US3681928A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for carrying out underwater well operations
Assignee: PIET E HOEKENGA
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Filing: 1970-09-15
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Granted: 1972-08-08
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Expires: 1990-09-15
Abstract
Abstract Method and apparatus for carrying out operations with respect to an underwater well wherein a cable is secured between the well and a platform mounted on a floating vessel over the well site. The platform is mounted for vertical movement relative to the vessel and is continuously biased in an upward direction during said relative movement to maintain the drill pipe under tension and compensate for up and down movement of the vessel.
Inventors
- 👤 Leonardus M J Vincken
- 👤 Paul F Agerbeek
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:42
CPC Classifications
E; E21; E21B; E21B19/00; E21B19/08; E21B19/09
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
231 words
A method of carrying out operations on a well having a wellhead positioned under the surface of a body of water, comprising the steps of: arranging a platform on a floating vessel such that the platform is moveable at least in a substantially vertical direction with respect to the vessel; positioning the vessel above the wellhead; securing one end of each of a plurality of flexible cables to at least one fixed point below the surface of the body of water; securing the opposite end of each of the cables to winch means operatively connected to the platform; applying between the platform and the vessel a substantially constant force upwardly directed with respect to the platform and of magnitude sufficient to move the platform and any equipment thereon upwardly with respect to the vessel; after securing the cables to the fixed point, actuating the winch means to adjust the length of the cables to a length selected to maintain the platform at a selected distance from the bottom of the body of water; the selected distance being one from which the platform is free to move vertically both upwardly and downwardly with respect to the vessel; tensioning the cables to prevent upward movement of the platform with respect to the vessel under the applied substantially constant force when the vessel is at rest; and carrying out underwater operations from the platform.
Claim 2
Independent Claim
231 words
A method of carrying out operations on a well having a wellhead positioned under the surface of a body of water, comprising the steps of: arranging a platform on a floating vessel such that the platform is moveable at least in a substantially vertical direction with respect to the vessel; positioning the vessel above the wellhead; securing one end of each of a plurality of flexible cables to at least one fixed point below the surface of the body of water; securing the opposite end of each of the cables to winch means operatively connected to the platform; applying between the platform and the vessel a substantially constant force upwardly directed with respect to the platform and of magnitude sufficient to move the platform and any equipment thereon upwardly with respect to the vessel; after securing the cables to the fixed point, actuating the winch means to adjust the length of the cables to a length selected to maintain the platform at a selected distance from the bottom of the body of water; the selected distance being one from which the platform is free to move vertically both upwardly and downwardly with respect to the vessel; tensioning the cables to prevent upward movement of the platform with respect to the vessel under the applied substantially constant force when the vessel is at rest; and carrying out underwater operations from the platform.
Claim 3
Dependent Claim
24 words
The method according to claim 1, wherein the force between the platform and the vessel is created by means of at least one weight.
Claim 4
Dependent Claim
25 words
The method according to claim 1, wherein the force between the platform and the vessel is created by a piston arranged in a fluid cylinder.
Claim 5
Independent Claim
125 words
An apparatus for carrying out operations at offshore well locations comprising: a base fixedly positioned adjacent the well below the surface of the body of water; a floating vessel, a work platform operatively connected to said floating vessel so that said work platform is vertically moveable with respect to said floating vessel, means for applying vertically directed force between said work platform and said floating vessel, a plurality of flexible cables operatively connected between said work platform and said base, cable-engagIng means on said work platform for engaging each of said cables, and wench means mounted on the platform, one winch means operatively associated with each of said cable-engaging means for adjusting the length of said cables and thereby adjusting the tension in said cables.
Claim 6
Independent Claim
125 words
An apparatus for carrying out operations at offshore well locations comprising: a base fixedly positioned adjacent the well below the surface of the body of water; a floating vessel, a work platform operatively connected to said floating vessel so that said work platform is vertically moveable with respect to said floating vessel, means for applying vertically directed force between said work platform and said floating vessel, a plurality of flexible cables operatively connected between said work platform and said base, cable-engagIng means on said work platform for engaging each of said cables, and wench means mounted on the platform, one winch means operatively associated with each of said cable-engaging means for adjusting the length of said cables and thereby adjusting the tension in said cables.
Claim 7
Dependent Claim
66 words
The structure as claimed in claim 4, in which the means for applying a vertically directed force to the platform comprises at least one cable having one end secured to the platform and the other end to a weight, the cable being led over a pulley which is arranged on the structure at a level above the highest position of the platform relatively to the vessel.
Claim 8
Dependent Claim
59 words
The structure as claimed in claim 4, in which the means for applying an upwardly directed force to the platform comprises at least one cylinder arranged on the structure, a piston arranged in the cylinder, a connection between the piston and the platform, a pressure source communicating with the cylinder, and means for controlling the pressure in the cylinder.
Claim 9
Dependent Claim
32 words
The structure as claimed in claim 6 in which a system is present for keeping the pressure in the cylinder substantially constant in all positions of the platform relatively to the vessel.
Claim 10
Dependent Claim
50 words
The structure as claimed in claim 7, in which the system for keeping the pressure in the cylinder constant comprises a pressure tank containing gas and having a volume which is large relative to the volume of the cylinder, and a fluid connection between the cylinder and the pressure tank.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |