The purpose of this paper is to present the relevant factors surrounding the use of turbo drills for straight-hole applications. The presentation begins with the developmental background and mechanics of the turbine as well as the necessary conditions under which it must operate. Subsequently, the hydraulic considerations, diamond bit selection and standard operating procedures are examined. Finally, the procedures are examined. Finally, the economics of the turbine decision is reviewed.


The oil industry has been ever searching for a less expensive and more effective method of reaching the drilling target. One approach has been to design and test a variety of down-hole motors. These motors have included mud-driven turbines, positive displacement mud motors and electrically powered motors. Of these, the most powered motors. Of these, the most attractive have been the turbines and the positive displacement motors. Since the mud is already being used to remove the cuttings, its presence makes it a likely candidate for providing power to a drilling motor.

Turbines are not new as far as their application to drilling is concerned. The possibility of using a turbine as a down-hole motor to power the bit was first recognized in 1873 when C.G. Cross was issued a U.S. patent. Conventional rotary drilling was later patented in 1884, but further patented in 1884, but further development of the turbine in the Western world was sporadic. Various turbo drill designs were tested but the main failing of American designs was the excessive bearing failure brought about mainly by the action of abrasive drilling fluids. The Russians surmounted this problem in the 1950's by developing rubber compound thrust bearings which could tolerate the abrasiveness.

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