Flow Assurance Technical Section

Chapter 15 of the Subsea Engineering Handbook alludes  to salt, methanol and glycols acting as thermodynamic hydrate inhibitors that shift the hydrate stability curve. Is it possible to rely on just the presence of high salinity produced water to effectively suppress hydrate formation and eliminate the need for methanol or glycol injection? Are there any case studies out there demonstrating this? Are there system performance differences in a gas system vs a multiphase system? In trying to simulate the effects of high salinity water on hydrate formation what equation of state property package should be used in a process simulation?

thank you

Hi,

high formation water salinity can help to reduce hydrate risk, but couple factors need to be considered:

• is the formation water salinity high enough to shift the operation envelope out of hydrate domain?
• what is the uncertainty on formation water salinity?
• for gas field, how much is the condensed water from gas phase?

There are some fields in GoM have high formation water salinity, not sure if there is any published paper on the topic, but as FA engineers, we always take into consideration the formation water salinity when assessing hydrate risk.

hope this answers part of your questions.

regards,

Suyu