Reservoir Dynamics Ltd conducts research and provides consultancy services on the topics of geomechanics, faults and fractures and their influence on fluid flow in oil and gas reservoirs. Our aim is to help operators to increase recoveries at lower cost by utilising better models and more data.. Conventionally, a dynamic model of a reservoir refers to the simulation of fluid flow within a static framework of rock (apart from a pore volume compressibility that is usually assumed to be homogeneous, isotropic and unchanging). In contrast, plentiful field evidence from worldwide reservoirs indicates that it is not only the fluid that moves during reservoir operations: the rock is also dynamic with small strains which are heterogeneous, anisotropic and focussed on faults, fractures and other discontinuities; this leads to time-varying properties, including permeability. This influence has been seen in production data whether or not the reservoir was characterised as "naturally fractured". Recognition of the involvement of additional physics in reservoir behaviour can lead to benefit for practical issues of well placements, injectivities, productivities, sweep efficiencies, short-term and longer-term forecasting and reservoir simulator history-matching. The technology is well-suited to mature fields, but lessons can be applied to green fields. One conceptual model is consistent with 3 independent sets of field observations.