In order to demonstrate the potential use of geochemical modeling using nonequilibrium, coupled reaction-transport codes in predicting reservoir quality, we have carried out simulations of four generalized systems using the REACTRAN computer code. The systems chosen contained "clean" and "dirty" arkoses and were subjected to alteration by fresh and saline waters at a constant temperature of 110°C. We show the results of these simulations at various times during the first 10 million years of diagenesis and describe the salient geochemical features leading to the spatial and temporal distributions of authigenic minerals.

The timing and extent of diagenetic events simulated here is a function of initial rock composition, the rate of fluid flow, and the rates of mineral dissolution and precipitation assumed here. When appropriate rate data is included as a function of temperature and pH, one anticipates a good comparison of simulated and observed diagenetic events. The prediction of the timing and the extent of diagenetic events is the key to the prediction of reservoir quality.