Hydraulic and earth engineering – Marine structure or fabrication thereof – Floatable to site and supported by marine floor
Reexamination Certificate
1999-08-17
2001-08-21
Bagnell, David (Department: 3673)
Hydraulic and earth engineering
Marine structure or fabrication thereof
Floatable to site and supported by marine floor
C405S195100, C405S204000, C405S205000, C405S209000, C114S260000, C114S267000, C114S044000, C414S138100
Reexamination Certificate
active
06276875
ABSTRACT:
This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/NO97/00343 which has an International filing date of Dec. 17, 1997, which designated the United States of America.
FIELD OF THE INVENTION
The invention concerns a method and a transporter for installation or removal of a jacket for an offshore platform.
BACKGROUND OF THE INVENTION
The installation of offshore platforms is relevant in connection with the development of oil and gas fields at sea.
The removal of offshore platforms, consisting of deck and jacket, is a field which will become more important in the coming years, with the decommissioning of a number of offshore platforms.
Offshore platforms can be removed by being split up into smaller parts, for example by means of cutting torches or blasting, whereupon each of these smaller parts can be lifted aboard a barge or a ship and transported away. Regardless of how the splitting up is carried out, however, the costs associated with the breaking up and subsequent transport in smaller parts are substantial.
Thus, it is a wish to split up a platform which has to be removed into the fewest possible parts, in which case a natural division is to divide it into deck and jacket, each of which is removed separately. In the case of small platforms with low weight this is relatively problem-free, while in the case of large and heavy platforms it entails lifting with extremely large and expensive crane vessels, if it is even possible at all within the scope of what can be implemented in practice.
Norwegian patent application no. 91 0358 describes a method for removal of a platform jacket, wherein a device in the form of a ballastable hull with a deck which is arranged to receive the jacket is rotated into an approximately vertical position in which the deck is located parallel to the platform jacket. The platform jacket is secured to the deck and released from the seabed, whereupon the hull is rotated by means of ballasting to a position where the deck and the jacket arc located horizontally in the water. The device has a U-shaped cross section, and in addition to the deck comprises two long sides arranged at the side of the deck. With the method and the device according to Norwegian patent application no. 91 0358 it is thereby possible to remove a platform jacket from the seabed. The described method and device do not, however, solve the whole problem of removing a platform jacket, since during the transfer of the jacket from the device to a quay or a barge the same problem again arises as to how to move such a heavy structure without dividing it up into smaller parts.
SUMMARY OF THE INVENTION
The object of the invention is to provide a method and a transporter for removal of a jacket for an offshore platform, with subsequent transfer of the jacket to a receiver.
The object is further to provide a transporter which will also be able to be used for removal of a platform deck from a jacket, and transport of other heavy objects at sea.
A further object is to be able to use the same transporter for installation of a jacket for an offshore platform, and installation of a deck on the jacket.
The second object is achieved with a transporter of the type mentioned in the introduction, which, is also characterized by the features which are stated in the claims in the applicant's copending submitted Norwegian patent applications, Nos. 973562 and 973563.
The third object is achieved by employing a transporter according to the invention with a method which corresponds to the method according to the invention, but where the actions are performed conversely and the steps are performed in the reverse order.
The method according to the invention comprises the following steps:
a) an oblong ballastable transporter is rotated by means of ballasting from a position where a longitudinal underside of the transporter is lying horizontally in the water to a position where the transporter's underside is located beside an outer side of the jacket,
b) the jacket is attached to a sliding saddle which is provided in the transporter and is movable in the transporter's longitudinal direction,
c) the jacket is released from the seabed,
d) the transporter with the jacket is rotated by means of ballasting to a position where the transporter's underside and the jacket are located substantially horizontally in the water,
e) the transporter is moved to a receiver for the jacket, and
f) the sliding saddle with the jacket are moved from the transporter to the receiver.
The transporter according to the invention includes an oblong, ballastable structure, rotatable across the longitudinal direction by means of ballasting, with a sliding saddle which is movable in the longitudinal direction and adapted for securing of the jacket, thus enabling the jacket to be moved in relation to the transporter by means of the sliding saddle, after being secured in the sliding saddle and released from the seabed.
The transporter according to the invention makes it possible to remove a platform jacket from the seabed, transport the jacket to a quay or possibly a barge for further transport, and transfer the jacket to the quay or the barge without the use of cranes.
The actual movement of the transporter will be conducted by tugs. The positioning of the transporter may be carried out by winches which can vary the length of wires between the transporter and the platform jacket or another fixed point.
Thus by means of the invention a rational and economically advantageous removal of a platform jacket is provided.
Further features and advantages will be seen in the detailed description.
The transporter according to the invention may also be employed in the installation of a jacket for an offshore platform. In the installation of a jacket a method is employed which corresponds to the method according to the invention, but where the steps are performed in the reverse order and the actions which are performed within each step are performed conversely. This is a clear variant of the method according to the invention, and will not be explained in detail. It should be understood, however, that the inventive concept also covers this alternative.
Further scope of the applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 2379685 (1945-07-01), Crandall
patent: 3054267 (1962-09-01), Alcorn et al.
patent: 3097495 (1963-07-01), Laborde et al.
patent: 3621662 (1971-11-01), Starr et al.
patent: 3633369 (1972-01-01), Lawrence
patent: 3736756 (1973-06-01), Lloyd
patent: 3823564 (1974-07-01), Crout et al.
patent: 3859804 (1975-01-01), Koehler et al.
patent: 3878688 (1975-04-01), Purvis
patent: 3987637 (1976-10-01), Koehler
patent: 4086777 (1978-05-01), Lai
patent: 4683832 (1987-08-01), Dysarz
patent: 4690586 (1987-09-01), Oksuzler
patent: 4825791 (1989-05-01), Foster, Jr. et al.
patent: 4874269 (1989-10-01), Dysarz
patent: 4927296 (1990-05-01), Kaldenbach
patent: 5097786 (1992-03-01), Sheffield
patent: 5111764 (1992-05-01), D'Ettorre
patent: 3219968 (1983-12-01), None
patent: 910358 (1991-05-01), None
patent: 9826979 (1998-06-01), None
patent: 9906270 (1999-02-01), None
Bull Haugsøen Per
Gunnar Foss
Bagnell David
Birch & Stewart Kolasch & Birch, LLP
Lee Jong-Suk
Offshore Shuttle AS
LandOfFree
Method and transporter for installation or removal of a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and transporter for installation or removal of a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and transporter for installation or removal of a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2534772