DRILLING WITH CASING: PROSPECTS AND LIMITATIONS

Drilling with Casing is a new technology used for simultaneously drilling and casing a well where the casing is used to transmit mechanical and hydraulic energy to the bit, instead of using a conventional drill string.

The fundamental value of Drilling with Casing lies in improving drilling efficiency by eliminating flat spots in the drilling curve. It will eliminate the use of drill pipe, significantly reduce tripping times and reduce time lost due to unscheduled events such as reaming, fishing and taking kicks while tripping.

This technology utilizes a top drive to rotate the casing and uses a combination of traditional components such as standard oil field casing, bits, mud motors, MWD/LWD tools, as well as some newly developed components that allow drilling of most hole sizes from any drilling unit, with the ability to recover the drilling assembly using wireline.

This paper will describe the physical components and operational aspects of the drilling with casing system and its prospects and limitations over conventional drilling system. The anticipated results of drilling with casing are discussed and specific conclusions include in 20 30% reduction in the time required to drill wells from spud to rig release and up to 30% savings in well cost with improved reservoir productivity.