Geology · Exploration
Anticline Trap
An arch shaped fold in the rock layers. It makes a good trap when reservoir rock lies in its core under impermeable seal layers.
What it does
Oil and gas fill the fold down to the spill point, the structurally lowest point that can still hold them. Once full, the excess spills and keeps migrating until another trap catches it.
Basics
| Type | Structural trap (fold) |
| Fills to | Spill point |
| Needs | Reservoir in the core, seal in the outer layers |
Common failures
- Closure smaller than mapped, so the trap holds less than estimated
Troubleshooting
- Symptom
- Less pay than expected
- Likely cause
- Structure or spill point mapped wrong
- What to check
- Remap the structure with the well data before appraisal