The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Jan. 12, 2021

Filed:

Oct. 07, 2019
Applicant:

Subsea 7 Norway As, Stavanger, NO;

Inventor:

Sigbjorn Daasvatn, Hornnes, NO;

Assignee:

Subsea 7 Norway AS, Stavanger, NO;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21B 40/00 (2006.01); E21B 41/00 (2006.01); E21B 43/017 (2006.01); E21B 43/36 (2006.01); E21B 19/00 (2006.01); B63B 21/66 (2006.01); E21B 43/01 (2006.01);
U.S. Cl.
CPC ...
E21B 41/0007 (2013.01); B63B 21/66 (2013.01); E21B 19/002 (2013.01); E21B 43/017 (2013.01); E21B 43/36 (2013.01); E21B 43/0107 (2013.01);
Abstract

A method transports and installs a heavy subsea structure such as a subsea processing center for produced crude oil or natural gas. The method includes controlledly flooding at least one ballast tank attached to or incorporated into the structure to the extent that the structure becomes negatively buoyant at a pre-determined towing depth. The method also includes towing the negatively-buoyant structure at the towing depth by the Controlled Depth Towing Method (CDTM). After towing to the installation location, the method includes further flooding the ballast tank to lower the structure onto the seabed. At the seabed, a fluid transportation pipe of a subsea production installation may be coupled to pipework of the structure.


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