This paper summarizes historical advancements in low-dosage hydrate inhibitors (LDHIs) over the past 2 decades, discusses their advantages and limitations, and their selection criteria. Historically, hydrate risk has been managed by keeping fluids warm, removing water, or injecting thermodynamic hydrate inhibitors (THIs), commonly methanol (MeOH) or monoethylene glycol (MEG). THIs require high dosage rates; therefore, that technique can pose limitations to production systems in the form of supply, storage, and umbilical-injection constraints. Additionally, high dosages of MeOH can cause crude contamination for downstream refineries. LDHIs continue to offer significant efficiency and cost benefits over other techniques.
Introduction
THIs have long been used by the industry because of their ability to shift the hydrate-equilibrium curve toward higher pressures and lower temperatures by changing the activity of water molecules.
