Wells – Submerged well – Means removably connected to permanent well structure
Reexamination Certificate
1999-06-21
2001-07-17
Bagnell, David (Department: 3672)
Wells
Submerged well
Means removably connected to permanent well structure
C166S350000, C166S241600
Reexamination Certificate
active
06260625
ABSTRACT:
TECHNICAL FIELD
This invention relates to offshore drilling and production platforms, and in particular to devices for guiding and positioning risers of such platforms.
BACKGROUND ART
In one type of offshore oil or gas well, a riser is connected between a subsea wellhead and a floating drilling and/or production platform. Oftentimes, the subsea wellhead is not in exact alignment with the platform that is used to secure the riser or handle the riser during assembly. Further, the platform may be subject to movement from wave action and the like, while the riser is stationarily held at the wellhead.
It is important that relative movement between the platform and the riser, due to wave action and the like, be constrained to facilitate production and drilling operations and maintain clearance between the riser and other platform equipment. Throughout drilling and production operations, various pieces of equipment must be attached and detached from the riser, and often the riser has work platforms joined thereto which extend outward from the riser. This leaves little clearance between the riser and its surroundings, thus movement of the platform relative to the riser may cause damage to the riser, the equipment and work platforms joined to the riser, and the surrounding platform and platform equipment. Further, relative riser movement complicates the alignment and coupling of equipment which must be attached and detached from the riser.
Centralizing devices of the prior art have maintained only the riser's lateral position relative to the platform. However, it is further desirable to also constrain torsional movement relative to the platform, because it allows more freedom in the design of attached equipment or work platforms. For example, a work platform joined to a riser may be rectangular and fit in a rectangular clearance bounded by platform equipment. Rotation of the platform relative to the riser may cause the work platform to contact and damage its surroundings.
SUMMARY OF THE INVENTION
The present invention is directed to a centralizing device which constrains lateral and torsional movement of a riser relative to the platform; the riser having fins extending outward from its outer diameter. The centralizing device has a frame for mounting to the platform. More than one centralizing roller is mounted to the frame. The centralizing rollers are adjustable radially relative to the riser to bear against the riser and limit its lateral movement relative to the platform. At least a pair of torsional rollers is also mounted to the frame. The torsional rollers are arranged in opposed to each other and are adjustable toward and away from each other. The torsional rollers are angularly and laterally adjustable about an axis of the frame. The torsional rollers may be mounted to a plate that allows translational movement relative to the frame. The plate may be mounted to a second plate that allows rotational movement relative to the frame. The centralizing rollers and the torsional rollers may be mounted on separate levels of the frame.
REFERENCES:
patent: 4053022 (1977-10-01), Mercier
patent: 4395160 (1983-07-01), deJong
patent: 4469181 (1984-09-01), Kellett
patent: 4733991 (1988-03-01), Myers
patent: 4844660 (1989-07-01), Ortemond
patent: 5118221 (1992-06-01), Copple
patent: 5169265 (1992-12-01), Butler et al.
patent: 5479990 (1996-01-01), Peppel
patent: 5950737 (1999-09-01), Chou et al.
1242769(London) Aug. 11, 1971 “Improvements in or Relating to Offshore Drilling Apparatus”.
GB2115858A (UK) Sep. 14, 1983 “Adjustable Conductor Guide Assembly for Subsea Wells and Methods and Tools for Adjustment Thereof”.
Harms Kent
Mican Gilbert
Pelzl Jon
Phan Kim
VanBarneveld Jon
ABB Vetco Gray Inc.
Bagnell David
Bracewell & Patterson L.L.P.
Bradley James E.
Dougherty J
LandOfFree
Apparatus and method for torsional and lateral centralizing... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus and method for torsional and lateral centralizing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus and method for torsional and lateral centralizing... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2507389