Downhole · PCP
TEC Cable
Tubing encapsulated cable: an insulated conductor sealed inside a small metal tube, run on the outside of the tubing from the wellhead down to the gauge at the pump.
What it does
Carries power and signal for the downhole gauge. The metal tube is the pressure barrier that protects the conductor from well fluids.
Basics
| Tube | 1/4 in, wall 0.028 or 0.035 in |
| Tube material | 316L or Alloy 825 |
| Conductor | #16 or #18 AWG stranded, FEP insulated |
| Versions | 11 mm round PP encapsulation, or bare |
Common failures
- Pressure or temperature rating below well conditions
- Tube material not suited to the fluids, for example 316 in sour service
- Damage while running in hole, or abrasion against the casing
Troubleshooting
- Symptom
- Gauge signal drops out after installation
- Likely cause
- Conductor or insulation damage during running
- What to check
- Insulation and continuity test from the outlet, compare with pre run records
- Symptom
- Gradual signal loss over months
- Likely cause
- Fluid entry through a breached tube or splice
- What to check
- Insulation trend, review tube material against the well fluids