Downhole · Well Testing
Tester Valve
The downhole shut in tool in the drillstem test string that opens and closes the well at the bottom.
What it does
Opening it starts a flow period and closing it starts a buildup. Closing the well at the bottom minimizes afterflow, which makes the buildup easier to analyze. It is operated from surface.
Basics
| Operated | From surface |
| Controls | Flow and shut in periods |
| Benefit | Less afterflow, earlier radial flow |
Common failures
- Valve that does not seal when closed, so the buildup data is lost
Troubleshooting
- Symptom
- Pressure does not build during a planned shut in
- Likely cause
- Valve not fully closed
- What to check
- Repeat the closing sequence before continuing the test