The HWDP's uses AISI ***5H alloy structural steel, the technique of production
exactly carries on the SY/T********7 standard, HWDP is one kind
of medium weight and the drill pipe
similar drilling tool, its wall thickness is thicker
than the drill pipe, is thinner than the drill collar, on its
thick wall body connected
special and lengthen drilling joint. Generally adds between the
drill pipe and the
drill collar, prevents to drilling string's sudden change, reduces drill pipe's weariness; Uses in the directional well, might in compare
the low torque in the situation to sneak in high speed, reduces drilling string 's attrition and the
breakage. Because its rigidity are less than the drill collar,
less contact area with
wall of a well , is also not easy to form differential pressure
sticking.
