Recycling Produced Water in the Permian Basin

Abstract

The rapid increase of oil exploration through hydraulic fracturing in the Permian Basin in western Texas is associated with production of large volume of wastewater containing potentially hazard chemicals. The wastewater is derived from water that is co-extracted with oil called “produced water.” The management and disposal of the wastewater generated from unconventional oil and gas exploration are the most challenging topics given their low quality and potential environmental and human health risks. Unconventional oil wastewater is even more critical in western Texas where the water availability is limited. Oil wastewater in Western Texas is injected through deep-injection wells to the subsurface as a common disposal practice. Yet local companies are seeking to find ways to recycle oil wastewater for reuse for hydraulic fracturing or possibly other beneficial use. This Master Project investigates the water quality of produced waters generated from the unconventional oil exploration in the Permian Basin and the treated water generate from a treatment site. As part of this study 15 water samples were collected at the Chiltepin Recycling Plant in Pecos, Texas, prior and after treatment that involved temporary storage of the oil wastewater in open reservoir that is managed with a continuous treatment of aeration to the pit. Water samples were analyzed at Vengosh Lab in Duke University for major elements and dissolved organic carbon (DOC). The data show that the Permian produced water is highly saline (chloride up to 27,000 mg/L, 1.4 time the salinity of seawater) with high concentrations of ammonium (175 mg/L), boron (50 mg/L), and DOC (220 mg/L). This water quality infers that disposal or leaking of the Permian wastewater to the environment would cause major damage to the ecological system and contamination of water resources. The data show that the water quality of the treated water is indistinguishable that untreated and thus the recycling process in the site does not reduce the salts and contaminants potential of the Permian produced water.