US3785445A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Combined riser tensioner and drill string heave compensator
Assignee: Individual
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Filing: 1972-05-01
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Granted: 1974-01-15
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Expires: 1992-05-01
Abstract
Abstract The rod end of a heave compensator is hydraulically coupled to the head end of a riser tensioner used on a floating drilling vessel. The rod end of the riser tensioner is pressurized an amount sufficient to provide not only a tension on the riser, but in addition a lifting force on the drill string. The hydraulic fluid displaced between the heave compensator and riser tensioner accommodates rotation of the vessel due to wave action. The riser tensioner is isolated from the heave compensator and coupled to a pressurized hydraulic supply whenever the heave compensator is disconnected from the drill string.
Inventors
- 👤 J Scozzafava
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:26
CPC Classifications
E; E21; E21B; E21B7/00; E21B7/12; E21B7/128; E21B19/00; E21B19/08; E21B19/09
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
246 words
A combined riser tensioner and drill string heave compensator for a floating drilling vessel having a drilling derrick, a drill string, means for supporting the drill string, means for positioning tHe drill string supporting means, a riser, and means for supporting the riser, comprising: drill string heave compensator means coupled to said drill string supporting means for maintaining a substantially constant lifting force on said drill string regardless of movements of the vessel, said drill string heave compensator means including at least one cylinder, piston and piston rod, riser tensioning means coupled to said riser supporting means for maintaining a substantially constant lifting force on said riser regardless of movements of the vessel, said riser tensioning means including at least one cylinder, piston and piston rod, means for pressurizing hydraulic fluid in said riser tensioning cylinder an amount sufficient to tension the riser and support a predetermined part of the weight of the drill string, means for hydraulically interconnecting said heave compensating cylinder with said riser tensioning cylinder for passing said pressurized hydraulic fluid therebetween to continue said support of the drill string during movement of said drilling vessel, means for isolating said riser tensioning cylinder from said heave compensating cylinder when said drill string supporting means is disconnected from said heave compensator, and means for compensating said riser tensioning cylinder for pressure changes due to the loss of the weight of the drill string when said heave compensating cylinder and riser tensioning cylinder are disconnected.
Claim 2
Dependent Claim
246 words
A combined riser tensioner and drill string heave compensator for a floating drilling vessel having a drilling derrick, a drill string, means for supporting the drill string, means for positioning tHe drill string supporting means, a riser, and means for supporting the riser, comprising: drill string heave compensator means coupled to said drill string supporting means for maintaining a substantially constant lifting force on said drill string regardless of movements of the vessel, said drill string heave compensator means including at least one cylinder, piston and piston rod, riser tensioning means coupled to said riser supporting means for maintaining a substantially constant lifting force on said riser regardless of movements of the vessel, said riser tensioning means including at least one cylinder, piston and piston rod, means for pressurizing hydraulic fluid in said riser tensioning cylinder an amount sufficient to tension the riser and support a predetermined part of the weight of the drill string, means for hydraulically interconnecting said heave compensating cylinder with said riser tensioning cylinder for passing said pressurized hydraulic fluid therebetween to continue said support of the drill string during movement of said drilling vessel, means for isolating said riser tensioning cylinder from said heave compensating cylinder when said drill string supporting means is disconnected from said heave compensator, and means for compensating said riser tensioning cylinder for pressure changes due to the loss of the weight of the drill string when said heave compensating cylinder and riser tensioning cylinder are disconnected.
Claim 3
Dependent Claim
23 words
The combination of claim 1, said riser tensioning means including a plurality of cylinders, pistons and piston rods equidistantly spaced around said riser.
Claim 4
Dependent Claim
47 words
The combination of claim 1, said riser tensioning cylinder compensating means including means for coupling to the head end of the riser tensioning cylinder an independent hydraulic fluid supply of a pressure equal to the pressure in the heave compensating cylinder prior to disconnecting the drill string.
Claim 5
Dependent Claim
65 words
The combination of claim 1, said means for pressurizing said rod end of said riser tensioning cylinder including a high pressure air supply, said means for counterbalancing the excess pressure acting on the riser tensioning piston due to loss of weight of the drill string including a lower pressure air supply, and hydraulic accumulators coupled to said gas supplies and to said riser tensioning cylinder.
Claim 6
Dependent Claim
105 words
A floating drilling platform in a body of water, a drilling string, a riser for the drilling string anchored at an underwater well site and extending out of the water, fluid-operated riser tensioning means connected to the riser and having a hydraulic expansion chamber varying in size with rise and fall of the platform, hydraulic heave compensating means for supporting the drilling string having a pressure chamber varying inversely in size with rise and fall of the platform as compared to said expansion chamber, means selectively hydraulically interconnecting said chambers whereby the vertical position of said drilling string is held stationary relative to said riser.
Claim 7
Dependent Claim
105 words
A floating drilling platform in a body of water, a drilling string, a riser for the drilling string anchored at an underwater well site and extending out of the water, fluid-operated riser tensioning means connected to the riser and having a hydraulic expansion chamber varying in size with rise and fall of the platform, hydraulic heave compensating means for supporting the drilling string having a pressure chamber varying inversely in size with rise and fall of the platform as compared to said expansion chamber, means selectively hydraulically interconnecting said chambers whereby the vertical position of said drilling string is held stationary relative to said riser.
Claim 8
Dependent Claim
38 words
The combination of claim 5, said fluid-operated riser tensioning means including means for disconnecting said hydraulic-interconnection between said chambers, and means for compensating the riser tensioning means for the lost weight of the drilling string during said disconnection.
Claim 9
Dependent Claim
125 words
In combination: a floating drilling platform, first and second vertical telescopic force applying means carried on the platform for respectively supporting a suspended drilling string and tensioning the riser for the drilling string while compensating by their telescopic action for the rise and fall of the platform relative to the drilling string and riser, third means for transferring the force exerted to support the drilling string by the first means as a load for the second means in addition to the riser tensioning load on the latter, fourth means for selectively deactivating said first means, and fifth means for maintaining the same upward effective forCe exerted by the second means to tension the riser while said first means is deactivated as when it is active.
Claim 10
Dependent Claim
125 words
In combination: a floating drilling platform, first and second vertical telescopic force applying means carried on the platform for respectively supporting a suspended drilling string and tensioning the riser for the drilling string while compensating by their telescopic action for the rise and fall of the platform relative to the drilling string and riser, third means for transferring the force exerted to support the drilling string by the first means as a load for the second means in addition to the riser tensioning load on the latter, fourth means for selectively deactivating said first means, and fifth means for maintaining the same upward effective forCe exerted by the second means to tension the riser while said first means is deactivated as when it is active.
Claim 11
Independent Claim
152 words
The method of compensating for vertical movements of a drilling platform floating in a deep body of water while supporting a drilling string and tensioning a riser for the drilling string to prevent buckling, said riser being anchored at an underwater well site and extending to the surface of the water, the steps of constantly tensioning the riser by an upward force exerted by fluid pressure great enough to also support the downward force of the drilling string when applied in direct opposition to said upward force, and hydraulically transferring said downward force into such direct opposition by means of a pressure chamber pressurized by downward pull of the drilling string and hydraulically connected to an expansion chamber whose pressure opposes said upward force, and keeping the collective volumes of said chambers constant during rise and fall of the platform whereby said drilling string is held vertically stationary relative to said riser.
Claim 12
Independent Claim
152 words
The method of compensating for vertical movements of a drilling platform floating in a deep body of water while supporting a drilling string and tensioning a riser for the drilling string to prevent buckling, said riser being anchored at an underwater well site and extending to the surface of the water, the steps of constantly tensioning the riser by an upward force exerted by fluid pressure great enough to also support the downward force of the drilling string when applied in direct opposition to said upward force, and hydraulically transferring said downward force into such direct opposition by means of a pressure chamber pressurized by downward pull of the drilling string and hydraulically connected to an expansion chamber whose pressure opposes said upward force, and keeping the collective volumes of said chambers constant during rise and fall of the platform whereby said drilling string is held vertically stationary relative to said riser.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-14 | 1977-07-16 | 1978-01-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-14 | 1981-07-16 | 1982-01-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-14 | 1985-07-16 | 1986-01-15 | $7700.00 | Window Closed / Lapsed |