Confined complex porous media have dominated the energy landscape in recent decades, particularly in the context of the shale revolution. These nanoporous porous media systems are extreme environments characterized by massive heterogeneity and a host of physical mechanisms at various spatio-temporal scales working in tandem to produce system-level behavior. Unlike classical geologic porous media, these extreme environments do not lend themselves to direct visualization and observation of flow, transport, and phase behavior of fluids. Due to the confinement effects, many of the available simulation modeling platforms fail to accurately capture the physics. Recent advances in computational modeling offer a solution to this seemingly intractable problem through mesoscopic simulation models that bridge microscale physical insights from molecular simulations to macroscale models via statistical representation of matter distribution in these confined and complex pore structures. This book begins with a brief review of the fundamentals of the lattice Boltzmann method, including classical boundary and intermolecular force treatments, and the associated esoteric unit conversion systems. It then continues with chapters dedicated to flow, transport, and phase behavior considerations for pure and binary mixtures in confined and complex systems. Subsequently, the book discusses high-performance computing and multiblock techniques to extend the models reach to much larger computational domains, aiming to elucidate the macroscale behavior of confined complex porous media. The book concludes with a discussion on the application of statistical learning techniques to push the boundaries of the models in terms of complexity and speed.