M4ShaleGas has provided ca. 90 technical reports which are available on the project’s website and also via the European Commission’s CORDIS information service. In the project, risks and impacts of shale gas exploration and exploitation. The main risks, incidents and impacts for operations in the U.S.A. and Canada have been found to be: (1) Risks associated with reduced general safety mainly related to incidents related to transportation (traffic-related accidents) and well site activities (preparation of fracturing fluids), (2) risks associated with reduced air quality and global climate footprint mainly related to incidents related to emissions of potentially hazardous substances (VOC, NOx, SOx, PM, HAP, O3) and greenhouse gasses (CH4, CO2), (3) risks associated with well leakage mainly determined by incidents mainly related to drilling (borehole damage and leakage) and completions (well barrier or integrity failure) of wells, (4) risks associated with surface spills mainly related to spills and leaks of potentially hazardous substances (fracturing chemicals or fluids) or flowback and produced water, (5) risks associated with landscape disturbance mainly related to well site construction in cultivated and industrialized land, or in pristine natural habitats, (6) risks associated with structural damage due to induced seismicity mainly related to fluid injection for hydraulic fracturing or subsurface fluid disposal, (7) risks associated with reduced water availability and quality mainly related to water use and local conditions (aridity of area), (8) risks associated with loss of geological containment (leakage along hydraulic fractures).
Apart from these technical risks, risks associated with absence of a social license to operate have found to depend on complex relations between public perceptions and shale gas operations, and more systematic studies are warranted. Although direct application to Europe is not meaningful due to a lack of data and different settings, the analysis can prioritize regulations and risk mitigation measures.
Risks assessment was based on a framework that consists of three components: (1) a Markov Chain-type approach to describe the transition from a properly operating shale gas well (base state) to absorbing states where incidents have caused contamination of shallow aquifers or problematic seismicity, (2) a bow-tie approach to describe incidents that lead to a transition between states in terms of its causes and effects with associated preventive and control measures, and (3) a risk assessment matrix that classifies risks according to their probability of incident occurrence and effects. Probabilities of incidents occurrence and effects of incidents are based on the review of data from shale gas operations in the U.S.A. and Canada.