Reservoir and Downhole Numerical Simulation

Dear Colleagues,

Reservoir simulation has come a long way since the early black-oil models of the 1970s, yet many of the questions we ask of our simulators today are surprisingly similar to those engineers asked back then: how much oil can we recover, how should we place wells, what happens if we change the injection strategy? We can now answer these with far more detail and richer physics, but anyone who has history-matched a difficult field knows the gap between a simulation result and a confident decision remains wide.

Reservoirs are mostly heterogeneous, and our models depend on data that is sparse and interpreted through assumption. Two engineers can build different geological models from the same dataset and match production history with both, which is why history matching under uncertainty and ensemble-based methods matter: they give a more honest view of what we know.

The physics simulators must handle also keeps expanding, from unconventional reservoirs and EOR to CO₂ sequestration, hydrogen storage, geothermal projects, and downhole physics increasingly modeled alongside the reservoir.

This Special Issue on "Reservoir and Downhole Numerical Simulation" welcomes new numerical methods, case studies, history-matching exercises, and field applications. Contributions sharing code or data are especially encouraged, as reproducibility remains a weak point in our community.

Topics include, but are not limited to, the following:

• Black-oil, compositional, and thermal reservoir simulation.
• Simulation of unconventional reservoirs, including shale, tight gas, and heavy oil.
• Enhanced oil recovery: chemical, miscible gas, thermal, and hybrid processes.
• Coupled flow and geomechanics, including fractured and stress-sensitive reservoirs.
• Pore-scale and dual-continuum approaches to complex rock systems.
• Wellbore and downhole modeling, including multiphase flow and inflow control.
• History matching, uncertainty quantification, and ensemble-based methods.
• CO₂ storage, underground hydrogen storage, and geothermal reservoir modeling.
• Numerical methods, gridding, upscaling, and high-performance computing for reservoir simulation.
• Machine learning and data-driven approaches as complements to physics-based simulation.

Thank you, and I hope you will consider contributing to this Special Issue.

Dr. Ahmed Alsubaih
Dr. Zhanglei Fan
Dr. Yang Zhao
Dr. Shizhong Zhang
Guest Editors

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