A repeated theme regarding the Permian Basin in West Texas and Southeastern New Mexico in recent years is the concern over water. Drilling and completions operations require tremendous amounts of water, which, in an arid environment, is a large concern for oil and gas companies and other stakeholders. Normally, freshwater (water with a low content of total dissolved solids, or TDS) is used to create drilling fluids and completion fluids; however, in an effort to conserve freshwater, operators in the Permian Basin are being driven to utilize alternative water sources, such as brackish water (water with a higher TDS content). Using alternative water sources when possible is a step in the right direction towards protecting the freshwater resources of the region, but more is needed in order to ensure there will be freshwater available in the future.
The accumulation of salt in the pits would remain as a threat to the land surface and the underlying fresh water aquifer.
Drilling wastes in the Permian Basin contain high salt contents. Salts, generally chlorides, are encountered downhole, and often come to the surface during drilling, completions, and production operations. In order to control the osmotic pressure and stabilize the wellbore, salt is often added to the drilling fluids. Salts that are dissolved in fluids (drilling fluids, completions fluids, and produced water) can often be managed through injection below the freshwater aquifer; however, solid drilling wastes, such as drilled cuttings, are often managed at the surface in reserve pits. Drilled cuttings in the Permian Basin often contain chloride contents over 100,000 mg/kg. Closure methods for these pits vary, but one common method is to simply bury the cuttings on-site. Even though water-based cuttings often do not contain organic constituents such as TPH, the salts that they contain can migrate to groundwater over time. According to the Texas Water Development Board, “the accumulation of salt in the pits would remain as a threat to the land surface and the underlying fresh water aquifer,” and “chlorides often occur in ground water in the local vicinity of areas that were used to dispose of brine in unlined surface evaporation pits” (Ashworth et al., 1989. “Evaluation of Ground-Water Resources in Parts of Midland, Reagan, and Upton Counties, Texas.” Texas Water Development Board, Report R312).
Salts no longer have to be an Achilles heel for the industry.
Chlorides and other salts, such as those encountered during drilling operations, are highly soluble in water and can move rather freely through the environment. Chlorides persist in the environment, and there are no known natural processes to break them down over time. Without proper management, the salt contained within the reserve pits in the Permian Basin will eventually migrate to the water table, increasing the overall salinity and TDS of the aquifer(s). Fortunately, there are legitimate ways of managing drilling wastes to limit or eliminate potential threat of groundwater contamination. Scott Energy has been managing drilling wastes for more than 24 years, and has developed methods to manage drilling waste that can protect the environment and increase sustainability. Salts no longer have to be an Achilles heel for the industry.
This article was written by Jeffrey Tyson, Corporate Sales Executive for Scott Energy Technologies LLC. Copyright 2018 Scott Energy Technologies LLC.