed on the submerged platform 24 of the structure 10. Guide cables 22 may be supported from within an access Well provided in the barge 17 and preferably are suspended from a rig floor on which the rotary drilling apparatus 19 may be located. A well head structure generally designated 25 is fixed on one of the tubular elements 11 adjacent the platform 24. This structure 25 includes a blowout preventer assembly 26 mounted on slidable guide tubes 27 loosely received on the posts 23.

A cross head 28 is provided with guide sleeves 29 which slide on the guide cables 22 and this cross head has a central sleeve 30 through which the drill pipe 20 loosely extends. The bit 21 is larger than the opening through the sleeve 30.

When the drill string 21 is lowered from the floating barge 17 the cross head 28 slides down the guide wires 22 and centers the bit 21 for entrance into the upper end 31 of the well head structure 25. Continued downward movement of the drill string 20 causes the bit 21 and drill string to pass axially through the well head assembly 25 and into the tubular element 11. The cement within the element 11 is drilled out and the bit passes downward through the lower ends 16 of the tubular element 11, forming a shaft 32 which is a prolongation of the tubular element 11. Cement is then pumped down the interior of the drill pipe string 20 out through the ports in the bit 21 and back through the shaft 32 to fix the drill pipe within the consolidated formation of the ocean floor. The drill pipe is then disconnected at the top of the platform 24 and serves to function as a reinforced concrete post within the tubular element 11. The same drilling and cementing operations are carried on sequentially with respect to each of the tubular elements 11. By this means the submerged structure 10 is securely anchored to the ocean floor.

The drill tools are then operated through the central column 12 to drill a prolongation shaft and a conductor pipe (not shown) is lowered through the interior of the column 12 and cemented in place. The drill tools are then operated through this conductor pipe to drill the Well. After completion of the drilling of the Well, the well head structure 33 is connected to the upper end of the central column 12 for producing oil from a well. This structure 33 is preferably similar to that disclosed in my copending application Serial No. 620,451, filed November 5, 1956 and employs a housing 34 which forms an enclosure for the tubing head. Well fluid produced through the tubing head passes outward through conduit 35 and flow line 36 to any convenient reservoir such as, for example, the barge 37.

Having fully described my invention, it is to be understood that I do not wish to be limited to the details herein set forth, but my invention is of the full scope of the appended claim.

I claim:

A submerged well head structure for a well in an oilshore marine location comprising in combination: a wholly submerged support structure having a plurality of tubular elements extending from the lower end to the upper end thereof, the lower ends of certain of the tubular elements extending into the ocean floor, a post fixed within each of the latter said tubular elements further projecting into the ocean floor, whereby the structure is rigidly fixed against movement, a submerged well head device fixed to the upper end of one of the other tubular elements laterally flexible guide means connected with the well head device and extending upwardly for guiding drilling tools into the well head device from a floating vessel at the ocean surface, and means on the floating vessel for rotating the drill tools.

References Cited in the file of this patent UNITED STATES PATENTS Flood et al. .L June 21, 1910 Gross Apr. 1, 1941 Tucker June 27, 1950 Samuelson Mar. 11, 1952 Evans et a1. May 12, 1953 7 Bauer et a1. Oct. 1, 1957 McNeill et al Oct. 1, 1957

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US962019 *Sep 30, 1909Jun 21, 1910John Garnar FloodDiving-bell apparatus for submarine work.
US2236682 *Dec 31, 1937Apr 1, 1941Standard Oil Dev CoMarine foundation and method of construction
US2512783 *May 4, 1946Jun 27, 1950Tucker Augustine JMarine drilling
US2589146 *Oct 6, 1949Mar 11, 1952Charles T SamuelsonSubmersible deepwater drilling apparatus
US2637978 *Apr 25, 1946May 12, 1953Stanolind Oil & Gas CoMarine drilling
US2808229 *Nov 12, 1954Oct 1, 1957Continental Oil CoOff-shore drilling
US2808230 *Jan 17, 1955Oct 1, 1957Continental Oil CoOff-shore drilling
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3125171 *Oct 27, 1958Mar 17, 1964 stewart iii
US3142343 *Dec 14, 1960Jul 28, 1964Shell Oil CoMethod and apparatus for drilling underwater wells
US3195639 *Oct 16, 1961Jul 20, 1965Richfield Oil CorpOff-shore drilling and production apparatus
US3204709 *Oct 21, 1963Sep 7, 1965Pacific Tugboat & Salvage CoDeep sea coring tower
US3313347 *Jun 23, 1965Apr 11, 1967Gray Tool CoWell completion procedures and apparatus
US3366173 *Sep 29, 1965Jan 30, 1968Mobil Oil CorpSubsea production system
US3378086 *May 13, 1966Apr 16, 1968Geocon LtdStationary overwater platform
US3379245 *May 17, 1966Apr 23, 1968Mobil Oil CorpTended drilling platform for multiwell subsurface completion
US3380520 *Feb 8, 1966Apr 30, 1968Offshore CoDrilling and production platform
US3424241 *Feb 24, 1967Jan 28, 1969Chevron ResMethod for drilling and working in offshore wells
US3430695 *Nov 8, 1967Mar 4, 1969Mobil Oil CorpMethod and apparatus for installing underwater wellhead support
US3442340 *Jun 9, 1967May 6, 1969Lowell B ChristensonMobile/fixed drilling and production structure
US3451493 *Mar 29, 1967Jun 24, 1969Storm James CDrilling apparatus and method
US3535884 *Jun 30, 1967Oct 27, 1970Sun Oil CoOffshore drilling and production structure
US3556210 *May 8, 1969Jan 19, 1971Johnson Vincent CDeep sea well drilling structure
US3610346 *Jun 1, 1970Oct 5, 1971Texaco IncMethod for oriented emplacement of well casing to achieve directional drilling
US3618661 *Aug 15, 1969Nov 9, 1971Shell Oil CoApparatus and method for drilling and producing multiple underwater wells
US3625281 *Apr 23, 1969Dec 7, 1971Rockwell Mfg CoWell completion method and apparatus
US3670507 *Sep 17, 1970Jun 20, 1972Texaco IncMarine drilling structure with curved drill conductor
US3685300 *Oct 19, 1970Aug 22, 1972Texaco IncMarine platform with curved support leg
US3687204 *Sep 8, 1970Aug 29, 1972Shell Oil CoCurved offshore well conductors
US3789559 *Nov 17, 1971Feb 5, 1974W KirkesProcess and apparatus for constructing foundations and setting prefabricated buildings thereon
US3941189 *Nov 18, 1974Mar 2, 1976Standard Oil CompanySubsurface wellhead shield
US4231682 *Jan 10, 1978Nov 4, 1980Entreprise D'equipements Mecaniques Et Hydrauliques E.M.H.Device for handling appliances on a sea bed
US4630681 *Feb 25, 1985Dec 23, 1986Decision-Tree Associates, Inc.Multi-well hydrocarbon development system
US5503526 *Jan 23, 1995Apr 2, 1996Neils; John J.Fire fighting fan with three point support
US5722494 *Oct 18, 1995Mar 3, 1998Union Oil Company Of CaliforniaOffshore well structure
USRE28860 *Jan 26, 1973Jun 15, 1976Shell Oil CompanyCurved offshore well conductors
USRE32623 *Oct 14, 1986Mar 15, 1988Shell Oil CompanyCurved offshore well conductors
DE2144570A1 *Sep 6, 1971Mar 16, 1972 Title not available
Classifications
U.S. Classification175/7, 166/368, 175/10, 175/9
International ClassificationE21B7/128, E21B33/037, E21B7/04, E21B33/03, E21B7/12
Cooperative ClassificationE21B7/122, E21B7/043, E21B33/037, E21B7/128
European ClassificationE21B7/12K, E21B7/128, E21B33/037, E21B7/04A