IADC code | WOB (KN/mm) | RPM (r/min) | Applicable Formations |
437/447/435 | 0.35~0.9 | 240~70 | Very soft formations with low compressive strength and high drillability,suchas clay,mudstone,chalk,gypsum,salt,soft limestone, etc. |
517/527/515 | 0.35~1.0 | 220~60 | Soft formations with low compressive strength and high drillability,such asmudstone,gypsum,salt,soft limestone, etc. |
537/547/535 | 0.45~1.0 | 220~50 | Soft to medium formations with low compressive strength, such as medium, softshale, medium soft limestone, medium soft sandstone, medium formation withharder and abrasive interbeds, etc. |
617/615 | 0.45~1.1 | 200~50 | Medium hard formation with high compress strength, such as hard shale,limestone, sandstone, dolomite. etc |
637/635 | 0.5~1.1 | 180~40 | Hard formations with high compressive strength, such as sandstone, limestone,dolomite ,hard gypsum, marble, etc. |
Note: The upper limits of WOB and RPM in above table should not be usedsimultaneously. | |||
