| IADC | WOB(kn/mm) | RRM(r/min) | Applicable Formations |
| 116 117 | 0.35~0.8 | 150~80 | Very soft formations with low compressive strength and high
drillability. such as clay, mudstone, chalk, etc. |
| 126 127 | 0.35~0.9 | 150~70 | Soft formations with low compressive strength and high
drillability, such as mudstone, gypsum, salt, salt, soft shale,
soft limestone, etc. |
| 136 137 | 0.35~1.0 | 120~60 | Soft to medium 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
interbeds, etc. |
| 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 formations with harder interbeds, etc. |
| 246 247 | 0.4~1.0 | 80~50 | Medium-hard formations with high compressive strength,such as
abrasive shale,limestone,sandstone,dolomite,hadr gypsum,marble,etc. |
| 417 437 447 | 0.35~0.9 | 150~70 | Very soft formations with low compressive strength and high
drillability, such as clay, gypsum, salt, soft shale, soft
limestone, etc. |
| 517 527 | 0.5~1.0 | 140~60 | Soft formations with low compressive strength and high drillability
such as mudstone, gypsum, salt, soft shale, soft limestone, etc. |
| 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 limestone,
medium soft sandstone, medium formation with harder and abrasives
interbeds. etc. |
| 617 627 | 0.45~1.1 | 190~50 | Medium-hard formations with high compressive strength such as hard
shale, limestone, sandstone, dolomite, etc. |
| 637 | 0.5~1.2 | 180~40 | Hard formations with high compressive strength, such as sandstone,
limestone, dolomite, hard gypsum, marble, etc. |
