دانلود رایگان مقاله ارزیابی خطر شکستگی هیدرولیکی مواد شیمیایی با استفاده از روش نمایه سازی

abstract

The rapid expansion of unconventional natural gas production has triggered considerable public concerns, particularly regarding environmental and human health (EHH) risks posed by various chemical additives used in hydraulic fracturing (HF) operations. There is a need to assess the potential EHH hazards of additives used in realworld HF operations. In this study, HF additive and fracturing fluid data was acquired, and EHH hazards were assessed using an indexing approach. The indexing system analyzed chemical toxicological data of different ingredients contained within additives and produced an aggregated EHH safety index for each additive, along with an indicator describing the completeness of the chemical toxicological data. The results show that commonly used additives are generally associated with medium-level EHH hazards. In each additive category, ingredients of high EHH concern were identified, and the high hazard designation was primarily attributed to ingredients' high aquatic toxicity and carcinogenic effects. Among all assessed additive categories, iron control agents were identified as the greatest EHH hazards. Lack of information, such as undisclosed ingredients and chemical toxicological data gaps, has resulted in different levels of assessment uncertainties. In particular, friction reducers show the highest data incompleteness with regards to EHH hazards. This study reveals the potential EHH hazards associated with chemicals used in current HF field operations and can provide decision makers with valuable information to facilitate sustainable and responsible unconventional gas production.

4. Conclusion

The EHH hazards of commonly used HF additives in BC were systematically assessed using an indexing system. The assessment results show that the commonly used additives are associated with medium to high levels of EHH hazard. Among the various additives, iron control agents show a high-level EHH hazard. Other commonly used additives, such as friction reducers, biocides, gelling agents, demulsifiers, clay control agents, and breakers, have an overall ASI b 6 (i.e., medium-level hazard), suggesting these additive categories are the primary areas for EHH hazard mitigation. Friction reducers show a very low level of data completeness during the assessment (i.e., an overall DAI b 25), and clay control agents, gelling agents, demulsifiers, anti-sludge agents also demonstrate a low level of data completeness (i.e., overall DAIs b 50), indicating more chemical information and toxicological data should be provided for these additive categories. More critically, a large percentage of additives containing ingredients of high aquatic toxicity and carcinogenic effects have been identified. Some of the most commonly used additives within their respective categories contain ingredients of combined high environmental health and human health hazards, resulting in high potential to pose serious threats to EHH if spills or contaminations occur. It was also found that environmental health hazards posed by HF additives are generally more critical than the human health hazards. The hazard assessment completed for five randomly selected fracturing fluids also indicates a medium-level EHH hazard based on the current use of fracturing fluids. Hydraulic fracturing operators should be encouraged to disclose more detailed chemical information to support a clearer understanding of the potential EHH hazards of chemical use in HF. Also, data gaps related to the toxicity of ingredients should be filled for more accurate and informed EHH hazard assessments. This study identifies the EHH hazards of representative additives used in Canadian unconventional gas production processes, and brings to light potential improvements that can contribute to promoting more sustainable and responsible unconventional energy production.