A new high-pressure coiled-tubing (CT) drilling system has been developed with support from the DOE that drills 2 to 3 times faster than conventional CT motors. Downhole motors have been developed that utilize diamond thrust bearings, titanium flexshafts, high-pressure rotor/stator sections and other advanced features that allow these motors to operate at high pressures. Laboratory tests have been conducted using the high-pressure system to cut 1 to 2 inch deep helical slots in wellbore walls to remove formation damage (patent pending) and to drill cement out of drillpipe at rates up to 1,400 ft/hr compared to 60 ft/hr for conventional motors. This jet-drilling system can also be used to remove barite scale from tubing, to clean slotted liners, to ream holes at high rates, and to under-ream when drilling with casing. The high-pressure system will be field tested and commercialized during the next phase of this DOE project.

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