Various Cuttings Catching Methods and Results
The following methods can be used in catching cuttings as they come from the drill hole:
- Flow line sampling and sluice box.
- Cuttings scraped from screen.
- Samples collected on a board or bucket placed in front of screen
- A mechanical device taking cuttings from the flow line (3/16" screen).
The following chart outlines advantages and disadvantages of each method using the following criteria. These conclusions are based on a "Hugh bit" paper of actual cuttings size under most drilling conditions.
- Percent of actual cuttings to cavings and whippings.
- Average percentage of drilled interval collected.
- Requirement for washing and post screening.
- Normal percentage of actual cuttings retained that represent 111the 5 metre drilled interval.
- Loss of drilling mud from system.
- Dilution of mud by wash water.
- Loss of "fines" (under 40 mesh) dependent on mud viscosity, material and screen mesh, assuming some percentage of "fines" are "mud balled" and pass over screen regardless of normal mesh. High speed shakers create a minimal "fines" loss.
- Amount of water used to pre-wash samples.
|
A |
B |
C |
D |
E |
|
|
1. |
15% |
15% |
15% |
50% |
90% |
|
2. |
24%-100% |
10%-1% |
50%-10% |
100% |
100% |
|
|
NO PLUGGING |
NO PLUGGING |
|||
|
3. |
YES |
YES |
YES |
NO |
NO |
|
4. |
15%-2.5% |
1%-0.1% |
5%-1% |
50% |
90% |
|
5. |
YES |
MINIMAL |
MINIMAL |
YES |
MINIMAL |
|
6. |
NO |
NO |
NO |
YES |
NO |
|
7. |
MINIMAL |
20%-90% |
20%-90% |
MINIMAL |
20%-90% |
|
8. |
MINIMAL |
MINIMAL |
MINIMAL |
HEAVY |
MODERATE |