|
IADC
|
WOB(kN/mm)
|
RPM (r/min)
|
Suitable formation
|
|||
|
417
|
0.35~0.90
|
140~70
|
Very soft with low compressive strength and high drillability,such as shale,clay,sandstone and conglomerate,etc.
|
|||
|
437
|
0.35~0.95
|
140~60
|
Very soft with low compressive strength and high drillability,such as shale,clay,sandstone and conglomerate,etc.
|
|||
|
517
|
0.35~1.05
|
120~50
|
Soft with low compressive strength and high drillability,such as shale,clay,sandstone and soft limestone,etc.
|
|||
|
537
|
0.35~1.05
|
110~40
|
Medium soft with low compressive strength and harder abrasive stringers,such as hard shale,hard gypsolyte,soft limestone,sandstone
and dolomite with stringers,etc. |
|||
|
617
|
0.35~1.05
|
80~40
|
Medium hard with high compressive strength and thick&hard stringers,such as hard shale,limestone, sandstone and dolomite,etc.
|
|||
|
637
|
0.70~1.20
|
70~40
|
Medium hard with high compressive strength and high abrasiveness,such as limestone,dolomite, sandstone and chert.ect.
|
|||
|
Note:The upper limits of WOB and RPM in above table should not be used simultaneously.
|
|
|
|
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