Hydrate decomposition and its influence on cement sheath strength in cementing process

Abstract

This study investigates the impact of gas hydrate decomposition on cement sheath integrity in deepwater wells encountering gas hydrate-bearing sediments (GHBS) using a novel coupled TOUGH + HYDRATE (T + H) and Particle Flow Code (PFC) model. The model simulates cement penetration, hydrate decomposition, and reverse invasion fluid migration, quantifying the collective effects on sheath integrity through crack development. Parametric studies show that hydrate dissociation extended up to 0.20 m, increase the cement sheath crack ratio by up to 40.64 %, and reduce compressive strength by up to 56.5 %. These findings evaluate the physical responses of the sediment-cement system under varying conditions, providing key insights for optimizing cementing strategies in GHBS.