Numerical Analysis of Geomechanical Behavior affected by Depressurization Conditions of Gas Hydrate Production in the Ulleung Basin, East Sea, Korea

Abstract

The production of gas hydrate using the depressurization method can lead to subsidence due to decreased strength and stiffness of hydrate-bearing sediments. Since subsidence could damage sea-bed facilities and production wells, it is essential to study this problem. In this study, geomechanical behaviors of hydrate-bearing sediments were predicted considering the properties of a field production test site in the Ulleung basin, East sea, Korea. For this purpose, subsidence and displacement velocity were analyzed according to the depressurization conditions. As a result, geomechanical behaviors mostly occurred in the upper hydrate-bearing sediments when the depressurization method was applied. In addition, the effect of bottom hole pressure was greater than that of depressurization rate. This study can be used as a basic data for field production tests in the Ulleung basin.