Interpretation of Pressure‐Depth Data From Confined Underpressured Aquifers Exemplified by the Deep‐Basin Brine Aquifer, Palo Duro Basin, Texas

Abstract

Investigations of underpressured aquifers can be improved by accounting for factors that impede accurate interpretation of pressure‐depth plots. Poor data quality and distribution obscure true pressure‐depth trends. Plotted data may also be distorted by the hydrogeologic setting, i.e., the surface topography, the structural dip of the aquifer, and the potentiometric surface. In the Palo Duro Basin in the Texas Panhandle, distortions caused by the hydrogeologic setting are reduced by delineating regions having little variation in surface topography and in structural dip of the aquifer. Pressure‐depth plots for these regions vary considerably. The effects of the hydrogeologic setting on these plots were evaluated by computing pressure‐depth data for flow parallel to the structural dip of the aquifer in each region. By comparing regression lines through real pressure‐depth data with those through computed data, true hydrologic conditions could be distinguished from the misleading effects of the hydrogeologic setting on pressure‐depth plots.