GB2367534A - Surface accessed offshore production facility - Google Patents

Surface accessed offshore production facility Download PDF

Info

Publication number
GB2367534A
GB2367534A GB0024149A GB0024149A GB2367534A GB 2367534 A GB2367534 A GB 2367534A GB 0024149 A GB0024149 A GB 0024149A GB 0024149 A GB0024149 A GB 0024149A GB 2367534 A GB2367534 A GB 2367534A
Authority
GB
United Kingdom
Prior art keywords
equipment module
seabed
production facility
offshore production
module
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB0024149A
Other versions
GB0024149D0 (en
Inventor
David Bone
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ocean Technologies Ltd
Original Assignee
Ocean Technologies Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ocean Technologies Ltd filed Critical Ocean Technologies Ltd
Priority to GB0024149A priority Critical patent/GB2367534A/en
Publication of GB0024149D0 publication Critical patent/GB0024149D0/en
Publication of GB2367534A publication Critical patent/GB2367534A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B17/02—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto
    • E02B17/025—Reinforced concrete structures
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B2017/0056—Platforms with supporting legs
    • E02B2017/0065—Monopile structures
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B2017/0056—Platforms with supporting legs
    • E02B2017/0073—Details of sea bottom engaging footing
    • E02B2017/0078—Suction piles, suction cans
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02B—HYDRAULIC ENGINEERING
    • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
    • E02B2017/0056—Platforms with supporting legs
    • E02B2017/0073—Details of sea bottom engaging footing
    • E02B2017/0086—Large footings connecting several legs or serving as a reservoir for the storage of oil or gas
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D2250/00—Production methods
    • E02D2250/0053—Production methods using suction or vacuum techniques

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Earth Drilling (AREA)

Abstract

A surface accessed offshore production facility comprises a watertight equipment module 1 located at or near the seabed, an access shaft 2 which extends vertically from the module to a point above sea level and ballast/suction caissons 3 arranged around the periphery of the module. The ballast/suction caissons are attached to the module by interconnecting structural support 4. The equipment module has a sleeve fitted into its base which is sealed during installation but which provides a route for drilling into the seabed through the equipment module when the facility is operational.

Description

SURFACE ACCESSED OFFSHORE PRODUCTION FACILITY This invention relates to a low cost shallow water offshore production facility.
Offshore production facilities for shallow water generally comprise either various types of structure supporting a platform some distance above mean sea level or alternatively complex arrangements of specialised equipment located on the seabed.
Both systems are however expensive. Moreover the latter system will not generally permit the processing of hydrocarbons prior to onward transmission to shore of all offshore processing facilities.
Another disadvantage of the former system is that the seabed may be soft, comprised of weak soils, and/or uneven, thereby making it difficult to reliably install the platform.
A further disadvantage is the previous use of large structure support foundations which impose large loads on the sea bed soils due to horizontal drag loading.
We have now devised a surface accessed offshore production facility and a means of installing and supporting the same, which alleviates the above problems.
According to the present invention there is provided a surface accessed offshore production facility comprising a watertight equipment module located at or near the seabed, with access to the surface via a shaft which extends vertically from the equipment module to a point above highest mean sea level, associated ballast/suction caissons peripherally arranged and interconnecting structural support.
The equipment module has a sleeve fitted into its base structure which is normally sealed during installation but which is arranged to provide a route for drilling into the seabed through the equipment module whilst maintaining watertight integrity.
The associated ballast/suction caissons comprise discrete chambers, normally cylindrical. By controlling the water level within these chambers the facility can be raised and lowered for installation and removal.
The ballast/suction caisson also serves the purpose of securing the structure to the seabed following installation. Once the structure has been ballasted to the seabed and has partially penetrated, the pressure within the caissons is reduced by pumping to create an additional downward load to further penetrate each caisson into the seabed.
The ballast/suction caissons can be inserted to a controllable depth facilitating installation in uneven seabed conditions. Also, they experience far less severe drag loading than a large gravity base support, thus they impose less load on the sea bed soils and allow installation in a wide range of sea bed conditions.
A specific embodiment of the invention will now be described by way of example only and with reference to the accompanying drawing in which: Figure 1 shows in vertical cross section the surface accessed template on location.
Referring to the drawing the facility comprises a reinforced concrete structure with a watertight equipment module 1. The construction material could equally well be ferrous cement or any other suitable material. The watertight equipment module 1 may have a series of internal compartments (not shown) for use in operations. The watertight equipment module 1 is open to the atmosphere via a shaft 2 to the surface.
A plurality of ballast/suction caissons 3 (three in this example) is secured to the watertight equipment module 1 through interconnecting structural support 4.
The ballast/suction caissons 3 can be used to provide additional buoyancy during flotation and ballasted to aid installation. The caissons 3 may be compartmentalised (not shown) with the upper portion dedicated to the provision of flotation by being air-filled. The lower portion can also be used to provide flotation by displacing the water with compressed air. Control of the water level within these caissons 3 provides the necessary buoyancy so that the facility can be raised and lowered for installation and removal. On installation the ballast/suction caissons 3 are pumped out to provide suction to the seabed.
The shaft 2 extending above the surface may be fitted with a heli-deck 5 or boat landing 6 or both.

Claims (2)

  1. CLAIMS 1. According to the present invention there is provided a surface accessed offshore production facility comprising a watertight equipment module located at or near the seabed, with access to the surface via a shaft which extends vertically from the equipment module to a point above highest mean sea level, associated ballast/suction caissons peripherally arranged and interconnecting structural support, the equipment module having a sleeve fitted into its base structure which is normally sealed during installation but which is arranged to provide a route for drilling into the seabed through the equipment module whilst maintaining watertight integrity.
  2. 2. A surface accessed offshore production facility substantially as herein described and illustrated in the accompanying drawings.
GB0024149A 2000-10-03 2000-10-03 Surface accessed offshore production facility Withdrawn GB2367534A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0024149A GB2367534A (en) 2000-10-03 2000-10-03 Surface accessed offshore production facility

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0024149A GB2367534A (en) 2000-10-03 2000-10-03 Surface accessed offshore production facility

Publications (2)

Publication Number Publication Date
GB0024149D0 GB0024149D0 (en) 2000-11-15
GB2367534A true GB2367534A (en) 2002-04-10

Family

ID=9900556

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0024149A Withdrawn GB2367534A (en) 2000-10-03 2000-10-03 Surface accessed offshore production facility

Country Status (1)

Country Link
GB (1) GB2367534A (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2295411A (en) * 1994-11-25 1996-05-29 Brookmex Ltd Surface Accessed Offshore Production Facility
WO1999051821A1 (en) * 1998-04-02 1999-10-14 Suction Pile Technology B.V. Marine structure

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2295411A (en) * 1994-11-25 1996-05-29 Brookmex Ltd Surface Accessed Offshore Production Facility
WO1999051821A1 (en) * 1998-04-02 1999-10-14 Suction Pile Technology B.V. Marine structure

Also Published As

Publication number Publication date
GB0024149D0 (en) 2000-11-15

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Legal Events

Date Code Title Description
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
732E Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977)
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)