Over the recent past, hydraulic fracturing processes have been the subject of increasing scrutiny of the chemistries and processes employed, with particular concern directed towards protection of water resources. For example, operators and fracturing services companies in the United States have been targeted by both federal and state legislators and the Environmental Protection Agency (EPA) with audits, inquiries, Congressional hearings, and subsequently, new regulations requiring full public disclosure of the chemicals pumped in fracturing treatments and controlling the use of certain chemistries, such as diesel oil. Much effort has been expended to identify alternative, more environmentally acceptable products which maintain the needed material performance characteristics and cost basis.
A new quantitative process to evaluate and rank the hazards posed by various treating additives and potential alternatives was presented in SPE135517. The process is based upon the Globally Harmonized System for Classification and Labeling of Chemicals (GHS) which has been adopted by the United Nations to standardize information about communication of the hazards and toxicities of chemicals. After the respective material hazards have been quantified, they may be ranked for comparison with like-purposed additives for their anticipated safety, health, and environmental impact. Then, the best candidates by that measure can be assessed for performance and cost. In sum, the process is a valuable tool to guide fracturing R&D and their chemical suppliers toward development of more environmentally acceptable products and systems.
The fruits of the process will be discussed in this endeavor, providing working examples of the chemical additive selection. Furthermore, the progress to more environmentally responsible fracturing processes through quantification of hazardous risk ‘removed’ from applications will be presented, i.e. the amount of hazardous material removed by replacement with more favorable alternatives.