This is the third of a three-part tutorial describing a workflow for evaluating unconventional resources including organic mudstones and tight siltstones. Part 1 reviewed the unique challenges and provided an overview of the proposed workflow (Newsham et al., 2019a). Part 2 described in detail the many components of the workflow and how they come together to determine the storage capacity of the reservoir (Newsham et al., 2019b). Part 3 links the petrophysical results to the production potential in terms of fractional flow and water cut and presents alternate cross-checks of the storage properties to validate the results.
As stated in the previous tutorials a key function that petrophysics provides is the estimation of accurate storage properties. The authors recognize there are numerous practical workflows to estimate the storage capacity of these complex systems and offer ours as a viable but not exclusive option. Keep in mind that the goal is to provide consistent, portable, hence, reliable estimation of hydrocarbon storage capacity, aka "Petrophysics CPR", as discussed in Part 2. This is especially relevant when discussing reserves and being able to defend the use of petrophysics as a "reliable technology" as defined by the US Securities and Exchange Commission. The SEC defines a "reliable technology" as "… a grouping of one or more technologies (including computational methods) that has been field tested and has been demonstrated to provide reasonably certain results with consistency and repeatability in the formation being evaluated or in an analogous formation (Sidle and Lee, 2010)." Numerous papers are available discussing the impact of the SEC definition and rules changes made in 2014 (Sidle and Lee, 2010, 2016; Lee, 2011; Glorioso and Rattia, 2011).
