From Source Rock to Reservoir: The Evolution of Self-Sourced Unconventional Resource Plays

From a geological perspective, the exploration of shale source rocks is relatively straightforward. Advances in stimulation technologies, such as hydraulic fracturing, have made it possible to economically extract hydrocarbons, both liquid and gas, from their respective source rocks. However, the devil is in the details when it comes to "sweet spotting" which shale reservoirs are going to be the best producers. Organic-rich shales are fine grained and tend to be petrophysically challenging and mineralogically and geochemically heterogeneous on the nanoscale. The advent of focused ion beam - scanning electron microscopic (FIB-SEM) techniques now allows us to image the pore networks in the organic matter that generated the hydrocarbons we produce. Two types of pore networks exist in organic-rich shales. One type is water wetting and is associated with the inorganic component of the shale, mostly clays. The other pore network is hydrocarbon wetting and is associated with the porosity that develops in organic matter during maturation and hydrocarbon generation.