Technip France

Cso Aker Maritime, Inc.

Qi Xu

Phillip Andrew Abbott

James Francis O'Sullivan

John E Halkyard

Michael Y H Luo

Steven Barras

Tao Qi

Jeffery C Measamer

The disclosure provides a semi-submersible offshore platform with columns having an enlarged base on the bottom of each column with pontoons coupled between the columns. The enlarged column base can be at least as high as a height of the pontoon and on at least embodiment can be about 50% of the draft of the platform. The enlarged base can change a current flow shape around the base and columns for lower VIM. An outside corner of the base can be trimmed at an angle. Alternatively, the lower portions of the columns can be extended horizontally outward to form an effectively enlarged base having similar characteristics. In some embodiments, the pontoon volume can be reduced inversely proportional to the base enlargement to have comparable total buoyancy.

Semi-submersible floating structure for vortex-induced motion performance

The disclosure provides an offshore platform and related method, having: a floating structure, a truss assembly coupled to the floating structure, and a heave plate coupled to the truss assembly. The floating structure includes a pontoon adapted to be disposed at least partially below a surface of water in which the offshore platform is disposed; and at least three vertically extending columns coupled to the pontoon, the columns having a larger lateral dimension than the pontoon coupled to the column, creating a pontoon offset portion. The truss assembly includes at least three separated walls of trusses slidably coupled to the columns, each truss wall having at least two vertically disposed truss legs, each truss leg being slidably coupled to a column at the pontoon offset portion independently from a truss leg of an adjacent wall; and cross-bracing between the truss legs of each of the truss walls.

Truss heave plate system for offshore platform

The disclosure provides a tension leg platform ('TLP') with a plurality of buoyant pontoons suitable for highly disturbed seas that can expand the stability of the tension leg platform by extending at least one buoyant pontoon beyond an intersection of two pontoons. In at least one embodiment, the location of the column can be decoupled from the customary end of the pontoon. The tendons can be located at the ends of the pontoons extending beyond the intersection. In some embodiments, such as four-column TLPs, the pontoons can be extended orthogonally relative to an adjacent pontoon. The extending pontoon increases a buoyancy of the pontoon, increases a pitch stability of the TLP, and increases quayside stability. The extended pontoon can be structurally intersected with the adjacent pontoon to strengthen the extended pontoon and reduce the failure mode of such structure.

System for increased floatation and stability on tension leg platform by extended buoyant pontoons

An extendable draft platform, having a deck and buoyancy columns installed in leg wells in the deck for vertical movement from a raised position to a submerged position, includes a connection arrangement for securing the columns to the deck when the columns are in the submerged position. In the connection arrangement, a plurality of first guide elements near the top of each column is engageable by a plurality of complementary second guide elements secured to the deck around each leg well when the column is lowered to its submerged position. A locking mechanism is operable between the columns and the deck when the first guide elements are engaged with the second guide elements. The first and second guide elements may be configured so that the connection between the deck and the columns may be enhanced by over-ballasting the columns and/or by welding the columns to the deck.

Deck-to-column connection for extendable draft platform

A mechanism to be applied to an exterior surface of a cylindrical structure for the reduction of the effect of Vortex Induced Vibration (VIV) in the cylindrical structure when immersed in flowing fluid, wherein the mechanism includes a generally cylindrical column having a central axis, an interior surface corresponding in size and shape to the exterior surface of the cylindrical structure to which the mechanism is to be applied and an outer surface defining a wall thickness. A reduced wall thickness is formed into the outer surface in a pattern to produce a discontinuity that interrupts the lengthwise coherence of vortex shedding of moving fluid from the outer surface when the cylindrical column is attached to the exterior of the cylindrical structure in the flowing fluid. The effect of VIV on the cylindrical structure is effectively reduced. The result is a submergible cylindrical assembly for positioning in a flowing body of water and having enhanced resistance to VIV.

Vortex-induced vibration reduction device for fluid immersed cylinders

An extendable draft offshore oil and gas drilling and production platform ('EDP') includes a buoyant deck having a central opening, an adjustably buoyant pontoon, and a single, adjustably buoyant column. The column is mounted upright on the pontoon, and is vertically movable through the central opening of the deck. The deck is supported on an upper end of the column above a body of water for offshore operations. The pontoon, and optionally, the column, have compartments with a buoyancy that is adjustable by pumps or sea water ballast and pressurized air. In one embodiment, the compartments can comprise a plurality of tubes. In another embodiment, a lower end of the column may comprise an open truss structure. The platform combines the advantages of a SPAR platform with those of a deep draft extendable draft platform.

Single column extendable draft offshore platform

A heave suppressed, floating offshore drilling and production platform comprises vertical columns, lateral trusses connecting adjacent columns, a deep-submerged horizontal plate supported from the bottom of the columns by vertical truss legs, and a topside deck supported by the columns. The lateral trusses connect adjacent columns near their lower end to enchance the structural intergrity of the platform. During the launch of the platform and towing in relatively shallow water, the truss legs are stowed in shafts within each column, and the plate is carried just below the lower ends of the columns. After the platform has been floated to the deep water drilling and production site, the truss legs are lowered from the column shafts to lower the plate to a deep draft for reducing the effect of wave forces and to provide heave and vertical motion resistance to the platform. Water in the column shafts is then removed for buoyantly lifting the platform so that the deck is at the desired elevation above the water surface.

Growing community of inventors

Katy, TX, United States of America

Qi Xu