Subsea 7 Do Brasil Servicos Ltda

Gustavo Queiroz Hepner

Luiz Carlos De Lemos Junior

Andre Ramiro Amorim

Daniel Karunakaran

Luiz Carlos De Lemos JÚNIOR

A subsea catenary riser comprises a rigid riser pipe that is suspended from a floating support on the surface and extends through a sagbend to the seabed. A hang-off interface allows rotation or pivoting of the riser pipe relative to the support about mutually orthogonal horizontal axes. A subsea buoy is positioned on the riser pipe above the sagbend. The buoy applies buoyant upthrust force to the riser pipe via an attachment interface that allows rotation or pivoting of the riser pipe relative to the buoy about mutually orthogonal horizontal axes. In response to movement of the support, the riser pipe deflects with S-shaped curvature to vary the inclination, relative to the buoy, of the portion of the riser pipe to which the buoy is attached. The curvature comprises mutually opposed curves respectively above and below the buoy, joined by a region of inflection that coincides with the buoy.

Subsea risers

A top connection arrangement for a subsea riser comprises a pivot or joint combination disposed between, and fluidly connecting, upper and lower sections of rigid pipe. The pivot combination comprises an upper ball joint about which the upper pipe section is pivotable. A lower joint, being a flexible joint or a tapered stress joint to which the lower pipe section is attached, is fixed to the ball joint in series. A sleeve is fixed to the ball joint and surrounds the upper pipe section to permit limited pivotal movement of that pipe section about the ball joint. The sleeve may seat into the bellmouth of an I- or J-tube of a surface facility or may be omitted if the lower joint is seated in a hang-off formation. A locking mechanism is capable of locking the ball joint and hence preventing pivotal movement of the upper pipe section.

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Katy, TX, United States of America

Gustavo Queiroz Hepner