Spiral drill collars

 

Spiral grooves of Drill Collar can reduce the surface contacting area between well and drill collar, and effectively lower the possibility of differential pressure block or sticking, let mud circulate freely around the drill collar to equalize pressure.

 

Based on API Spec.7 and SY/T5144, the spiral drill collars are made of 4145H modified chromium–molybdenum alloy steel. All threads are phosphated, copperized or cold rolled. All threads machined with CNC Lathes –Double –shoulderd, including some special threads. The maximum outer diameter of drill collars can be to 14 inch.