Surface · Flow Assurance
Hydrate Inhibitors
Methanol or glycol injected into the gas stream at the wellhead or ahead of a choke, so hydrates cannot form as the gas cools.
What it does
Thermodynamic inhibitors shift the hydrate curve to lower temperatures but need large volumes. Low dosage kinetic inhibitors delay hydrate growth at much smaller rates.
Basics
| Thermodynamic | Methanol, glycol |
| Low dosage | Kinetic inhibitors |
| Injection point | Wellhead, upstream of chokes |
| Trade off | Large volumes and logistics for methanol and glycol |
Common failures
- Injection stops during a cold shut in and a plug forms on restart
Troubleshooting
- Symptom
- Choke freezing or pressure drop growing across it
- Likely cause
- Hydrates forming at the choke
- What to check
- Confirm inhibitor flow and dose for the gas and water rates