Multi-rate time stepping schemes for hydro-geomechanical model for subsurface methane hydrate reservoirs
For researchers modeling subsurface methane hydrate reservoirs, this work provides two new computational schemes that trade off speed and robustness, though the improvements are incremental.
This paper presents two multirate time stepping schemes for hydro-geomechanical models of methane hydrate reservoirs, evaluating their speed-up and accuracy against an iteratively coupled scheme. The semi-implicit method offers higher speed-up but is sensitive to time scale ratios, while the compound-fast method is more robust but yields lower speed-up.
We present an extrapolation-based semi-implicit multirate time stepping (MRT) scheme and a compound-fast MRT scheme for a naturally partitioned, multi-time-scale hydro-geomechanical hydrate reservoir model. We evaluate the performance of the two MRT methods compared to an iteratively coupled solution scheme and discuss their advantages and disadvantages. The performance of the two MRT methods is evaluated in terms of speed-up and accuracy by comparison to an iteratively coupled solution scheme. We observe that the extrapolation-based semi-implicit method gives a higher speed-up but is strongly dependent on the relative time scales of the latent (slow) and active (fast) components. On the other hand, the compound-fast method is more robust and less sensitive to the relative time scales, but gives lower speed up as compared to the semi-implicit method, especially when the relative time scales of the active and latent components are comparable.