Various empirical observations have been made regarding the nature of the distribution of shale productivity and the potential existence of three dependent intervals that seem to separate the uneconomical wells from the average and good wells. The areas of good well productivity exhibit a log normal distribution and seem to be controlled mainly by the natural fracture system. These differences in performance seem to be related mostly to the shale capacity defined as the product of four key shale drivers: TOC, porosity, brittleness, and fracture density. When drilling a shale reservoir, it appears that the Relative Intercepted Shale Capacity (RISC) seems to have a strong correlation with the resulting relative well performance. Consequently, well productivity could be predicted in a relative sense with reasonable accuracy if the 3D shale capacity model is available to the operator. Having such a 3D model available, a shale operator can compute the RISC of his future wells and adjust their landing zone, azimuth and length accordingly to reduce drilling and fracing costs, to achieve the best return on investment and accelerate the time to payout.

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