1 Department of Building, Civil, and Environmental Engineering, Concordia University, 1455 de Maisonneuve Blvd. W, Montreal, Quebec, Canada, H3G 1M8. Electronic address: zhichen@bcee.concordia.ca.
2 Department of Building, Civil, and Environmental Engineering, Concordia University, 1455 de Maisonneuve Blvd. W, Montreal, Quebec, Canada, H3G 1M8.
3 Ecosystem Science, Fisheries and Oceans Canada, 200 Kent Street, Ottawa, Ontario, Canada, K1C 0E6.
4 Ocean Modelling and Monitoring Section, Ocean and Ecosystem Sciences Division, Maritimes Region, Fisheries and Oceans Canada, Bedford Institute of Oceanography, 1 Challenger Drive, Dartmouth, Nova Scotia, Canada, B2Y 4A2.

Offshore oil exploration and production in deepwater are associated with environmental risks to marine ecosystems. This research introduces DWOSM (Deep Water Oil Spill Model), a three-dimensional Lagrangian model, which is developed to simulate the transport and fate of oil spills resulting from subsea blowouts. DWOSM comprises three interconnected modules: DWOSM-DSD, which predicts the oil droplet size distribution from a blowout release; DWOSM-NearField, simulating plume dynamics and tracking oil droplets within the plume region; and DWOSM-FarField, modeling the evolution of dispersed oil beyond the near-field. Compared to other oil spill models, this integrated approach improves the transition between near and far fields using a near-field particle tracking algorithm. It also employs the thermodynamic models to enable the prediction of oil properties under varying deep water pressure and temperature. To gauge the reliability and efficacy of DWOSM, a hypothetical case situated within a North American context is employed for model testing. The DWOSM and its each module are juxtaposed with other established oil spill models. The outcomes indicate that DWOSM yields comparable results to these models by providing reasonable predictions of a deepwater blowout. The model's verification through case scenario testing and comparison underscores its potential as a decision tool for assessing and managing the potential environmental impacts of offshore petroleum activities.