Local characterisation of fluid flow in sandstone with localised deformation features through fast neutron imaging

Abstract

Understanding fluid flow through rocks is of key interest in hydrocarbon production and CO2 sequestration, amongst other applications. Such fluid injection or extraction from subsurface reservoirs can be significantly modified (increased or decreased) by deformation and in particular by localised deformation features (fractures, shear bands and compaction bands). How such deformation alters fluid flow is however not well characterised experimentally. Measurement of fluid-flow distributions throughout a specimen requires techniques that can, first, see inside a test specimen and, second, see the fluid distinctly from the solid part. Therefore, neutron absorption imaging is well adapted to fluid flow monitoring in rocks as water is largely opaque to neutrons (i.e., it is highly absorbing) and rocks are generally less absorbing. In this paper we present initial results of neutron radiography monitoring of fluid-flow through samples of a sandstone containing localised deformation features (shear-bands). A comparison of flow through an intact specimen and flow through samples containing localised deformation features is presented that provides insight into the effect of localised deformation on the flow properties.