IADC
|
Parameters
|
Rock formation
|
|
Wob(kn/mm)
|
Rpm(r/min)
|
|
116 117
|
0.35-0.8
|
150-80
|
Low compressive strength extremely soft formation of high drillability, such as clay, mudstone, chalk
|
126 127
|
0.35-0.9
|
150-70
|
Low compressive strength soft formation of high drillability, such as Mudstone, gypsum, salt rock, soft shale, soft limestone
|
136 137
|
0.35-1.0
|
120-50
|
Low compressive strength soft to medium soft formation of high drillability such as anhydrite, soft shale, medium soft limestone, medium soft sandstone soft formations interlayer
|
216 217
|
0.4-1.0
|
100-50
|
High compressive strength medium soft formations , such as soft shale, anhydrite, soft limestone, medium soft sandstone and has a interlayer
|
246 247
|
0.4-1.0
|
80-50
|
High compressive strength medium hard formations such as abrasive shale, limestone, sandstone, dolomite and anhydrite, marble
|
417 437 447
|
0.35-0.9
|
150-70
|
Low compressive strength and high drill ability of extremely soft stratum, such as clay, shale, gypsum and halite, soft shale, soft limestone
|