Page 39 - Diamond Products Catalog

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Gauge Loss ID
Cause: (A) Overfeeding (B) Broken formations (C) Drilling over lost core (D) Insufficient drilling fluid
Solution: (A) Reduce penetration rate (B) Cement or change to a lower series bit (C) Check core barrel/core lifter/core lifter case (D) Check inner tube length adjustment; check pump and rod string for leaks – increase pump output
Gauge Loss Outer Diameter
Cause: (A) Lack of circulation (B) Bit being reamed down under-size hole (C) Vibration
Solution: (A) Increase coolant flow rate (B) Check reamer shell gauge and replace if under-sized (C) Alter RPM
Excessive Diamond Exposure
Matrix abrades away before diamonds have worn sufficiently, resulting in high diamond exposure and low bit life.
Cause: Caused by overfeeding/over drilling
Solution: Increase RPM, change to a lower series bit, or reduce bit weight
Face Glazed (Diamond Polished and Metal Bound)
Bit does not feel sharp; diamonds flush w matrix; no significant “comet tails” behind each diamond.
Sand blast face or use other recommended methods to re-expose diamond. If the face glazes repeatedly, change to a higher bit.
Cracked Waterways (Diamonds Polished)
Cause: (A) Excessive bit load; dropped rods; free fall of (wireline) inner tube in dry hole; (B) bit crushed by rod holder, foot clamp or pipe wrench; (C) Pushed down an undersized hole (i.e., reaming shell worn out).
Solution: Review proper operating procedures.
Burnt
Cause: (A) Lack of fluid. (B) Too high of weight on bit being used
Solution: Check pump and rod string for leaks, check inner tube adjustment, maintain coolant flow rates