Sedco, Inc.

James E Hampton

A slip assembly particularly adapted for use in conjunction with forming a supportive connection between a subsea template or related support structure and support pilings for the template. The slip assembly comprises a floating slip bowl for receiving a plurality of cylindrical slip segments which are movable radially inwardly into gripping engagement with a support column or pile member by a hydraulic cylinder actuator assembly which is connected to a cylindrical ring having a link interconnected with each of the slip segments to permit radial inward and outward movement of the segments in response to axial extension and retraction of the actuator. The slip assembly includes an upwardly facing guide funnel for guiding the pile into a central passage through the slip assembly.

Slip assembly for subsea template

Subsea drilling and foundation templates are lowered from a semi-submersible drill rig and levelled utilizing the drill string hoisting apparatus including a heave compensator suspended from the travelling block of the hoisting apparatus, a riser string suspensed from the heave compensator and connected to the template at substantially its center of gravity and further including a constant tension rotary drum air powered hoist supported on the riser string below the heave compensator and having a tension cable secured to a fixed reference point on the seabed such as one of the template supporting piles. The tension on the cable may be selectively adjusted to dampen the motion of the riser string during levelling procedure so that the position of the template with respect to its supporting piles may be referenced and the template secured to the piles when a level condition is reached.

Installation and levelling of subsea templates

A subsea template is installed by a method which includes the steps of securing the template in a position beneath the deck of a semi-submersible drilling vessel, moving the semi-submersible drilling vessel to an appropriate offshore site and subsequently lowering the template from the semi-submersible to the sea bed. In addition, at least three anchorage templates may be loaded onto one or both of the pontoons of the semi-submersible drilling vessel at its original position and are subsequently lowered from the pontoons to their respective locations on the sea bed after the semi-submersible has moved to the offshore site.

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Peterculter, United Kingdom

James E Hampton