Experimental investigation and modelling of the hydrate formation kinetics based on hydrate pore-scale distribution in porous media

Hydrate technology has a bright future for innovations in water, energy, and environmental applications. A reliable and applicable kinetic model of gas hydrate formation is essential for developing hydrate technology. In this work, the experiments of methane hydrate formation with different water saturation SA are conducted in the Cubic Hydrate Simulator (CHS), where the pressure profile and temperature distribution are measured. A new kinetic model integrating hydrate pore-scale distribution is established, assuming that the reaction area AS is controlled by the aqueous phase surface area along the gas-soluble direction. This new model is employed to replicate the experimental process numerically by the history-matching method, and the intrinsic reaction rate constant K0 is determined to be 850.0 mol/m2/Pa/s. In addition, we quantitatively distinguish the characteristics of the water pore-scale distribution in the excess-water, cementing-water, and excess-gas environments. This new model is validated to be more excellent than those with four currently available models, and the sensitivities of the kinetic parameters are discussed in detail. The results show that the spatial distributions of the temperature T and hydrate saturation SH spatial distribution are heterogeneous in CHS due to the phase change heat and heat transfer effect. The excellent performance of history-matching processes in the hydrate formation kinetics gives us strong confidence in the reliability and accuracy of the new model. This provides reliable predictions and mechanistic understandings of hydrate formation kinetics in the porous media.