June 22, 2022
IADC
Rock formation
WOB (KN/mm)
PRM(r/min)
417/427/437
Low compressive strength, high drill-ability and extremely soft formation, like shale, clay, sandstone, conglomerate etc
0.35~0.90
140~70
447
Low compressive strength, high drill-ability and soft formation, like shale, clay, sandstone, soft limestone, salt rock, plaster etc.
0.35~1.00
140~60
517
Low compressive strength, high drill-ability and soft formation, like shale, clay, sandstone, soft limestone, salt rock, etc
0.35~1.05
120~50
527
Soft formation with low compressive, like Low compressive strength, high drill-ability and soft formation, like shale, clay, sandstone, soft limestone, salt rock, anhydrite etc.
0.35~1.05
120~50
537/547
Low compressive strength, medium hard formation with hard abrasive interlayer, like Hard shale, anhydrite, soft limestone, sandstone, dolomite with mezzanine, etc.
0.50~1.05
110~40
617/627
High compressive strength, medium hard and thick hard interlayer, like hard shale, limestone, sandstone, dolomite, etc.
0.50~1.05
80~40
637/737
High compressive strength, medium hard and high abrasive formation, like limestone, dolomite, sandstone, chert, etc.
0.7~1.20
70~40