8 1/2 inch PDC bit
Bit diameter | 8 1/2" |
Body Type | Steel |
Number of Blades | 6",5 blades;8 1/2",6 blades |
Thread Connection | 4 1/2 API REG PIN |
Primary Cutters and Secondary Cutters Number | 16mm*24pcs;13mm*40pcs |
Gauge Cutters Number | 13mm*32pcs |
Gauge Protection Cutters Number | 13mm*28pcs |
Back Reaming Cutters Number | --- |
Gauge Protection Materials | Tungsten Carbide,PDC cutter |
Gauge Protection Type | Normal |
Length of Gauge Protection | --- |
Number of Nozzle | 8 1/2" - 6 pcs;6" - 5pcs |
Total Flow Area(TFA) | --- |
Junk Slot Area | --- |
Production Standard | API Spec 7-1 |
Polycrystalline diamond compact (PDC) bits deliver premium performance and durability for a wide range of standard drilling applications. These matrix- and steel-bodied bits incorporate the latest cutter technology, computational fluid dynamics (CFD), enhanced hydraulics, and various structure geometries to maximize ROP.
**Matrix-body bit
Matrix-body PDC bits are commonly preferred over steel-body bits for environments in which body erosion is likely to cause a bit to fail. For diamond-impregnated bits, only matrix-body construction can be used.
** Steel-body bits
The strength and ductility of steel give steel-bit bodies high resistance to impact loading. Steel bodies are considerably stronger than matrix bodies.A beneficial feature of steel bits is that they can easily be rebuilt a number of times because worn or damaged cutters can be replaced rather easily. This is a particular advantage for operators in low-cost drilling environments.
Rock hardness and bit selection | |||||
Cone bit IADC code | PDC | Formation | Rock Types | Compressive strength (Mpa) | ROP(m/h) |
111/124 | M/S112~M/S223 | Very soft: low viscosity, low compressive strength. |
clay siltsone sandstone |
<25 | >20 |
116/137 | M/S222~M/S323 | Soft: the formation is soft with low compressive strength and good drillability. |
Clay rocks lignite sandstone |
25~50 | 10~20 |
417/527 | M/S323~M/S433 | Medium soft: weak to medium, low compressive strength. |
Clay rocks sandstone siltstone anhydrite limestone |
50~75 | 5~15 |
517/537 | M322~M443 | Medium to hard formation with high compressive strength and poor abrasion resistance. |
mudstone Sandy limestone shale |
75~100 | 2~6 |
537/617 | M422~M444 | Medium hardness: hard, dense formation with high compressive strength and moderate wear. |
The marble granite Hard shale anhydrite sandstone dolomite schist |
100~200 | 1.5~3 |