US3824943A - Drilling platform - Google Patents

Drilling platform Download PDF

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US3824943A
US3824943A US00233879A US23387972A US3824943A US 3824943 A US3824943 A US 3824943A US 00233879 A US00233879 A US 00233879A US 23387972 A US23387972 A US 23387972A US 3824943 A US3824943 A US 3824943A
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cells
sea
deck
platform
vertical
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US00233879A
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O Mo
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Mo och Domsjo AB
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    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
    • E21B43/01—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells specially adapted for obtaining from underwater installations
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B15/00—Supports for the drilling machine, e.g. derricks or masts
    • E21B15/02—Supports for the drilling machine, e.g. derricks or masts specially adapted for underwater drilling

Definitions

  • the platform is [56] References Cited monolithic and comprises a plurality of vertical cells UNITED STATES PATENTS of concrete.
  • a bottom deck closes the bottom of the 2,940,266 6 1960 Smith 61/465 vertical cells and is adapted to be Positioned p 55 4 below the sea surface and above the floor of the sea.
  • the vertical cells are arranged such that at least one 6 /465 but not all of the cells extend from the bottom deck to 2,972,973 2 1961
  • Thearle 3,154,039 10/1964 Knapp 3,273,526 9 1966 016m rh d g 11415 T the top deck and the center of gravity of the platform anning H4 .5 T v is below its center of buo anc 3,510,892 5/1970 Monnereau et al 9/8 7 y y 3,535,884 10/1970 Chaney 61/465 7 Claims, 2 Drawing Figures ,II'III' rIIII'II DRILLING PLATFORM
  • the invention relates to a floating drilling platform for drilling after and production of natural deposits under the sea.
  • a platform of that type which has a reduced cross-section at the floating line e.g. semi-submersible state
  • This very simple construction will, as showed below, offer many advantages compared with the conventional floating platforms.
  • FIG. 1 shows a vertical section B B through the platform and FIG. 2 shows a horizontal section A A.
  • 1 is a cell which is terminated under the water surface
  • 2 is a cell which is terminated above the water surface
  • 3 is a cell without a bottom which the drill 4 passes through.
  • 5 is the workingor service deck of the platform and 6 is the drilling tower.
  • the tubes may have varying wall thickness and diameter. It is, however, an advantage if the variations are small, since the platform in that case can be made by means of slip forms.
  • the cells may during the drilling be filled withair,
  • ballast material There must always be some air present for buoyancy, while sand is an excellent ballast material. Other solid ballast material, of course, can be used. Water will be the natural medium for trimming.
  • the cells may also be used for tanks, e.g. for oil storage or as a dumping place for polluted materials.
  • a series of advantages are achieved in that the drilling takes place through a tube.
  • the work will not be hindered by waves or ice.
  • Such a solution means a big advantage, especially for the divers, since their work often becomes restricted due to the difficulties in getting up and down through the wave area.
  • the tube will also beable to collect spill of oil, and prevent the oil from spreading in the sea.
  • the platform will extend downwards much deeper than other floating platforms.
  • the figure shows a platform which has a sub structure nearly double the height of the drilling tower,
  • a platform according to the invention will thus not need to interrupt the work due to bad weather. This is of large importance in so called wild-cat"-drilling, and absolutely of vital improtance for production. None of the existing floating platforms may be used for production, namely because production must go on continously irrespective of the weather.
  • the weight and stability of the platform is also necessary, if it is to be provided with industrial plants, fishplate arrangements etc.
  • the service deck can thus be provided with industrial equipment, quay installations, and the like.
  • the large sub structure of the platform is also advantageous for conventional anchoring, since the anchors may be fastened far down and thus obtain a greater effect since the chain or the wire remains lying more horizontally. Dynamic anchoring may be employed.
  • the cell formed concrete structure is in itself particularly favourable.
  • the construction can take up very large pressure-forces, since buckling problems practically do not exist. This is of importance with regard to the large water pressures in question, and with more occasional local stresses, e.g. from ice.
  • a platform according to the invention offers no production difficulties, since the production can be performed exclusively by means of simple method and modest aids.
  • a natural way is to cast the bottom and a bit of the walls in a dry-dock, tow this out to a deep sea area and thereafter erect the walls by means of slip forms, while the platform gradually sinks down in the water.
  • the platform may be provided with its own propulsion equipment.
  • the platform according to the invention has the following advantages:
  • a floating platform for drilling after natural deposits beneath the floor of the sea having a reduced cross section at the sea surface, a service deck above the sea surface and a sub structure extending downwardly below the sea surface
  • said platform is monolithic and mobile, and comprises a plurality of contiguous vertical cells of concrete at least one of the cells lengthened to above sea level to form a support for a service deck, a service deck permanently fixed to said platform, the nonlengthened cells located a substantial distance below the deck section so that the top of said non-lengthened cell or cells is at a substantial depth below the surface of the sea, a drilling structure on said service deck, a bottom deck closing the bottom of said vertical cells and adapted to be positioned deep below the sea sur- 7 face and above the floor of the sea, the whole structure being constructed and arranged such that the center of gravity of said platform is below the center of buoyancy thereof.
  • An improved platform according to claim 1 further including a drill extending from said service deck down through one of said verticle cells to the sea floor.
  • An improved platform according to claim 1 wherein said platform includes a first group of adjacent vertical concrete cells extending from said service deck to said bottom deck and a second group of vertical concrete cells in surrounding adjacency with said first group and extending from said bottom deck upwards to ballast material.

Abstract

A floating platform for drilling after natural deposits beneath the floor of the sea. The platform has a reduced cross section at the sea surface, a service deck above the sea surface, and a substructure extending downwardly below the sea surface. The platform is monolithic and comprises a plurality of vertical cells of concrete. A bottom deck closes the bottom of the vertical cells and is adapted to be positioned deep below the sea surface and above the floor of the sea. The vertical cells are arranged such that at least one but not all of the cells extend from the bottom deck to the top deck and the center of gravity of the platform is below its center of buoyancy.

Description

United States'Patent 11 1 1111" 3,824,943
M0 g 1451 July 23,1974
1 1 DRILLING PLATFORM 3,572,043 3 1971 Clara ..61 46 3,681,923 8/1972 Hyde [76] Inventor- Gmnsundvelen 3,708,987 1 1973 Roulet (it al. 61 46 Nesbru, Norway [22] Filed: Mar. 13, 1972 OTHER PUBLICATIONS The 011 and Gas Journal of Sept. 14, 1970, pages 60,
[21] Appl. No.: 233,879 1 [30] Foreign Application Priority Data Primary Examiner-Jacob Shapiro Mar. 16, 1971 Norway 1008/71 Attorney Agent Taylor and Hinds [52] US. Cl. 114/.5 D, 114/.5 T, 61/465, ABSTRACT 175/7 A floating platform for drilling after natural deposits beneath the floor of the ea The platform has a re- Field of Search 61/465, T, duced cross section at the sea surface, a service deck 114/5 D; 9/8; 175/7 above the sea surface, and a substructure extending downwardly below the sea surface. The platform is [56] References Cited monolithic and comprises a plurality of vertical cells UNITED STATES PATENTS of concrete. A bottom deck closes the bottom of the 2,940,266 6 1960 Smith 61/465 vertical cells and is adapted to be Positioned p 55 4 below the sea surface and above the floor of the sea. 61/465 X The vertical cells are arranged such that at least one 6 /465 but not all of the cells extend from the bottom deck to 2,972,973 2 1961 Thearle 3,154,039 10/1964 Knapp 3,273,526 9 1966 016m rh d g 11415 T the top deck and the center of gravity of the platform anning H4 .5 T v is below its center of buo anc 3,510,892 5/1970 Monnereau et al 9/8 7 y y 3,535,884 10/1970 Chaney 61/465 7 Claims, 2 Drawing Figures ,II'III' rIIII'II DRILLING PLATFORM The invention relates to a floating drilling platform for drilling after and production of natural deposits under the sea.
The new and characteristic which form the basis for the present invention, is the thought that a platform of that type which has a reduced cross-section at the floating line, e.g. semi-submersible state, can be made monolithic of concrete as one or more vertical cells, preferably tube shaped, with a bottom. This very simple construction will, as showed below, offer many advantages compared with the conventional floating platforms.
For a better understanding of the invention it will be described further by means of an example.
FIG. 1 shows a vertical section B B through the platform and FIG. 2 shows a horizontal section A A.
1 is a cell which is terminated under the water surface, 2 is a cell which is terminated above the water surface and 3 is a cell without a bottom which the drill 4 passes through. 5 is the workingor service deck of the platform and 6 is the drilling tower.
The tubes may have varying wall thickness and diameter. It is, however, an advantage if the variations are small, since the platform in that case can be made by means of slip forms.
It will immediately appear from the figure that it is easy to achieve the center of gravity to be below the center of buoyancy and there are thus no problems at tached to the stability.
The cells may during the drilling be filled withair,
sand or water. There must always be some air present for buoyancy, while sand is an excellent ballast material. Other solid ballast material, of course, can be used. Water will be the natural medium for trimming.
The cells may also be used for tanks, e.g. for oil storage or as a dumping place for polluted materials.
A series of advantages are achieved in that the drilling takes place through a tube. The work will not be hindered by waves or ice. Such a solution means a big advantage, especially for the divers, since their work often becomes restricted due to the difficulties in getting up and down through the wave area. The tube will also beable to collect spill of oil, and prevent the oil from spreading in the sea.
As it appears from the figure, the platform will extend downwards much deeper than other floating platforms. The figure shows a platform which has a sub structure nearly double the height of the drilling tower,
e.g. a sub structure of 70 80 metres. This is 3 4 times the normal depth of a sub structure of a semisubmersible platform. At these depths the sea is practically calm irrespective of the waves on the surfaceThe large weight of the concrete, the reduced cross-section of the platform at the floating line and possibly ballast of sand all adds to the stability, and the result is a platform whichv lies far more steady in the sea than other floating platforms. In contrast to the existing platforms, a platform according to the invention will thus not need to interrupt the work due to bad weather. This is of large importance in so called wild-cat"-drilling, and absolutely of vital improtance for production. None of the existing floating platforms may be used for production, namely because production must go on continously irrespective of the weather. The weight and stability of the platform is also necessary, if it is to be provided with industrial plants, fishplate arrangements etc. The service deck can thus be provided with industrial equipment, quay installations, and the like.
The large sub structure of the platform is also advantageous for conventional anchoring, since the anchors may be fastened far down and thus obtain a greater effect since the chain or the wire remains lying more horizontally. Dynamic anchoring may be employed.
The cell formed concrete structure is in itself particularly favourable. The construction can take up very large pressure-forces, since buckling problems practically do not exist. This is of importance with regard to the large water pressures in question, and with more occasional local stresses, e.g. from ice.
A platform according to the invention offers no production difficulties, since the production can be performed exclusively by means of simple method and modest aids. A natural way is to cast the bottom and a bit of the walls in a dry-dock, tow this out to a deep sea area and thereafter erect the walls by means of slip forms, while the platform gradually sinks down in the water. Alternatively, the platform may be provided with its own propulsion equipment.
Compared with a conventional semi-submersible platform, the platform according to the invention has the following advantages:
a. a simpler manufacture, b. a more robust construction,
c. substantially better stability,
d. no corrosion, i.e., little maintenance,
e. protection for the drilling work,
f. possibilities for collecting spill of oil,
g. cheap storage or oil etc.,
h. probably more favourable with regard to price and building time, i. conventional anchoring becomes more efficient. 'The platform is more difficult to move than other floating platforms. This plays less importance if it operates within a limited geographical area, and is completely without inportance for a production platform.
It will immediately be understood that the design of the invention which is shown on the drawing and described above, is only meant to illustrate the inventive thought, and that this may be varied in a series of ways within the idea of the invention.
1 claim:
1. In a floating platform for drilling after natural deposits beneath the floor of the sea having a reduced cross section at the sea surface, a service deck above the sea surface and a sub structure extending downwardly below the sea surface, the improvement wherein said platform is monolithic and mobile, and comprises a plurality of contiguous vertical cells of concrete at least one of the cells lengthened to above sea level to form a support for a service deck, a service deck permanently fixed to said platform, the nonlengthened cells located a substantial distance below the deck section so that the top of said non-lengthened cell or cells is at a substantial depth below the surface of the sea, a drilling structure on said service deck, a bottom deck closing the bottom of said vertical cells and adapted to be positioned deep below the sea sur- 7 face and above the floor of the sea, the whole structure being constructed and arranged such that the center of gravity of said platform is below the center of buoyancy thereof.
2. An improved platform according to claim 1 further including a drill extending from said service deck down through one of said verticle cells to the sea floor.
3. An improved platform according to claim 1 wherein said sub structure extends at least 70 meters below the surface of the sea.
4. An improved platform according to claim 1 wherein said platform includes a first group of adjacent vertical concrete cells extending from said service deck to said bottom deck and a second group of vertical concrete cells in surrounding adjacency with said first group and extending from said bottom deck upwards to ballast material.

Claims (7)

1. In a floating platform for drilling after natural deposits beneath the floor of the sea having a reduced cross section at the sea surface, a service deck above the sea surface and a sub structure extending downwardly below the sea surface, the improvement wherein said platform is monolithic and mobile, and comprises a plurality of contiguous vertical cells of concrete at least one of the cells lengthened to above sea level to form a support for a service deck, a service deck permanently fixed to said platform, the non-lengthened cells located a substantial distance below the deck section so that the top of said nonlengthened cell or cells is at a substantial depth below the surface of the sea, a drilling structure on said service deck, a bottom deck closing the bottom of said vertical cells and adapted to be positioned Deep below the sea surface and above the floor of the sea, the whole structure being constructed and arranged such that the center of gravity of said platform is below the center of buoyancy thereof.
2. An improved platform according to claim 1 further including a drill extending from said service deck down through one of said verticle cells to the sea floor.
3. An improved platform according to claim 1 wherein said sub structure extends at least 70 meters below the surface of the sea.
4. An improved platform according to claim 1 wherein said platform includes a first group of adjacent vertical concrete cells extending from said service deck to said bottom deck and a second group of vertical concrete cells in surrounding adjacency with said first group and extending from said bottom deck upwards to a point intermediate said service deck and said bottom deck.
5. An improved platform according to claim 1 further including means for introducing natural deposits into at least one of said vertical cells.
6. An improved platform according to claim 1 further including means for introducing waste materials into at least one of said vertical cells.
7. An improved platform according to claim 1 wherein at least one of said vertical cells contains solid ballast material.
US00233879A 1971-03-16 1972-03-13 Drilling platform Expired - Lifetime US3824943A (en)

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FR (1) FR2130518B1 (en)
GB (2) GB1387036A (en)
ZA (1) ZA721805B (en)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3863457A (en) * 1972-06-13 1975-02-04 Selmer As Ing F Submarine foundation and offshore working platform
US4004531A (en) * 1974-05-16 1977-01-25 Texaco Inc. Drilling system for deep water offshore locations
US4112864A (en) * 1976-10-08 1978-09-12 Seatek Corporation Heave stabilization of semi-submersible platforms
US4241685A (en) * 1977-11-22 1980-12-30 Iti Ltd. Self-stabilizing floating tower
US4498412A (en) * 1982-06-08 1985-02-12 Gotaverken Arendal Ab Offshore platform
US4702648A (en) * 1984-04-27 1987-10-27 Jan Stageboe Tension leg platform
US4703709A (en) * 1983-04-21 1987-11-03 Institut Francais Du Petrole Modular system for the offshore production, storage and loading of hydrocarbons
US5983822A (en) * 1998-09-03 1999-11-16 Texaco Inc. Polygon floating offshore structure
US6015245A (en) * 1997-09-08 2000-01-18 Frimm; Fernando C. Semisubmersible offshore vessel
US6230645B1 (en) 1998-09-03 2001-05-15 Texaco Inc. Floating offshore structure containing apertures
US6244347B1 (en) 1999-07-29 2001-06-12 Dril-Quip, Inc. Subsea well drilling and/or completion apparatus
US20080083246A1 (en) * 2006-10-06 2008-04-10 Aker Kvaerner, Inc. Gas Conditioning Method and Apparatus for the Recovery of LPG/NGL(C2+) From LNG
US20080210305A1 (en) * 2004-09-21 2008-09-04 Aker Kvaerner, Inc. Liquified Natural Gas Sump For a Gravity Based Structure
US8540460B2 (en) 2010-10-21 2013-09-24 Vetco Gray Inc. System for supplemental tensioning for enhanced platform design and related methods

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB9106030D0 (en) * 1991-03-21 1991-05-08 Bp Petroleum Dev Ltd Production buoy

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2940266A (en) * 1956-07-30 1960-06-14 Shamrock Drilling Co Method of constructing an offshore well drilling island
US2972973A (en) * 1958-05-06 1961-02-28 Ernest L Thearle Offshore platform
US3154039A (en) * 1962-07-25 1964-10-27 Jersey Prod Res Co Stable floating foundation
US3273526A (en) * 1963-11-15 1966-09-20 Lawrence R Glosten Stable ocean platform
US3360810A (en) * 1964-05-28 1968-01-02 Shell Oil Co Floating reservoir vessel of the displacement type
US3434442A (en) * 1967-04-19 1969-03-25 Mobil Oil Corp Offloading moored production storage unit
US3510892A (en) * 1966-11-30 1970-05-12 Automatisme Cie Gle Floating platform
US3535884A (en) * 1967-06-30 1970-10-27 Sun Oil Co Offshore drilling and production structure
US3572043A (en) * 1969-02-24 1971-03-23 Ernest A Clara Underwater structure
US3681923A (en) * 1969-04-28 1972-08-08 Winfield H Hyde Method and apparatus for controlling subnatant oil seepage
US3708987A (en) * 1971-07-23 1973-01-09 J Roulet Concrete reservoir for underwater use

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2940266A (en) * 1956-07-30 1960-06-14 Shamrock Drilling Co Method of constructing an offshore well drilling island
US2972973A (en) * 1958-05-06 1961-02-28 Ernest L Thearle Offshore platform
US3154039A (en) * 1962-07-25 1964-10-27 Jersey Prod Res Co Stable floating foundation
US3273526A (en) * 1963-11-15 1966-09-20 Lawrence R Glosten Stable ocean platform
US3360810A (en) * 1964-05-28 1968-01-02 Shell Oil Co Floating reservoir vessel of the displacement type
US3510892A (en) * 1966-11-30 1970-05-12 Automatisme Cie Gle Floating platform
US3434442A (en) * 1967-04-19 1969-03-25 Mobil Oil Corp Offloading moored production storage unit
US3535884A (en) * 1967-06-30 1970-10-27 Sun Oil Co Offshore drilling and production structure
US3572043A (en) * 1969-02-24 1971-03-23 Ernest A Clara Underwater structure
US3681923A (en) * 1969-04-28 1972-08-08 Winfield H Hyde Method and apparatus for controlling subnatant oil seepage
US3708987A (en) * 1971-07-23 1973-01-09 J Roulet Concrete reservoir for underwater use

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
The Oil and Gas Journal of Sept. 14, 1970, pages 60, 61. *

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3863457A (en) * 1972-06-13 1975-02-04 Selmer As Ing F Submarine foundation and offshore working platform
US4004531A (en) * 1974-05-16 1977-01-25 Texaco Inc. Drilling system for deep water offshore locations
US4112864A (en) * 1976-10-08 1978-09-12 Seatek Corporation Heave stabilization of semi-submersible platforms
US4241685A (en) * 1977-11-22 1980-12-30 Iti Ltd. Self-stabilizing floating tower
US4498412A (en) * 1982-06-08 1985-02-12 Gotaverken Arendal Ab Offshore platform
US4703709A (en) * 1983-04-21 1987-11-03 Institut Francais Du Petrole Modular system for the offshore production, storage and loading of hydrocarbons
US4766836A (en) * 1983-04-21 1988-08-30 Institut Francais Du Petrole Modular system for the offshore production, storage and loading of hydrocarbons
US4702648A (en) * 1984-04-27 1987-10-27 Jan Stageboe Tension leg platform
US6015245A (en) * 1997-09-08 2000-01-18 Frimm; Fernando C. Semisubmersible offshore vessel
US5983822A (en) * 1998-09-03 1999-11-16 Texaco Inc. Polygon floating offshore structure
US6230645B1 (en) 1998-09-03 2001-05-15 Texaco Inc. Floating offshore structure containing apertures
US6244347B1 (en) 1999-07-29 2001-06-12 Dril-Quip, Inc. Subsea well drilling and/or completion apparatus
US20080210305A1 (en) * 2004-09-21 2008-09-04 Aker Kvaerner, Inc. Liquified Natural Gas Sump For a Gravity Based Structure
US20080083246A1 (en) * 2006-10-06 2008-04-10 Aker Kvaerner, Inc. Gas Conditioning Method and Apparatus for the Recovery of LPG/NGL(C2+) From LNG
US8499581B2 (en) 2006-10-06 2013-08-06 Ihi E&C International Corporation Gas conditioning method and apparatus for the recovery of LPG/NGL(C2+) from LNG
US8540460B2 (en) 2010-10-21 2013-09-24 Vetco Gray Inc. System for supplemental tensioning for enhanced platform design and related methods

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GB1387037A (en) 1975-03-12
ZA721805B (en) 1972-12-27
FR2130518A1 (en) 1972-11-03
BR7201533D0 (en) 1973-05-10
FR2130518B1 (en) 1975-04-25
GB1387036A (en) 1975-03-12

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