drive shoe vs casing driver underreamer tabs

Eccentric Underreamer Casing Driver Style

The Holte Casing Driver (CD) was designed to be small and compact as well as hard hitting like a Down Hole Hammer (DHH). While the CD cycles fast like a DHH it is able to be designed around a much larger piston since it is above ground, in turn, deriving an extremely powerful impact for driving casing, allowing your DHH to run most efficiently since its energy is not absorbed trying to pull casing along with it.

The Holte Casing Driver is designed to be used with a DHH and underreamer, and is available in four sizes from an easily portable size for light duty rigs to a heavy duty size for the most extreme well and hole conditions.

The casing drive acts similar to a down hole hammer. When the hole is first started, the casing driver sits inactive on top of the casing and acts as a water diverter. When the underreamer advances 1” ahead of the casing the anvil closes and the driver starts operating. The more the anvil is closed, the harder the casing driver hits.  The CD turns on and off automatically and runs only when the casing lags behind the underreamer, causing the anvil to close. There is only 1 1/4” of vertical movement of the CD anvil so the casing will always remain within 3” of the bit.