Spiral drill collar

The Spiral Drill Collar is made from AISI 4145H modified alloy steel, and completely meets the requirement of API Spec 7-1 and SY/T5144 Standard. It is a kind of drill collar which adds three dextrogyrate spiral groove on the outer circle of ordinary drill collar when processing, and the purpose is to reduce the area of contact and friction with the well wall, which can effectively prevent the pressure sticking. The single weight of the spiral drill collar is round about 4% lighter than the ordinary drill collar with the same specification, and the shape and thread of the both ends are the same with the drill collar.

OD		Depth of cut(mm)	±25.4 Pitch(mm)	Depth of cut (mm)
mm	in	Depth of cut(mm)	±25.4 Pitch(mm)	Depth of cut (mm)
98.4	3 7/8	4.0±0.79	914
101.6~111.1	4~4 3/8	4.8±0.79	914
114.3~130.2	4 1/2~5 1/8	5.6±0.79	965
133.4~146.1	5 1/4~5 3/4	6.4±0.79	1067
149.2~161.9	5 7/8~6 3/8	7.1±1.59	1067
165.1~177.8	6 1/2~7	7.9±1.59	1168
181.0~200.0	7 1/8~7 7/8	8.7±1.59	1626	5.6±0.79
203.2~225.4	8~8 7/8	9.5±1.59	1727	6.4±0.79
228.6~250.8	9~9 7/8	10.3±2.37	1829	7.1±1.59
254.0~276.2	10~10 7/8	11.1±2.37	1930	7.9±1.59
279.4	11	11.9±2.37	2037	8.7±1.59