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.
Patent No.:
Date of Patent:
Dec. 23, 1980
Filed:
Feb. 21, 1979
Donald W Dareing, Houston, TX (US);
Conoco, Inc., Ponca City, OK (US);
Abstract
A downhole riser assembly includes a tubular casing embedded in the ocean floor, said casing having a constant internal diameter and an upper end extending above said ocean floor. A tubular riser pipe is disposed in the casing and has an upper end connected to a floating vessel which may be a tension leg platform. The casing and riser are rigidly connected at a considerable distance below the ocean floor, said distance being on the order of 100 feet. When the floating structure is laterally displaced from a position directly above the casing, the riser pipe contacts the upper end of the casing. This contact limits the lateral deflection of the riser at the ocean floor and thereby limits the stresses in the riser. The distance between the upper end of the casing and the downhole connection between the casing and the riser, and the diameter of the casing are such that the riser has a rotational stiffness, adjacent the upper end of the casing, within a range such that both a maximum design maximum stress and a maximum design bottom slope of said riser are not exceeded when said riser is subjected to maximum design loading conditions. An alternative embodiment of the present invention provides a lateral support means for connecting the riser and the casing adjacent the upper end of the casing for restricting lateral movement of the riser.