Reduced Numerical Model for Methane Hydrate Formation under Conditions of Variable Salinity. Time-Stepping Variants and Sensitivity

Abstract

Abstract:In this paper, we consider a reduced computational model of methane hydrate formation in variable salinity conditions, and give details on the discretization and phase equilibria implementation. We describe three time-stepping variants: Implicit, Semi-implicit, and Sequential, and we compare the accuracy and efficiency of these variants depending on the spatial and temporal discretization parameters. We also study the sensitivity of the model to the simulation parameters and in particular to the reduced phase equilibria model.

Methane Hydrate Formation in Ulleung Basin Under Conditions of Variable Salinity: Reduced Model and Experiments

“…In fact, rigorous analysis of the diffusive transport model of methane was first given in Gibson et al (2014), followed by more general analysis in Peszynska et al (2015) for the advective/diffusive transport. The NCC-MS approach enables various variants of numerical discretization and of time-stepping discussed in the second paper Peszynska et al (2016).…”

“…The companion paper Peszynska et al (2016) gives details on how (2f) is implemented in the numerical solver. Below, we discuss the data for χ max LM .…”

“…We use operator splitting and treat advection explicitly and diffusion/equilibria implicitly, in several variants of time-stepping applied to the coupled methane-salt system. Details and sensitivity studies are provided in the companion paper Peszynska et al (2016).…”

“…In fact, we find that it is positive, in contrast to the model (7c). In the companion paper Peszynska et al (2016) we discuss the sensitivity of simulations to the particular value and to the sign ofB.…”

“…In contrast to Torres et al (2004) and consistently with Liu and Flemings (2008), our model fits in the general framework of multiphase multicomponent models such as those in Lake (1989) and Class et al (2002), and implements bona fide equilibrium phase constraints known from thermodynamics (Sloan and Koh 2008;Davie et al 2004), albeit in an approximate manner. In the companion paper Peszynska et al (2016) we present details of numerical discretization with a particular emphasis on the variants of the time-stepping, which are enabled by the approximations proposed here.…”