Wireline Triple Tube Core Barrels
Wireline core barrels are used when coring to greater depths, mainly because they eliminate the need to couple and uncouple the rod string each time the core is retrieved. An overshot device is dropped on a cable and directly couples onto the inner tube assembly, allowing fast retrieval of the core after each core run.
The double tube wireline core barrel is converted to triple tube by incorporating a split steel tube inside the inner tube. In addition, a piston and pump-out adaptor is provided for pumping out the split steel tube when it is full of rock core. The stop ring, core lifter case and core lifter also differ from the standard double tube core barrel, being slightly smaller in diameter in order to accept and retain the slightly smaller core.
An alternative method of converting the double tube to triple tube is by incorporating a clear, semi-rigid PVC coreliner inside the inner tube instead of the split steel tube.
Available in DCDMA sizes B, N, H. and P.
Advantages:
- Faster coring at greater depths
- Good stability due to constant diameter of the drill string
- Excellent hydraulics
- Good core recovery even in highly broken formations.
Technical Data
| Specification | Core Barrel Type | |||
|---|---|---|---|---|
| B W/L3 | N W/L3 | H W/L3 | P W/L3 | |
| Hole Diameter (mm) | 59.9 | 75.7 | 96.3 | 122.8 |
| Core Diameter (mm) | 33.5 | 45.1 | 61.1 | 83.1 |
| Kerf / Crown Thickness (mm) | 13.05 | 15.1 | 17.35 | 19.45 |
| Cutting Area (cm2) | 19.6 | 29.0 | 43.5 | 64.2 |
| Hole Area (cm2) | 28.3 | 45.0 | 72.8 | 118.5 |
| Cutting Area as % of Hole Area | 69% | 64% | 60% | 54% |
| Core Area (cm2) | 8.7 | 16.0 | 29.3 | 54.3 |
| Recommended Drill Rod | BWL | NWL | HWL | PWL |
| Recommended Casing | BW | NW | HW | PW |
Key to Main Parts of W/L3 Core Barrel Assembly
Complete core barrel consists of:
1. Core Barrel Head
2. Pump-out Adaptor 3/4″ NPT
3. Piston Plug
4. O Ring
5. Core Ejection Piston
6. Split Inner Tube 1.5m or 3.0m
7. Inner Tube 1.5m or 3.0m
8. Stop Ring
9. Core Lifter
10. Core Lifter Case
11. Locking Coupling
12. Adaptor Coupling
13. Landing Ring
14. Outer Tube 1.5m or 3.0m
15. Inner Tube Stabilizer
16. Thread Protector
Core Bit and Reaming Shell are not supplied as part of the core barrel assembly, but must be chosen correctly to match the particular application and rock formation. Please refer to our Core Bits page for further details.
