Abstract A traveling support frame is mounted for up and down travel by two parallel guide columns secured at their lower ends to a base frame. A portion of the traveling frame projects laterally of the drive columns and supports two drive motors, two reducing gearing assemblies, a collector gearing assembly and drive head means. The traveling frame and equipment carried thereby are moved up and down by triangularly arranged thrust ram means, each comprising a downwardly opening, upwardly projecting, piston chamber having a lower mounting portion originally secured to the traveling frame and a downwardly directed piston having a lower mounting portion secured to the base frame. The drive head includes a breakout wrench having a plurality of laterally swinging wrench jaws moved in and out by linear fluid motors. The wrench jaws have radially inwardly directed wrench portions which are like spanner wrenches. The free end of each wrench jaw makes abutting contact with a shank portion of the adjacent wrench jaw, so that in use the wrench jaws brace each other and form a compression ring surrounding the engaged drill pipe. The drill head includes a tool joint component which is movable axially a limited amount relative to the traveling cross frame. A connector rod connects this tool joint component to the piston of a linear fluid motor supported axially above the drill head. Fluid is introduced into the motor below the piston for the purpose of counterbalancing the weight of the drill head and any drill pipe connected thereto. A holding wrench is located below the turning wrench. It comprises a plurality of wrench jaws pivotally mounted for lateral swinging movement, a surrounding control ring, and individual links interconnected between each wrench jaw and the control ring. The control ring is rotated by linear fluid motors. Rotation in one direction causes the links to move the wrench jaws radially inwardly into a position of engagement with holding wrench receiving portions on drill pipe, and movement in the opposite direction causes the links to move the wrench jaws radially outwardly in space relationship from the drill pipe.
A method of loosening a threaded connection between first and second drill pipe sections, the first of which is thread connected to a threaded tool joint component carried by a rotatable drive head which during drilling is both rotated and moved axially, and the second of which is thread connected to the first section, said method comprising: substantially counterbalancing the combined weights of the drive head tool joint component and the first drill stem section connected thereto by use of a fluid motor interconnected between a frame and said drive head tool joint component; gripping the second drill pipe section and restraining it against both rotation and axial movement; coupling the first drill pipe section to the drive head at a location on said first drill pipe section which is axially inwardly on the first drill pipe section from the tool joint between it and the drive head tool joint component; rotating said drive head and the first drill pipe section coupled thereto in a thread loosening direction until the tool joint between the two sections loosens; and using said fluid motor for moving the drive head tool joint component and the first drill pipe section axially relative to the drive head proper an amount sufficient for accommodating thread travel at the loosened tool joint.
Claim 2
Independent Claim
215 words
A method of loosening a threaded connection between first and second drill pipe sections, the first of which is thread connected to a threaded tool joint component carried by a rotatable drive head which during drilling is both rotated and moved axially, and the second of which is thread connected to the first section, said method comprising: substantially counterbalancing the combined weights of the drive head tool joint component and the first drill stem section connected thereto by use of a fluid motor interconnected between a frame and said drive head tool joint component; gripping the second drill pipe section and restraining it against both rotation and axial movement; coupling the first drill pipe section to the drive head at a location on said first drill pipe section which is axially inwardly on the first drill pipe section from the tool joint between it and the drive head tool joint component; rotating said drive head and the first drill pipe section coupled thereto in a thread loosening direction until the tool joint between the two sections loosens; and using said fluid motor for moving the drive head tool joint component and the first drill pipe section axially relative to the drive head proper an amount sufficient for accommodating thread travel at the loosened tool joint.