Rig for feeding conductor pipe in offshore oil and gas wells - includes rotating column tower, displaceable rotary table and separate winches, hoists and elevators

摘要

The conductor pipe for an oil or gas offshore well is brought into the ground by means of a drilling rig comprising a conventionals kidded base to which an eccentrically mounted column is attached. The column is equipped with a rigid base and a rotating column to which a crown block and winch are attached. At the top of the column there is an independently rotating load arm to which an auxiliary hoist is attached. The column also has vertical guide rails to which an elevator hoist is attached. This hoist can be brought into a position vertically above the well or into an inoperative position by a rotation of the column as can the winch and crown block. The rotary table is mounted on a side so that it can be displaced out of the operating position. The pipe clamp immediately below the rotary table is also mountedon sides. Between the rotary table and the lower pipe clamp, there is an additional pipe clamp mounted on vertical slides which enables conductor pipe or drill pipe tube moved vertically without using the column hoists. By using separate hoisting and manipulating equipment for the conductor pipe, the switch from drilling to placing of conductor pipe and vice versa can be made quickly and, by the use of lifting clamps beneath the rotary table, a lighter tower can be used capable of greater flexibility in its range of operations.