Abstract
There have been many different approaches to quantifying cut-offs, with no single method emerging as the definitive basis for delineating net pay. Yet, each of these approaches yields a different reservoir model, so it is imperative that cutoffs be fit-for-purpose, i.e. they are compatible with the reservoir mechanism and with a systematic methodology for the evaluation of hydrocarbons in place and for the estimation of reserves. These different requirements are accommodated by basing the quantification of cut-offs on reservoir-specific criteria that govern the storage and flow of hydrocarbons. In so doing, particular attention is paid to the relationships between the identification of cut-offs and key elements of the contemporary systemic practice of integrated reservoir studies. The outcome is a structured approach to the use of cut-offs in the estimation of reserves. The principal benefits of a properly conditioned set of petrophysical cut-offs are a more exact characterization of the reservoir with a better synergy between the static and dynamic reservoir models, so that an energy company can more fully realize the asset value.
