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[On the Job Tips]
There are some tricks-of-the-trade you will never know… until someone shares it with you. Fern the Driller is eager to share his experience with you.
Matrix Wear Profile Analysis
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1.
New impregnated bit
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2.
Ideal Wear : Even wear, complete up to the carbide with the diamonds evenly worn. |
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3.
Consumed bit : impregnated bit consumed perfectly and out of the hole |
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4.
Diamond overly exposed : the matrix wears too fast before the diamonds have worn out. The diamonds pop out prematurely thus reducing the life of the bit.
Caused by :
- Drilling pressure too high for the speed of rotation.
- The water flow is too low.
- The use of high series bit (too soft a matrix).
Solution :
- Increase the water flow.
- Change the bit for a lower series (harder matrix).
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5.
Core bit polished or glazed : The bit does not cut, the diamonds are polished.
Caused by :
- The drilling pressure is too low for the speed of rotation.
- The water flow is too high.
- Using a low series bit for the ground (too hard a matrix).
Solution :
- Sharpen the bit.
- Reduce the rotation speed and increase drilling pressure.
- Reduce water flow.
- Select a bit from a higher series (softer matrix).
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6.
Burnt core bit : Bit is completely melted and destroyed.
Caused by :
- Ran out of water.
- The operator forgot to open the water valve.
Solution :
- Increase water flow.
- Increase water flow.
- Check if the pump is working well.
- Check the rods for leaks in the joints.
- Confirm whether the inner tube is too long and adjust, if necessary.
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7.
Cracks in the water ways : Cracks on the sides of the water ways.
Caused by :
- Too much weight on the bit.
- Too much weight on the bit.
- Dropped the rods.
- The inner tube was dropped in a dry hole.
- The bit was crushed by the foot clamp or rod holder.
Solution :
- Take some weight off the bit (hold-back)
- If it is a “dry-hole”, send the tube back with the wireline.
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8.
Loss of inside diameter : Wear of inside diameter and inside ringing
Caused by :
- Drilling pressure too high.
- Very broken ground.
- Core left in the hole.
- Water flow too low.
- Matrix too soft.
Solution :
- Increase rotation speed
- Reduce drilling pressure
- Change for a lower series core bit (harder matrix)
- Increase water flow.
- Check the length of inner tube.
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9.
Loss of outside diameter : Wear of outside diameter and outside ringing
Caused by :
- Vibration.
- Rotation speed too high.
- Water flow too low.
- Cave in, the hole was reamed.
Solution :
- Increase water flow.
- Reduce rotation speed.
- Check the diameter of reaming shell.
- Add drilling fluids (to reduce vibration).
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10.
Inside wear pattern : Outside to inside wear of bit
Caused by :
- Drilling pressure too high for the rotation speed.
- Core left in the hole had to be drilled.
- Very broken ground.
Solution :
- Decrease drilling pressure
- Increase rotation speed.
- Check the core barrel.
- Add drilling fluids (fractured ground).
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11.
Outside wear pattern : Wear of the bit towards outer diameter
Caused by :
- Water flow too low
- Loss of water by the rods
- Hole “reamed”.
Solution :
- Increase the water flow.
- Check for leaks.
- Check the diameter of sell.
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