Some of the world’s most comprehensive studies of sedimentary outcrops – rocks which appear at the surface – can be used to help exploit present and future petroleum reservoirs.
Faults displacing red and buff coloured sandstones (Courthouse area, Mill Canyon, Utah, USA). The red sandstone is little deformed, whereas the overlying, buff, coarse-grained sandstone is highly fractured.
A good geological and petrophysical description of reservoir complexity (heterogeneity) forms the basis for optimum field development and maximising hydrocarbon recovery.
However, severe limitations are often imposed by relatively low seismic resolution, especially for deeply buried reservoirs, and by wide well spacing.
These constraints can be partly overcome by studying reservoir analogues – similar ancient sedimentary rocks which crop out on the Earth’s surface.
This involves gathering detailed information which can provide a better impression of inter-well complexity and fluid flow.
The method can also improve the credibility of geological modelling tools, most of which create ranges of statistical representations of a reservoir within a framework determined by well information.
Fieldwork has been carried out around the world, and as far afield as the Lajas outcrop in Argentina and South Africa’s Tanqua Karoo Basin.
Studies of both these areas have put StatoilHydro and its associates among the front runners for transferring and incorporating multidata/multimedia outcrop-based information into operational practice.
