Spatio-temporal modelling of underwater noise related to an arctic exploration drilling program

One concern related to oil and gas industry activities in the arctic is the potential impact of anthropogenic noise on marine mammals. To gain understanding of the temporal evolution of the acoustic noise footprint from such activities, and to quantify the geographic extent at which sound levels remain within regulatory thresholds for marine mammal injury and behavioral disturbance, this work presents a comprehensive monitoring and modeling study of anthropogenic noise resulting from an exploration drilling project in the northeastern Chukchi Sea, conducted from July to October, 2015. Measured acoustic source levels of multiple vessels and drilling equipment were used to generate time-dependent wide-area noise fields. Model validation was carried out by comparing simulated results with high-resolution acoustic data acquired at multiple stations in the area. The study shows that noise radiating from up to 19 supporting vessels is usually dominant, but noise from certain drilling-related activities occasionally rises above vessel noise within a radius of 8 km from drillsites. Modeled scenarios also show that by constraining vessel positions to within a few kilometers of the drilling location, simultaneous construction of two oil well top holes results in minor increment of the aggregate acoustic footprint’s extent relative to single-well drilling.