Numerical Simulation on Sand Production Based on Laboratory Gas Hydrate Production Experiment

Abstract

Gas from natural gas hydrate (NGH) is priced competitively with gas prices. Most marine NGH is stored in low cementing strata, which easily cause sand production problems, restricting the commercial production and environmental safety of NGH’s development. This study applied a numerical simulation on sand production in hydrate-bearing sediments’ (HBS) exploitation. The numerical simulation on sand production was carried out for different productions of laboratory NGH exploitation. The results show radial strain appeared to be deformed away from the wellbore and show radial displacement close to the wellbore during mining. Due to the overburden stress condition, the boundary condition wall was a displace less rigid body. The radial displacement was greatly affected by depressurization, which showed the displacement to the wellbore and sanding. The radial strain was dominant by the shear shrinkage phenomenon in the mechanical model, while the reservoir’s radial displacement was away from the wellbore instead. The balance between the fluid driving force of production rates towards the wellbore and radial displacement drawing away from the wellbore is significant to sand production in HBS. The dominant forces of sanding were different mechanical and hydraulic combinations in three periods of GH production.

Keywords

• gas hydrate
• hydrate-bearing sediments
• sand production
• numerical simulation