Interpretation of chemical composition of subsurface brines based on mixing and dilution from the Chazy Limestone and Copper Ridge Dolomite in Morrow County, Ohio
Loading...
Date
1994-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
The Ohio State University
Abstract
The chemical compositions of five oilfield brine samples from the Chazy Limestone and the Copper Ridge Dolomite can be explained as the result of two independent brines mixing in the subsurface. Element concentrations were affected by dilution from meteoric water or groundwater. The two end member brines identified in this study are characterized by high concentrations of Na and Ca, respectively. Sodium concentrations decrease with depth while calcium concentrations increase with depth. These results support previous findings that Ca-rich brines in Ohio originate at relatively greater depths. The Ca-rich brine migrated toward the surface until it mixed with the Na-rich brine. The brines are separated by a shaley layer between two reservoir rocks, thereby constraining the mixing process to a relatively slow rate.