Scientific questions addressed and environmental impacts addressed. The properties of fluids when confined at the nanometre scale are significantly different from the properties of the correspondent macroscopic bulk fluid. Changes in phase behaviour, structural and transport properties are commonly observed under confinement. This is a consequence both of the small size of the system and of the interactions with the wall of the material confining the fluid. Molecular simulations can be very useful in elucidating confinement effects and the underlying mechanism responsible for the observed behaviour. We employed classical Molecular Dynamics (MD) and Monte Carlo (MC) simulation techniques to study the structural and transport properties of two systems relevant to the shale gas upstream sector: (a) Water-based fracturing fluids confined in nano- and meso-pores of clay minerals (kaolinite, montmorillonite, muscovite) - major components of Xxxxxxx shale in the UK; (b) shale gas confined in mature type II kerogen (the insoluble part of organic matter found in shales that hosts the natural gas to be extracted). Results obtained form the simulations include preferential distribution in heterogeneous pores, diffusion coefficients, effects of fluid composition and porosity on diffusion coefficients of the fluid components. Shale gas technology has being developed during the last three decades and it has been revealed that no two shales are the same. Therefore, the development of a shale formation into a productive reservoir requires customized design, through the adaptation and optimization of existing technologies. One of the major challenges faced by the industry is the rapid decay of production, which is associated with small recovery of the shale gas ‘in place’. While hydraulic fracturing allows the recovery of an amount of gas that was originally inaccessible, the factors governing the transport of gas to the fractured clay matrix through the organic matter nanopores are still not well understood. The results of our molecular simulations will help to optimize and improve the extraction processes. Currently, North America is the only major shale gas-producing region. This is partly attributed to environmental concerns associated with the extraction process in other parts of the world. Among other issues, there are concerns regarding the potential migration of naturally occurring radioactive materials (NORMs). The study of the NORM transport in confined fracturing fluid and their adsorption behaviour in the heterogeneous clay por...
