Chemical modeling of the rock-water interactions in the Upper Almond Sandstone within the context of burial (thermal) history of these rocks predicts the petrographically observed sequence of cementation to a fair degree.

The depositional environment of the Upper Almond Sandstone is believed to have been a barrier bar of Late Cretaceous age. Therefore, initial pore-water chemistry is assumed to be a function of seawater composition and, consequently, marks the starting point of diagenesis.

Present-day water compositions along with a knowledge of depositional environment assist in further deduction of early pore-water composition as one-third diluted seawater. Formation waters collected from the Upper Almond Sandstone in the Wamsutter area are distinguished from waters of the underlying Main Almond Sandstone on the basis of total dissolved solids, ¹⁸O, log-derived salinities, and pressure-depth profiles.

The main objective of this study was to test the predictive capability of the existing computerized chemical modeling approach to elucidate diagenesis in the Upper Almond Sandstone. Having noted the chemical processes leading to the simulation of the observed diagenetic sequence, one can follow a similar logic to explore deeper or shallower for similar lithologic units.