Estimation of model parameters and properties for numerical simulation on geomechanical stability of gas hydrate production in the Ulleung Basin, East Sea, Korea

Abstract

The process of hydrate dissociation and production induced by depressurization incorporates intricate hydraulic, thermal, and mechanical phenomena. Thus, coupled thermal-hydraulic-mechanical (T-H-M) simulation is critically necessary to evaluate the geomechanical stability of hydrate production in hydrate-bearing sediments (HBS). However, methods of estimating the input model parameters and properties of the target reservoir, in particular in unconsolidated marine sediments, have received limited attention compared to studies on production simulators. The T-H-M properties of the marine sediments change considerably with depth, geological strata, and soil type of each layer. Therefore, it is important that representative layers and their corresponding T-H-M properties should be properly estimated to analyze the stability and productivity of methane gas recovery in the field. This study provides a comprehensive estimation for the model parameters and properties of unconsolidated marine sediments, based on vast data from field seismic surveys and laboratory experimental results with core samples, investigates empirical correlations between model parameters and methane hydrate saturation, and finally summarizes the estimated model parameters and properties, which can possibly be applied to on-going numerical research into stability assessment of the pilot gas hydrate (GH) production test, which is soon to be performed in the Ulleung basin.