Torque is the amount of rotational energy imparted on a tubular connection when two joints are screwed together. The recommended torque for any particular tubular is based on the connection type and the grade of steel.
Choosing the Casing
Prior to drilling a well the maximum loads the casing will experience are calculated. The design engineer then researches various casing manufacturers for the appropriate size, grade of steel and connection type that best meets the established load requirements.
Charts and Tables
Manufacturer's charts and tables can be consulted to determine the recommended make-up torque for a particular casing or connection type. If the casing/connection is under-torqued there is the possibility of the connection leaking which could lead to casing failure. Failure also can occur if the connection is over-torqued during make-up.
Casing performance properties are readily available online from manufacturers such as U.S. Steel and TenarisHydril or from a manufacturer's representative. The manufacturer can be determined by the company's stencil on every joint.
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