| IADC | WOB | RPM | Applicable Formations |
| (KN/MM) | (r/min) |
| (Bit Dia) |
| 116 117 | 0.35~0.8 | 150~80 | Very soft formations with low compressive strength and high drillability,such as clay,mudston,chalk etc. |
| 126 127 | 0.35~0.9 | 150~70 | Soft formations with low compressive strength and high drillability,such as mudstore,gypsum,salt,softshale.soft limestone,ect. |
| 136 137 | 0.35~1.0 | 120~60 | Soft to mesium soft formations with low compressive strength and high drillability.such as medium soft shale,hard gypsum,medium soft limestone.medium soft sandstone soft formation with harder nterbeds,ect. |
| 216 217 | 0.4~1.0 | 100~60 | Medium hard formations with high compressive strength,such as medium soft shale,hard gypsum,medium soft limestone,medium soft sandstone,soft formation with harder interbeds ect. |
| 246 247 | 0.4~1.0 | 80~50 | Medium hard formations with high compressive strength,such as abrasive shale.limestone,sandstone,dolomite,hard gypsum,marble,ect. |
| 417 437 | 0.35~0.9 | 150~70 | Very soft formations with low compressive strength and high drillability,such as clay,mudston,chalk,gypsum,salt,soft shale,soft limestone,etc. |
| 447 |
| 517 527 | 0.35~1.0 | 140~60 | Soft formations with low compressive strength and high drillability,such as mudstore,gypsum,salt,soft shale.soft limestone,ect. |
| 537 547 | 0.45~1.0 | 120~50 | Soft to medium formations with low compressive strength,such as medium soft shale,medium soft limestone,medium soft sandstone,medium formation with harder and abrasiver interbeds,ect. |
| 617 627 | 0.45~1.1 | 90~50 | Medium hard formations with high compressive strength,such as hard shale,limestone,sandstone,dolomite,ect. |
| 637 | 0.5~1.2 | 80~40 | Hard formations with high compressive strength,such as sandstone,limestone,dolomite,hard gypsum,marble,ect. |
