US 8,474,539 B2 · Pull tube sleeve stress joint for floating offshore structure

Abstract

The present disclosure provides an improved design for a pull tube sleeved stress joint and associated pull tube for managing stresses on a catenary riser for a floating offshore structure. The pull tube sleeve stress joint includes at least one sleeve surrounding a length of the pull tube with an annular gap between the sleeve and pull tube and a link ring therebetween. For embodiments having a plurality of sleeves, a first sleeve can be spaced by an annular first gap from the pull tube and coupled thereto with a first ring between the pull tube and the first sleeve, and a second sleeve can be spaced by an annular second gap from the first sleeve and coupled thereto with a second ring between the first sleeve and the second sleeve. Both pull tube and sleeves can be made with regular pipe segments welded together with regular girth welds.

Claims19

Dependent claims

A system for supporting a catenary riser coupled to an offshore structure, comprising:

a pull tube having one end disposed downward from the offshore structure and an upper portion distal from the one end fixedly coupled to the offshore structure at a first location, the pull tube having one or more segments;
a stress joint middle segment having an outer diameter and an inner diameter defining a passageway for the catenary riser therein, the stress joint middle segment being coupled to one or more segments of the pull tube;
a first sleeve disposed around a length of the stress joint middle segment, the first sleeve having an outer diameter and an inner diameter, the sleeve inner diameter and the stress joint middle segment outer diameter defining a first annular gap therebetween;
and
a sleeve guide coupled to the offshore structure at a second location different from the first location and at least partially surrounding a periphery of the first sleeve,
wherein the combination of the pull tube portion fixedly coupled to the offshore structure at the first location and the sleeve guide coupled to the offshore structure at the second location maintains the position of the pull tube relative to the offshore structure at such locations during usage.

3 more elements

A pull tube sleeved stress joint assembly for a pull tube on a floating offshore structure, comprising:

a sleeve guide coupled to the offshore structure,
a stress joint middle segment having an outer diameter and an inner diameter defining a passageway for a catenary riser therein, the stress joint middle segment rigidly coupled to one or more segments of the pull tube, the pull tube having one end disposed downward from the offshore structure and an upper portion distal from the one end fixedly coupled to the offshore structure at a first location;
and
a first sleeve coupled to the stress joint middle segment, the first sleeve having an outer diameter and an inner diameter, the sleeve inner diameter and the stress joint middle segment outer diameter defining a first annular gap therebetween, the sleeve being coupled to the offshore structure at a second location different from the first location,
wherein the combination of the pull tube portion fixedly coupled to the offshore structure at the first location and the sleeve guide coupled to the offshore structure at the second location maintains the position of the pull tube relative to the offshore structure at such locations during usage.

2 more elements

Dependencies are inferred from the claim text.

Pull tube sleeve stress joint for floating offshore structure

Life of this patent

Pull tube sleeve stress joint for floating offshore structure

Life of this patent

Abstract

Claims19