As exploration moves into deeper, depositional or tectonically-complex new frontiers, simple and conventional reservoirs are getting scarce. Despite the spectacular advances in seismic and log acquisition and interpretation, the risks involved in the exploration of new, deeper, depositional, tectonic or diagenetically-complex prospects remain large. 3D and 4D models incorporating sophisticated structural, thermal, generation and migration histories help to reduce exploration risks in new and tectonically complex settings, but they simply lack information on an essential part of petroleum systems: the reservoir.
Most new prospects represent clastic, carbonate or other, unconventional reservoirs with strong diagenesis. For these, the conventional, indirect evidence of texture and composition provided by logs and conventional, simplified petrographic descriptions is simply not enough. Undiscovered and unproven hydrocarbon reserves are contained either in conventional clastic and carbonate reservoirs with strong diagenesis, such as the deep Gulf of Mexico and the eastern Brazilian margin basins, or in unconventional plays, such as by tight sands, gasshales and coalbed methane. As a matter of fact, about 35% of the technically recoverable reserves in the U.S. lie in unconventional reservoirs.
There is an emerging trend for the integration of systematic petrographic analysis with petrologic, geochemical, wireline log, petrophysical and seismic analysis, in order to tackle the challenges involved in the reduction of the exploration risks and optimization of the development and production of such reservoirs.
There is an emerging trend for the integration of systematic petrographic analysis with petrologic, geochemical, wireline log, petrophysical and seismic analysis, in order to tackle the challenges involved in the reduction of the exploration risks and optimization of the development and production of such reservoirs.