DRAW HEAD WITH MUDDING MECHANISM Russian patent published in 1997 - IPC

FIELD: oil and gas production. SUBSTANCE: invention relates to opening productive beds of oil and gas wells when coring and simultaneously mudding productive bed. Draw head with mudding device contains: casing; rolling cutters mounted on knuckles of drilling bit legs by means of bearings; and washing channels, one of them being equipped with hydraulic-gun head. Orifice of the latter is directed at angle 90 deg. with regard to draw head axis toward well wall at the point where draw head forms borehole with diameter equal to nominal diameter of draw head which is 190.5 mm. EFFECT: improved structure. 2 cl, 2 dwg