Matt Balhoff University of Texas at Austin Flow and transport in subsurface media are affected by phenomena at various spatial scales, from nanometers to kilometers. Small-scale modeling at the pore level is a rigorous approach to simulation of fundamental flow behavior, but large-scale reservoir simulators require macroscopic inputs. Pore-scale modeling has become an effective method for accurate prediction and upscaling of macroscopic properties in porous media. Advancements in imaging have allowed the development of digital media that accurately represent the original rock sample. Likewise, advancements in computational methods have allowed for more accurate (and faster) pore-scale simulations. Pore-scale modeling approaches are often quantitative and predictive and in many cases these models are able to serve as surrogates of experimental results of permeability, tracer tests, capillary pressure curves, and relative permeability curves. In this talk, methods and challenges for pore-scale modeling will be discussed. Computational and imaging restrictions generally limit the size of pore-scale models to the order of 1.0 mm3. These models are often not large enough to capture the petrophysical properties of the entire medium and inaccurate results can be obtained when upscaling to large-scale reservoir simulators. Here, we will discuss in detail the challenges associated with upscaling and multiscale simulation as well techniques for addressing these challenges.