type | IADC Code | Applicable formation | Main characteristics of the bit | Recommended parameters | |
Cutting structure | Normal WOB KN/mm(bit dia.) | Rotary Speed(rpm) | |||
TH437 | 437 | Very soft with low compressive strength and high drillability,such as(clay,loose sandstone,soft mudstone,salt bed,etc) | Large dia,scoop chisel tngsten carbide compacts,high compact exposure. | 0.50-0.70 | 150-60 |
TH447 | 447 | Very soft to soft with low compressive strength such as,(clay, shale, stansstone,salt bed and soft limestone etc.) | Large dia conical and conical scoop chisel tungsten carbide compacts,high compact exposure. | 0.50-0.70 | 150-60 |
TH517 | 517 | Soft with low compresive strength and high drillability,such as mudstone,shale,salt bed,standstone and soft limestone,etc. | Large dia scoop chisel tungsten carbide compacts | 0.50-0.90 | 100-45 |
TH527 | 527 | Soft with thin &hard stringers,such as salt bed,mudstone,sandstone,soft limestone and hard shale,etc. | Conical and conical scoop chisel tungsten carbide compacts. | 0.50-0.90 | 100-45 |
TH537 | 537 | Soft to medium soft with low compressive strength,such as hard shale,mudstone,soft limestone and sandstone,etc. | The inner row compacts are scoop chisel ,and heel row are wedge compacts. | 0.60-0.90 | 80-40 |
TH547 | 547 | Soft to nedium soft with harder & abrasive stringers,such as hard shale,mudstone,soft limestone and sandstone,etc. | Conical compacts in inner row, spherical compacts in outer row,with on more row of compacts than TH537 | 0.60-0.90 | 80-40 |
TH617 | 617 | Medium hard with high compressive srength,such as limestone,dolomit,hard shale and sandstone,etc. | The inner row compacts are conical and heel are blunt wedge compacts | 0.7-1.00 | 60-45 |
TH627 | 627 | Medium hard with high compressive strength and hard streaks,such as limestone,dolomite,hard sandy formation and sandstone,etc. | Conical compacts in inner row,spherical tungsten caride compacts in heel row. | 0.8-1.00 | 55-45 |
TH637 | 637 | Medium hard with high compressive strength and abrasiveness,such as limestone,hard sandstone and chert,etc. | Conical compacts in inner row,spherical tungsten caride compacts in heel row. | 0.8-1.00 | 55-45 |
TH737 | 737 | Hard with high abrasiveness, such as hard limestone,dolomite,hard sandstone and chert,etc. | Spherical compacts in rose row and heel row,conical spherical compacts in inner row | 0.8-1.00 | 60-45 |
TH838 | 838 | Very hard with high compresive abrasiveness,such as quartzite,sandy quartzite,chert,and basalt etc. | Spherical tungsten carbide compacts in each row | 1.10-1.30 | 60-45 |
