Unconventional Plays Integrated Reviews
The assessment methodology (IADs) and production practices of conventional reservoirs vary from those used for unconventional resources (i.e Ultra- Deep Fractured, Fractured Gas Shales, Coalbed Methane and Tight Gas sands). Predicting productivity of offsetting well locations in a non conventional reservoir environment are one of the key challenges to enhance well placement strategy and to meaningfully differentiate the quality of a each drainage point.
In many cases, none of the conventional reservoir architectural drivers correlate strongly to well performance. There may be not a unique reliable spatial predictor of conventional reservoir variables (even if the measurements and tests required to estimate these variables have been executed) to enhance prediction of performance on unconventional environments.
However, Shale Petrophysics that includes the exhaustive integration of Core Lithofacies, Geochemically derived TOC Content, Free and Adsorbed Gas Analysis and Critically Stressed Fracture Analysis have proven to have established the basis to predict well performance at the well scale.
At a play scale though, performance may nonetheless display a wide variability; and it is often the case that such variability cannot easily be predicted in advance or even correlated to conventional measurements (e.g. porosity, thickness, structural position, etc.).
That is why, in many instances, non conventional plays have alternately been described as “statistical” plays in which an operator must drill a large number of wells and can expect fairly repeatable results if enough wells are drilled. Under that scenario the economic development of unconventional resources is often questionable.
This hurdle can be minimized by an integrated interpretation of largescale architectural reservoir attributes (Reservoir compartmentalization, fractures, and faulting) obtained from leading edge seismic processing and interpretation technics.
The obtained geological framework and the resulting elements from single well petrophysics define the areas of higher concentration of reservoir properties and other building elements of the reservoir systems such as seals, and baffles controlling fluid distribution and flow in the resrvoir.