Evolution of Sandstone Porosity Through Time. The Modified Scherer Model: A Calculation Method Applicable to 1-D Maturity Modeling and Perhaps to Reservoir Prediction

摘要

Scherer's model of 1987 successfully predicted present-day porosities of sandstones using four factors: burial depth, stratigraphic age, quartz content, and degree of sorting. This model now has been modified to predict sandstone porosity through time in order to provide a better way to model sandstone porosity for 1-D basin modeling. The Modified Scherer Model (MSM) has many advantages over the depth-dependent Sclater- Christie (Athy) and Falvey-Middleton equations used for calculating porosity in 1-D modeling, because it predicts major differences resulting from age, sedimentation rate, sandstone composition, and pressure that are not considered in depth-dependent models. The only additional information required by the MSM is quartz content and Trask sorting coefficient. If these are not known, they may be estimated with reasonable confidence. The Modified Scherer Method could be added easily to existing software packages for 1-D modeling. It also may prove useful for making preliminary estimates of reservoir porosity (including timing of porosity loss), especially in early stages of exploration.