IADC | WOB | RPM | Application |
(KN/mm) | (r/min) |
437/447/435 | 0.35-0.9 | 240-70 | very soft formations with low compressive strength and high drill ability, like clay, mudstone, chalk, gypsum, salt, soft limestone |
517/527/515 | 0.35-1.0 | 220-60 | soft formations with low compressive strength and high drill ability, like mudstone, gypsum, salt, soft limestone |
537/547/535 | 0.45-1.0 | 220-50 | soft to medium formations with low compressive strength, like medium, soft shake, medium soft limestone, medium soft sandstone, medium formation with harder and abrasive interbeds |
617/615 | 0.45-1.1 | 200-50 | medium hard formation with high compressive strength, like hard shale, limestone, sandstone, dolomite |
637/635 | 0.5-1.1 | 180-40 | hard formation with high compressive strength, like limestone, sandstone, dolomite, hard gypsum, marble |
Note: Above limitts of WOB and RRPM should not be used simultaneously |