Chloride concentration gradients in tank-stored hydraulic fracturing fluids following flowback [report]

Pamela J. Edwards, Linda L. Tracy, William K. Wilson
2011 unpublished
A natural gas well in West Virginia was hydraulically fractured and the fl owback was recovered and stored in an 18-foot-deep tank. Both in situ fi eld test kit and laboratory measurements of electrical conductivity and chloride concentrations increased substantially with depth, although the laboratory measurements showed a greater increase. The fi eld test kit also underestimated chloride concentrations in prepared standards when they exceeded 8,000 mg L -1 , indicating that laboratory
more » ... or other more accurate methods of detection should be used to determine chloride concentrations in fl owback when they may be approaching West Virginia regulatory levels (12,500 mg L -1 ) that disallow disposal by land application. The gradation of chloride with depth also has implications for procedures used to collect fl owback samples from reserve pits or tanks before disposal to ensure the resulting composite chloride concentration is representative of the total volume. Cover Photo William Wilson uses a fi eld kit to determine the chloride concentrations of a fl owback sample. Photo by Pamela Edwards, U.S. Forest Service. The use of trade, fi rm, or corporation names in this paper is for the information and convenience of the reader. Such use does not constitute an offi cial endorsement or approval by the U.S. Department of Agriculture or the Forest Service of any product or service to the exclusion of others that may be suitable.
doi:10.2737/nrs-rp-14 fatcat:j7rg7wivtfdaxllbt2v2w3pfru