Hydrate Management in Deadlegs: Hydrate Deposition Characterization in a 1‑in. Vertical Pipe System

Deadlegs are the pipe sections used for specific services in production and transportation of oil and gas, and they often encounter hydrate management challenges. Despite stagnant fluids in deadlegs, warm water vapor readily condenses on the cold pipe wall, resulting in a risk of hydrate blockages by deposition. Proper management of hydrates in deadlegs is therefore required for economic and safety reasons. Here, we discuss the development of an 1-in. vertical pipe system that is designed to study hydrate deposition from water saturated gas. From a series of hydrate formation and dissociation, the hydrate deposits are characterized to obtain gas/water consumption, thickness/volume hydrate deposit distribution, hydrate morphology, and hydrate porosity and wetness. These characteristic properties are correlated with the header temperature and the time duration for hydrate deposition. Qualitative and quantitative information obtained from the present study contribute to our understandings of hydrate deposition and give insight into establishing management strategies to avoid or minimize the risk of hydrate deposition in deadlegs in oil and gas production and transportation systems.