Tong for wellbore operations

A tong for use in wellbore operations, the tong comprising:

• a housing with a hollow interior;
• a plurality of jaw assemblies, at least one of which is movably mounted in the hollow interior of the housing for selectively engaging a portion of a tubular to be gripped and rotated by the tong, the jaw assemblies configured to resist both axial and rotational movement of the tubular upon engagement therewith;
• a gear structure on the housing for mating co-action with a tong drive apparatus;
• a gear retention member for axially retaining the gear structure;
• and
• a bearing between the gear retention member and the gear structure for facilitating movement of the gear structure with respect to the gear retention member and for dissipating axial stress when the gear structure and the gear retention member are moved axially relative to each other.

A method for rotationally connecting two threaded tubulars, wherein at least one of the tubulars is subjected to an axial force created by a fluid pressure acting over at least a portion of a cross-sectional area of the at least one tubular, comprising the steps of:

• providing a tong which is sized and configured to withstand the axial force, the tong having:
• a housing with a hollow interior;
• and
• a plurality of jaw assemblies, at least one of which is movably mounted in the hollow interior of the housing for selectively engaging a portion of the at least one tubular;
• gripping the at least one tubular with the tong;
• rotating the at least one tubular with the tong, thereby relatively manipulating the threads between the two tubulars;
• and
• dissipating axial stress through a bearing.

A system for continuously circulating fluid to and through a tubular string while an upper tubular is connected or disconnected from a top tubular of the tubular string, the system comprising:

• a tong having:
• a housing with a hollow interior;
• a gear secured to the housing, the gear having a toothed portion for mating with teeth of a drive shaft of a driving motor;
• a gear flange mounted on top of the gear so that rotation of the gear does not rotate the gear flange;
• and
• one or more bearings disposed between the gear and the gear flange;
• and
• a plurality of spaced-apart jaw assemblies within the housing's hollow interior, each jaw assembly having a jaw for selectively engaging a portion of a tubular to be gripped and rotated by the tong, wherein each jaw assembly and the one or more bearings are configured for resisting both axial and radial loading;
• an upper chamber for receiving the upper tubular of the tubular string, said upper chamber having a bottom opening and a top opening;
• a lower chamber for receiving the top tubular of the tubular string, said lower chamber having a bottom opening and a top opening, one of said upper chamber and said lower chamber sized for accommodating connection and disconnection therein of the upper tubular and the top tubular by the tong;
• an upper sealing apparatus within said upper chamber for sealingly encompassing a portion of the upper tubular within said upper chamber;
• a lower sealing apparatus within said lower chamber for sealingly encompassing a portion of the top tubular within said lower chamber;
• and
• an apparatus for isolating the upper chamber from fluid pressure loading within the lower chamber during connection or disconnection of the upper tubular and the top tubular.