Empirical Prediction of Porosity and Permeability in Sandstones

BLOCH, S., ARCO Oil and Gas Company, Plano, TX

Mean porosity and permeability of many sandstone intervals can be predicted prior to drilling. The predictive technique involves use of multivariate regression equations derived from calibration data sets. The effectiveness of this technique is illustrated by case studies, including several predrill porosity and permeability predictions.

The critical independent variables controlling porosity (dependent variable) are detrital composition, sorting, time-integrated temperature history, and time-integrated pressure history. In sandstones with a high content of detrital quartz and chert, grain size may also affect porosity. Permeability can be expressed by the same parameters as porosity. Most important, the independent variables that correlate with porosity and permeability can be often estimated prior to drilling from facies models and seismic data. Accurate predictions are not limited to sandstones containing only primary porosity. The predictive applicability of the empirical approach is constrained by the limits imposed by the calibration data set.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)