This document discusses rock typing, which involves classifying reservoir rocks into unique units based on their depositional environment and subsequent diagenetic changes that result in distinct porosity-permeability relationships. The document outlines the rock typing methodology, which includes selecting key wells, identifying rock types in those wells, predicting rock types in uncored sections, and modeling rock type distribution between wells. The document also discusses common pitfalls in rock typing and provides an example case study where rock typing was used to investigate high water cuts during production.