APPARATUS AND DEVICES FOR THE PRODUCTION OF NATURAL GAS AND CRUDE OIL, NAMELY, MECHANIZED DRILLING AND PRODUCTION RIGS, PRODUCTION CASINGS AND PRODUCTION TREES; POWER-OPERATED MACHINE AND MACHINE TOOL PARTS FOR EARTH DRILLING AND DEEP DRILLING, NAMELY, DRILL BITS, DRILLS, UNDERREAMERS, DEFLECTORS, DOWNHOLE ROTARY DRILLING MOTORS, PACKERS, ARTICULATED DRILL STINGS, NON-MAGNETIC DRILL COLLARS AND PARTS THEREFOR, DOWNHOLE TURBINES AND ELECTRICAL GENERATORS FOR USE IN DIRECTIONAL DRILLING