Rotation speed frequency range between 200 and 450 min-1 is of particular interest when drilling oil and gas wells with PDC bits. In such cases screw down-hole motors are widely applied, but they have functional disadvantage dealing with orbital trajectory of the motor. And such a trajectory results in crossover vibrations of down-hole motor and drilling bit. Vibrations, at the same time, reduce lifetime of the down-hole motor and affect economical aspects of the drilling. That is why it is important to develop the new down-hole motor working without any vibrations of the rotor.
The analysis of academic and technical papers showed absence of the simple and effective solution to rotor and down-hole motor vibrations. For that reason it is viable to expand the research scope and study other down-hole motors designs. Current study based on the concept that every screw surface might be replaced with the set of flat and cylindrical surfaces. Experimental studies confirmed that new hydraulic machines with the unique functions might be developed based on this concept. Screw surfaces were excluded from the design and flat and cylindrical surfaces were used instead.
Study results might be applied for the purpose of deviated and horizontal oil and gas wells drilling. Using simpler and more technological geometrical shape allows some parts of the hydraulic machine to be made of hard and ultra-hard materials, which brings new opportunities for practical application of such hydraulic machines when drilling wells at huge pressure differences.
References
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