Flow · Measurement
Orifice Meter Run
A straight length of pipe with an orifice plate held in a fitting. The plate makes a pressure drop that is used to calculate gas flow.
What it does
The most common way to measure gas at wells and batteries. Flow comes from the differential pressure, static pressure and temperature, calculated by the flow computer.
Basics
| Standard | AGA Report No. 3 (API MPMS 14.3) |
| Fittings | Flange union, or dual chamber to change the plate under pressure |
| Needs | Straight pipe upstream and downstream, or a flow conditioner |
| Plate | Sharp square edge, flat and clean |
Common failures
- Plate installed backwards
- Worn or bent plate edge
- Liquid carried into a gas run
Troubleshooting
- Symptom
- Gas volume drifts from the sales meter
- Likely cause
- Damaged, dirty or reversed plate
- What to check
- Pull and inspect the plate, check bore and orientation
- Symptom
- Erratic differential
- Likely cause
- Liquid slugs in the run
- What to check
- Check separator dump and level control upstream