Apparatus and methods for drilling with casing

A method of drilling with casing, comprising:

• running a string of casing into a wellbore, the string having a drilling member at a lower end to form a borehole as the string is run;
• and
• utilizing an energy transfer assembly operatively connected to the casing, the energy transfer assembly adding energy to upwardly traveling fluid in an annulus defined between the casing and the wellbore.

A removable energy transfer assembly for use in a tubular string run-in to a wellbore comprising:

• motor portion and a pump portion, the motor portion in fluid communication with fluid in the tubular and the pump portion in fluid communication with fluid in an annulus;
• at least one latch assembly temporarily holding the assembly in a first position in an interior of the tubing, the latch assembly being selectively disengageable;
• an isolating member axially movable in the tubular to seal the tubular as the energy transfer assembly is removed.

A method of reducing equivalent circulation density (ECD) in a wellbore while lowering casing in the wellbore, comprising:

• running the string of casing into the wellbore, the string including an energy transfer portion operatively connected thereto;
• transferring energy with the energy transfer portion from fluid pumped down the string to fluid circulating upwards in an annulus.

A method for placing a casing string in a wellbore comprising:

• lowering the casing string into the wellbore;
• and
• pumping fluid into an area within a wall of the casing string, the fluid circulating through an energy transfer assembly and to an area outside the wall, thereby adding energy to the fluid outside the wall.

An energy transfer assembly for use while drilling with casing, comprising:

• a restriction in an interior of the casing, the restriction constructed and arranged to create a back pressure of fluid in an area adjacent the restriction;
• at least one fluid path between the interior of the casing and an annulus therearound;
• whereby at least a portion of fluid traveling in a first direction in the interior of the casing is directed into the annulus via the at least one fluid path.

A casing string for lowering into a wellbore comprising:

• a tubular wellbore string with an interior and an exterior;
• an energy transfer assembly operatively connected to the tubular string for transferring energy between the interior and the exterior;
• the energy transfer assembly in communication with a power source.