Reservoir Simulation

1. Whether the improvements in high-resolution three-dimensional imaging (algorithms that operate directly on digital images of field-scale reservoir rock materials) has really shifted the traditional qualitative modeling into quantitative modeling?

2. How exactly are we integrating pore-scale physics such as (microscopic) capillary-forces (IFT) and wettability (contact-angle) into reservoir-scale models through upscaling (numerical coupling)?

Can we perform pore-scale physics/chemistry on a sufficiently large domain in order to extract continuum-scale parameters?

If so, then, can we deduce the main continuum-scale parameter, i.e., relative permeability as a function of hysteresis, wettability, Capillary number, viscosity ratio, absolute permeability, saturation history, injection rate, wettability alteration, formation damage, stimulation and subsidence?

3. In the context of pore-to-continuum multi-scale techniques, although, boundary coupling links pore-scale models with adjacent continuum regions at an interface between the two, can it still upscale information across multiple length scales at the same location?

4. Whether hierarchical coupling (which links pore-scale and continuum-scale models in the same region) really address large disparities in both length and time scales?

Whether sequential coupling has really improved the predictive power of reservoir models, which makes use of pore-scale prediction of relative permeability (rather than using general empirical models)?

5. Why does pore-scale or gridblock-scale heterogeneity delay transport; and in turn, increase breakthrough times by up to an order of magnitude in comparison to that of the predicted results using a conventional advection-dispersion equation?

6. If overall saturation cannot be changed resulting from the differences in inflow/outflow, can LBM models be used to monitor the natural evolution of saturation history (given the constraint that LBM models employ periodic or mirror boundary conditions)?

7. In the context of multiscale modeling, pore-scale models derived from high-resolution imaging remain to be order-mm in size, while continuum-scale gridblocks remain to be three orders of magnitude larger.

If so, then, feasible to have unique length scales in coupled models?

[Also, the timescales for immiscible displacement in a mm-sized pore-scale model remain to be order seconds or even less than one second, while numerical time steps at the continuum-scale are orders of magnitude higher].

8. Whether the length scales used in the pore-scale modeling remain to be sufficient enough in order to extract spatially averaged continuum-scale parameters such as permeability, relative permeability and capillary pressure?

9. Whether the continuum properties within a gridblock remain to be reasonably uniform; and in turn, whether, the flow conditions remain to be such that the original continuum-scale equation remains valid everywhere?

Suresh Kumar Govindarajan

Professor (HAG)

IIT Madras

02-Sep-2024