Effects of hydraulic model on gas productivity and geomechanical stability during methane hydrate production by depressurization

Abstract

The permeability of hydrate-bearing sediments is a key parameter in assessing the methane gas productivity as it generally varies with the hydrate saturation. Numerous hydraulic models have been suggested to correlate the hydraulic conductivity and hydrate saturation in sediments. Moreover, various numerical simulators have been developed to investigate the gas productivity in field production tests. The K-hydrate simulator was developed to analyze the potential of pilot production of gas hydrates in the Ulleung basin, East Sea, Korea. In this study, an empirical hydraulic model for the Ulleung basin was derived and applied to a simulator using the experimental results from disturbed field specimens. Production test simulations were performed considering the newly obtained hydraulic model, the depressurization method, and a production period of 14 days. The simulation results accurately represent the gas and water production rates over production time and vertical displacements in the vicinity of the production well.