Modern reservoir engineering needs a radical new approach as the present work-flow cannot, from a practical point of view, be inclusive of all the potential descriptions. The use of the 'Reservoir Geonome' concept is proposed as a new strategy to meet the following challenge. 'Geological models of reservoirs are growing in size by a factor of ten each year, whereas our ability to numerically simulate these is growing by a factor of two' - Killough (pers. com.). Nowadays, in order to capture the uncertainty in a field's development, it is not necessarily enough to simulate 100 realisations of one reservoir scenario. Asset development teams need hundreds of simulations for multiple scenarios in order to be able to asses the risk and opportunities for a single asset and to calculate the economic value added of an individual investment opportunity when added to a corporate portfolio. Studies have shown that performance outcome is related to geological complexity (Dromgoole & Speers 1997; Bos et al. 2001) and the benefit of reducing the parameter space to the minimum in order to make a business case. Regardless of the environment set by current oil prices, it is important to identify what are the really crucial parameters that need to be considered in field evaluations. These parameters might be drawn from the full range of the traditional upstream oil and gas disciplines: geophysics, geology, petrophysics, rock mechanics and engineering. A geoengineering approach (Corbett 1997) puts aside the traditional discipline groups in favour of concentrated, integrated effort in five cross-disciplinary sub-areas: architecture, properties, modelling, simulation, and management. In this cross-disciplinary team environment, it is possible to systematically explore various fundamental engineering problems, such as the effect of geological heterogeneity on flow performance; the effect of sandstone architecture on the seismic response; the relative contributions of stress and saturation changes to time-lapse seismic response through; and the well test response to a braided fluvial reservoir. To illustrate aspects of a geonomic approach we consider some of the simplified taxonomic classifications that can be used to map critical parameters in a systematic approach by considering specific cases within a global framework.