Downhole induction heating tool for enhanced oil recovery

A downhole induction heating tool for use in a well extending downward from the surface to one or more production intervals to heat well casing and thereby lower the viscosity of recovered fluid for enhanced recovery, said tool comprising:

• a magnetically permeable core;
• a conductive wire coil wound around the core;
• and
• one or more structural members extending longitudinally and internally through the core and forming a skeleton for providing reinforcement in axial compression and tension.

A downhole induction heating tool for use in a well extending downward from the surface to one or more production intervals to heat well casing and thereby lower the viscosity of recovered fluid, said tool comprising:

• a plurality of longitudinally aligned core-coil assemblies, each including a magnetically permeable core and a conductive wire coil associated therewith;
• an outer tubular housing jacketing each of the core-coil assemblies, the housing being formed of non-magnetic and electrically insulating material;
• and
• a skeleton of structural members within the housing and extending longitudinally and internally through the core-coil assemblies for providing reinforcement in axial compression and tension.

A method for heating casing in a wellborn extending downward from the surface to one or more production intervals to enhance recovery of fluids, comprising:

• providing a tool including a magnetically permeable core, a conductive wire coil wound around the core, and an outer tubular housing formed from an non-magnetic and electrically insulating material jacketing the core and the coil;
• positioning the tool in the wellbore along a production interval of a subterranean reservoir;
• and
• supplying electrical power to the coil to electro-magnetically heat the casing.