A novel semi-analytical approach for modeling multiphysics coupling throughout the entire exploitation process in methane hydrate-bearing sediments

Abstract

Methane hydrates are attracting attention as a promising energy source. However, accurately simulating the multiphysics dynamics during the entire exploitation process remains a significant challenge. In this study, the complete process of drilling, casing and production was examined, and an efficient semi-analytical model was proposed to couple the seepage, temperature, hydrate dissociation, and mechanical field around the vertical production well. The model integrated permeability, heat transfer and mechanical parameters that are dependent on hydrate saturation. Additionally, factors such as gas and water production, heat absorption due to hydrate dissociation, and mechanical response of the reservoir under loading and unloading stress paths were also considered. The accuracy and practicality of the model were validated by comparing computational results for depressurization-based exploitation with those generated by the researcher's own numerical model and various numerical simulators developed by other researchers. The proposed model was also found to be computationally efficient. The model was used to simulate a range of depressurization strategies and depressurization combined heat injection schemes, and recommendations were made based on the outcomes of these simulations to enhance the safety and efficiency of hydrate exploitation.