Diverless subsea template levelling system and method

Abstract

A diverless system for levelling a template adjacent the floor of a body of water comprising a plurality of fluid-pressure activated gripping assemblies pivotally coupled to the template and receiving the supporting piles therein, with portions of the piles extending above the template; and a jacking assembly capable of being lowered down each of the piles, releasably connected to the template adjacent the associated gripping assembly and raising or lowering the template in the area each of each pile to level the template. The jacking assembly comprises an outer housing, and a double acting hydraulic piston slidably received in the housing, with a pile gripping assembly being coupled to the piston. The gripping assembly in the jacking assembly and those in the template are each formed from a plurality of ring segments that are serrated on the inside and have tapered ribs on the outside, these segments being received in a bowl having corresponding tapered ribs. The segments are spring biased upwardly and inwardly into the pile gripping position and released downwardly and outwardly by hydraulically actuated pistons. Without diver intervention, fluid under pressure is delivered to the gripping assemblies coupled to the template. The method of installing the template comprises landing the template on the floor of the body of water, passing a set of casing piles through passageways in the template and implanting the casing piles in the floor of the body of water with portions of the piles extending above the template, levelling the template, and rigidly connecting the levelled template to the piles. The step of levelling the template includes actuating the gripping assemblies coupled to the template. This step is preceded by the step of remotely delivering fluid under pressure from a fluid reservoir at the surface of the sea to each gripping assembly without underwater manual, i.e., diver, intervention.