Improvements In Or Relating To Well Abandonment and Slot Recovery

A method of cutting and pulling casing, the method comprising the steps:

• (a) providing a casing cutting and pulling assembly on a drill string, said casing cutting and pulling assembly comprising, in order, from surface:
• a casing spear to anchor to casing in a well bore;
• a mud motor operated by fluid flow through the drill string so as to rotate the drill string and all tools mounted thereon below the mud motor;
• a casing cutter configured to cut the casing, the casing cutter including a plurality of blades which move from a retracted position to an extended position on fluid pressure in the drill string;
• characterised in that:
• the casing spear is operated by fluid pressure in the drill string;
• a valve is mounted in the drill string between the casing spear and the casing cutter, the valve limiting fluid pressure through the drill string to the casing cutter until the casing spear is anchored to the casing;
• (b) running the drill string through a wellhead location into a wellbore comprising casing;
• (c) locating the casing spear and casing cutter below the wellhead at a position at which the casing is to be cut;
• (d) increasing fluid pressure through the drill string to a first pressure to anchor the casing spear to the casing;
• (e) further increasing fluid pressure through the drill string to a pre-determined pressure level, greater than the first pressure, to operate the valve;
• (f) using fluid pressure below the valve to extend the blades of the casing cutter and cutting the casing by rotation via the mud motor;
• (g) reducing the fluid pressure so as to retract the blades of the casing cutter;
• (h) pulling the drill string so as to recover a cut section of the casing.