| 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 limstone,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 for mations 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 ang 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,mediun soft limestone,medium soft sandstone,medium formation with harder and abrasiver interbeds.etc. |
| 617 627 |
0.45~1.1 |
90~50 |
Medium hard formations with high compressive strength such as hadr shale,limestone,sandstone,dolomite,etc. |
| 637 |
0.5~1.2 |
80~40 |
Hard formations with high compressive strength, such as sandstone,limestone,dolomite,hard gypsum,marble,etc. |
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