Slot recovery method

A method of slot recovery to remove multiple casings cemented in a well comprising the steps of:

• a) running an internal cutter down a production casing to laterally cut through a preselected number of existing casings in a casing string at multiple predetermined depths, wherein the internal cutter is capable of cutting through casings of different diameters;
• b) drilling around the outermost casing of a first number of casings of the preselected casings in the casing string with a hollow drill bit which is attached to a core over casing, the hollow drill bit drilling through the casing cement around the outermost casing of the first number of casings down to a first predetermined depth of the multiple predetermined depths;
• c) attaching a removal tool to the first number of casings and removing the first number of casings from the first predetermined depth to the surface;
• and
• d) repeating steps b) and c) using appropriately sized hollow drill bits and core over casings to drill around the outermost casing of the next number of casings of the preselected number of casings to a next predetermined depth of the multiple predetermined depths to continue to remove existing casings until all preselected existing casings are removed from the multiple predetermined depths.