The surface-set diamond core bits are set with a singular layer of natural or synthetic diamond utilizing a hard matrix compound on the face of the bit. The diamond set design ensures sufficient overlap to prevent premature wear of the matrix.

Surface-set diamond core bits are primarily recommended for use in drilling relatively soft, abrasive, unconsolidated formations that are not effectively drilled by impregnated diamond bits. They are also recommended for use in drilling harder formations where the available rotational speeds and bit loads are insufficient to use impregnated diamond bits due to drilling equipment limitations.

Bit Crown Profiles for Diamond Core Bits:

To suit various drilling conditions encountered and meet worldwide customer's requirements, our engineers produces core bits in corresponding crown profiles.

The basic profiles are below. Some special profiles may not be available in certain bit sizes due to the improper kerf width or matrix hardness of the bit.

W Profile - Standard profile for most impregnated diamond drill bits, usually produced in a matrix height over 6mm. It provides good drilling stability and is suitable for various formations.

Flat Profile - It's suitable for various rocks, often used in impregnated casing bits & casing shoe bits as well as the bits with very hard matrices F1/ F2 series.

Cross Profile - It's especially designed for ultra-hard formations, such as granite (hardness 8-9), ganister, quartzite, siliceous limestone, chert, etc.

Semi-Round Profile - Impregnated diamond bits with this profile are recommended for use in highly fractured formations with good drilling stability. Surface set diamond bits of this style have a long drill life and the matrix is not easy to be damaged.

Multi-Step Profile - Multi-step type impregnated diamond bits are suitable for soft to medium hard formations and alternating hard- soft formations. With very good drilling stability, it makes the borehole not liable to deflection and the penetration fast. This profile is also often adopted in thick-kerf surface set diamond core bits, with good drilling stability and fast penetration.

Waterway Configurations:

1. Standard Type (no discharge hole) - Waterway without discharge hole is the standard type, applied in many normal formations.

2. Wide Type - This waterway is wider than the standard type, applied in formations in which there is much rock debris, eg. clay, shale, coal gangue, etc.

3. Turbo Type - It's suitable for relatively hard fractured formations or hard competent formations.

4. Wide Turbo Type - Suitable for medium hard fractured formations where there is much slurry and rock debris.

5. Round Face Discharge Hole Type - It's suitable for triple core barrels, to improve recovery rate. It reduces the flushing fluid's erosion against the core during drilling.

6. Slot Face Discharge Hole Type - It's often adopted in PDC bits, TSP bits, and has bigger flow capacity, which minimizes the occurrence of discharge hole blockage. It's suitable for drilling in fractured formations where there is much flushing fluid and rock debris.

Notes:

WLA - AQ

WLB - BQ

WLN - NQ

WLH - HQ

WLP - PQ

Imp. - Impregnated Diamond Type

S.S. - Surface set Diamond Type

T.C. - Tungsten Carbide Type

PDC - Polycrystalline Diamond Compact Type

TSP - Thermally Stable Diamond Polycrystalline Type

E.P. - Electroplated Diamond Type