US Patent 10458196 Downhole casing pulling tool

A method and apparatus for cutting and pulling a casing string from a well. A downhole casing pulling tool includes a tubular housing having a bore therethrough, a packer assembly configured to isolate an annulus between a casing and the tool, a slip assembly configured to engage the casing, and a piston assembly disposed in the bore of the tubular housing. The piston assembly is configured to operate an actuator, wherein the actuator is configured to operate at least one of the packer assembly and the slip assembly and modify a fluid pressure in the bore of the tubular housing.