Abstract: A concentric casing jack is disclosed having a casing supporter and actuator that uses hydraulic fluid to vertically raise and lower an inner concentric string of casing in a well. This casing jack is connected to a string of casing and can operate down-hole tools attached to the lower end of the casing by actuating the casing. The casing jack is supported at the surface by the wellhead and can be incorporated into a series of drilling spools and blowout preventer valves that are commonly utilized during drilling operations. The casing jack consists of a housing and a hollow piston whose internal diameter is similar in size to the concentric casing. The similar sizing allows drill bits and bottom hole assemblies to pass through the hollow center of the casing jack and the attached string of casing. The piston is equipped with external seals to hold hydraulic pressure between the hollow piston and the body of the jack.

Abstract: A concentric casing jack is disclosed having a casing supporter and actuator that uses hydraulic fluid to vertically raise and lower an inner concentric string of casing in a well. This casing jack is connected to a string of casing and can operate down-hole tools attached to the lower end of the casing by actuating the casing. The casing jack is supported at the surface by the wellhead and can be incorporated into a series of drilling spools and blowout preventer valves that are commonly utilized during drilling operations. The casing jack consists of a housing and a hollow piston whose internal diameter is similar in size to the concentric casing. The similar sizing allows drill bits and bottom hole assemblies to pass through the hollow center of the casing jack and the attached string of casing. The piston is equipped with external seals to hold hydraulic pressure between the hollow piston and the body of the jack.