Environmental Risk Assessment of Gas Wells Drilling Effluents: Integration of Environmental Failure Mode and Effects Analysis and Analytic Network Process Models

Environmental risk assessment, the process of qualitative analysis of potential hazards and coefficients of potential risks in the project, as well as the vulnerability of a peripheral environment need to be taken into account. Accordingly, the purpose of this study was to identify and investigate the potential hazards and  make practical suggestions in order to eliminate or reduce the environmental hazards related to gas wells drilling effluents and wastewater in southern cities.
This is an applied research using descriptive-analytical method. The required data were  categorized into two groups including: a review of written sources and a field study of one of the oil and gas wells based on the available components and variables. Data analysis was done using EFMEA (Environmental Failure Mode and Effects Analysis) and the components and variables were analyzed using  Analytic Network Process model (ANP). Analysis of variance and correlation coefficients were also used to investigate the relationship between the components. Finally, a strategy model was developed based on the studies 
conducted  to determine the effectiveness of corrective and control measures. Research findings based on EFMEA environmental risk assessment of oil and gas drilling effluents and wastewater showed that 83.4% of the risk scores, in this case, were placed at the medium risk level and 16.6% at the  low-risk level. The results of the network analysis model also showed that drilling effluents and wastewater caused by drilling wells of Oil and Gas had  the highest impact (0.124) on the degradation of vegetation and also on the destruction of the natural habitats in this region.
Accordingly, some strategies such as integration of EFMEA and ANP Models which were developed  to reduce the environmental crises in oil and gas drilling have been very useful and appropriate.