Average-porosity distributions in the Wolfcamp deep-basin aquifer are critical to discernment of the geographic trends in effective-porosity in the Palo Duro basin. Precise data are used to improve resolution of porosity values for computer-simulated areal ground-water modeling. Assessing vertical distributions of lithology and porosity in each well studied involves analysis of crossplotted neutron- and density-porosity log responses. This method more accurately identifies lithology and porosity than does the commonly employed crossplotted neutron-porosity and sonic (interval traveltime) responses. Log-derived average-porosity distributions yield information about effective pore volume (i.e., movable water) in the Wolfcamp aquifer and enhance the accuracy of estimates of raveltimes and velocities of brines in basinwide traverses. Mathematical analysis of average traveltime and total effective pore volume yield estimates of the rates of annual discharge from the Wolfcamp aquifer in the Palo Duro basin. Based on average flush rates between 2.2 and 1.5 m.y., annual discharge rates from the Wolfcamp aquifer, across the northern and eastern basin boundaries, are about 3.6 × 10⁵ m³ year^-1 to 5.3 × 10⁵ m³year^-1.

End_of_Article - Last_Page 465------------