12 1/4" FSG124 , 311mm Steel Tooth Bit , Sealed Roller Bearing , Tricone Roller Bit , Alloy Hard Facing on Tooth
SIZE AVAILABLE
From 5 7/8inch to 36inch
RECOMMENDED DRILLING PARAMETERS FOR APPLICATION
Types & IADC Code | 114 115 | 124 125 | 134 135 | 214 215 | 244 245 | 324 325 | |
WOB | KN/mm(Bit Dia.) | 0.3~0.75 | 0.3~0.85 | 0.3~0.95 | 0.35~0.95 | 0.35~0.95 | 0.4~1.0 |
Lb/in. (Bit Dia.) | 1712~4285 | 1715~4857 | 1715~5428 | 2000~5428 | 2000~5428 | 2285~5714 | |
Rotation Speed (Rpm) | 200~80 | 200~80 | 180~80 | 180~80 | 180~60 | 150~60 |
The above chart represents commonly available sizes and types, we do produce other sizes and types of rock bits which do not appear on this list. Please contact us for more information.
The ROP will also be affected by the rotary speed of the bit and an optimum speed must be determined. The RPM influences the ROP because the teeth must have time to penetrate and sweep the cuttings into the hole. Figure 28 shows how ROP varies with RPM for different formations. The non-linearity in hard formations is due to the time required to break down rocks of higher compressive strength. Experience plays a large part in selecting the correct rotary speed in any given situation.
The RPM applied to a bit will be a function of :
a. Type of bit
In general lower RPMs are used for insert bits than for milled tooth bits. This is to allow the inserts more time to penetrate the formation. The insert crushes a wedge of rock and then forms a crack which loosens the fragment of rock.
b. Type of formation
Harder formations are less easily penetrated and so require low RPM. A high RPM may cause damage to the bit or the drill string.