An integrated chemical management methodology for hydraulic fracturing: A fuzzy-based indexing approach

A fuzzy-based indexing approach was developed for the management of hydraulic fracturing chemical additives. The environmental and human health hazards of an additive are converted to hazard indices using an indexing system. To account for uncertainties, a fuzzy-based approach is adopted based on fuzzy inference and fuzzy clustering analysis to assess the risk potential of different additives for informed chemical management decision making. The assessment of the randomly selected additives showed that this fuzzy-based indexing approach gave different chemical hazard assessment results for about 30% of the assessed additives. This shows that accounting for uncertainties using this methodology can lead to better informed chemical management decision making. The hazard assessment results also indicate that based on current indexing methodology more than half of the additives permitted for use in hydraulic fracturing operations are considered moderate environmental and human health hazards. However, based on the new fuzzy-based approach the majority (80%) of the additives were identified as low and very low risk potential due to their low use frequencies.