Abstract: The present invention is a deepwater compliant platform that has enhanced dynamic characteristics by virtue of its wide stance, eliminates conventional conductor drivepipe guides and supporting framework, and reduces the net material requirements with a substantially open interior permitted in the absence of the conductor guides. This utilizes the wide body stance to accommodate a wide riser suspension corridor through the open interior thereby allowing suspended risers to be spaced apart sufficiently to avoid interference in response to normal tower motions.

Abstract: A tensioned riser deepwater platform suitable for offshore oil and gas applications is disclosed having a foundation secured to the ocean floor, a topside facility above the ocean surface, and a vertically extending tower jacket secured to the foundation and supporting the topside facility. A plurality of substantially vertically extending risers provide fluid communication between the wells and the topside facility. These risers are connected to riser supports near their upper ends and the riser supports provide the principal load transfer between the risers and the tower jacket. Thus, the conductor guides and attendant horizontal bracing of conventional deepwater design can be substantially eliminated.

Abstract: The present invention is a method for reducing the natural period of the second harmonic response in a deepwater compliant tower by decoupling the mass of the production risers from the vertically extending compliant framework.

Abstract: An improved support system is disclosed for providing flexibility to a restrained termination of a highly pressurized, highly tensioned tubular element which extends from a subsea facility to a compliant structure. The tubular element is provided with an intermediate tension relief connection which separates a running span from a backspan and operably connects the tubular element to a support structure, transfering thereto a significant portion of the tension carried by the tubular element. This connection passes angular rotation of the tubular element but resists lateral motion, in effect forming a node in the deflection of the tubular element. A backspan is thus created in the tubular element having a tension load which is reduced from that in the running span, thereby increasing the flexibility apparent at the end of the running span, while maintaining a relatively restrained termination of the tubular element at the distal end of the backspan.

Abstract: A tensioned riser deepwater platform suitable for offshore oil and gas applications is disclosed having a foundation secured to the ocean floor, a topside facility above the ocean surface, and a vertically extending tower jacket secured to the foundation and supporting the topside facility. A plurality of vertically extending risers provide fluid communication between the wells and the topside facility. These risers are connected to riser supports near their upper ends. The riser supports provide the principal load transfer between the risers and the tower jacket and the conductor guides and attendant horizontal bracing are substantially eliminated from the design.

Abstract: The apparatus of the present invention comprises a compliant structure for use in reducing bending stress at the ends of an elongated cylindrical tether which may, for example, be used to connect a floating platform supported by a body of water to the floor thereof. The apparatus comprises a plurality of tubular support members concentrically arranged about the elongated cylindrical tether at the tether's end connection. Each tubular support member is connected to each adjacent tubular support member in a manner that allows the entire assembly of tubular members to deflect in unison as the cylindrical tether deflects.

Abstract: A flexure joint is formed at the base of a buoyant tower structure by piles driven into the ocean floor. The geometric arrangement of these piles increases the buoyant tower's resistance to lateral forces at the base, while allowing rotational displacement about any horizontal axis, and also allows wells to be directed through the piles to formations located a substantial distance from the tower.

Abstract: Apparatus and method for producing hydrocarbons from a subterranean hydrocarbon-bearing formation located beneath the floor of a body of water. A platform structure is installed on the floor over the formation and well conductors are extended down the structure and penetrate into the floor of the body of water. The conductors may include an upper vertical portion, then continually curve downwardly and outwardly through the structure above the floor in a manner maintaining a relatively smooth bore throughout the entire extent of the conductors. The conductors are extended into the floor of the body of water and wells are drilled, via the conductors, down into communication with the formation. Formation fluids are then produced from the formation via the conductors.

Abstract: Apparatus and method for producing hydrocarbons from a subterranean hydrocarbon-bearing formation located beneath the floor of a body of water. A platform structure is installed on the floor over the formation and well conductors are extended down the structure and penetrate into the floor of the body of water. The conductors may include an upper vertical portion, then continually curve downwardly and outwardly through the structure above the floor in a manner maintaining a relatively smooth bore throughout the entire extent of the conductors. The conductors are extended into the floor of the body of water and wells are drilled, via the conductors, down into communication with the formation. Formation fluids are then produced from the formation via the conductors.This is a Reissue of a Patent which was the subject of a Reexamination Certificate No. B1 Re. 28,860, dated Sept. 3, 1985, Request Nos. 90/000,412, June 27, 1983 and 90/000,607, Aug. 13, 1984.