A Tiered Approach to Evaluating Salinity Sources in Water at Oil and Gas Production Sites

Authors: S. Paquette, L. Molofsky, J. Connor, K. Walker, H. Hopkins, A. Chakraborty
Published: April 2017 in Ground Water.

Abstract

A suspected increase in the salinity of fresh water resources can trigger a site investigation to identify the
source(s) of salinity and the extent of any impacts. These investigations can be complicated by the presence
of naturally elevated total dissolved solids or chlorides concentrations, multiple potential sources of salinity, and
incomplete data and information on both naturally occurring conditions and the characteristics of potential sources.
As a result, data evaluation techniques that are effective at one site may not be effective at another. In order to
match the complexity of the evaluation effort to the complexity of the specific site, this paper presents a strategic
tiered approach that utilizes established techniques for evaluating and identifying the source(s) of salinity in an
efficient step-by-step manner. The tiered approach includes: (1) a simple screening process to evaluate whether an
impact has occurred and if the source is readily apparent; (2) basic geochemical characterization of the impacted
water resource(s) and potential salinity sources coupled with simple visual and statistical data evaluation methods
to determine the source(s); and (3) advanced laboratory analyses (e.g., isotopes) and data evaluation methods to
identify the source(s) and the extent of salinity impacts where it was not otherwise conclusive. A case study from
the U.S. Gulf Coast is presented to illustrate the application of this tiered approach.