Bit Selection
When selecting a bit there are 3 main factors that contribute to decision making
○ Rock Hardness
○ Rock Formations
○ Bit Characteristics
• Rock Hardness
Measured using MOHS hardness scale: The Mohs scale of mineral hardness is a qualitative ordinal scale that characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material.
• Rock Formations
Rock types are classified by their different chemistry and structure. Hardness in theory is relative; therefore, soft rocks can prove more difficult to drill than hard rock. Also, the same rock formations, in different locations, can drill differently.
Factors that Determine Drillability
○ Grain Size
○ Rock Hardness
○ Weathering and Fracturing
• Bit Characteristics
Matrix – Each of the matrices has a different rate of wear. The matrix chosen is ideal when there is a balance between the wear of the matrix material and the diamonds exposing ensuring a high rate of penetration and optimum bit life.
Gauge – The outer (hole) and inner (core) dimensions of the bit
Crown Height – Ranging from 4mm to 18mm in height. With higher crowns available upon request. The height of the crown is chosen based of hole depth and wear rate.
Waterways – There are multiple different waterway configurations depending on the drilling conditions
HAYDEN uses a number reference guide (Hayden 1-16), corresponding to the matrix hardness for ease of selection. (Hayden 1 being the hardest matrix and Hayden 16 being the softest.) The higher the number, the harder, finer grained, more competent and non-abrasive the rock type the bit is capable of drilling. Conversely, the lower the number selected the more broken,fractured coarser grained and abrasive a formation the bit is capable of drilling.
We manufacture slight variances of the standard matrices to fine-tune the bits performance considering the drill rig capabilities and formations being encountered.
Customization
HAYDEN is capable of designing and manufacturing bits to any customer specifications and the worlds exploration industry.