Development of a New Generation Modelling System for the Prediction of the Behaviour and Impact of Offshore Discharges to the Marine Environment

Abstract

Abstract This paper describes a programme of modelling, experiments, and field studies aimed at developing a management and planning tool capable of predicting the behaviour, transport, fate and impact of a range of contaminants discharged from offshore platforms. The modelling system (PROTEUS), includes models of the three-dimensional dispersion of effluent and solid waste discharges under conditions of time-varying current flow, meteorology, and variable bathymetry. These models have been calibrated with a range of experimental and field studies including laboratory simulation of effluent plume mixing, offshore sampling and laboratory experiments to determine the behaviour of discharged cuttings, and field studies of the dispersion of produced water plumes. PROTEUS also incorporates models of chemical behaviour that have been based on a programme of laboratory studies of sediment-water partitioning using 14C-labelled petrogenic and production chemicals. Ecotoxicological risk assessment methods have been developed for application to all discharge types. PEC:NEC methods have been implemented based on the rigorous dynamic PEC values predicted by the physicochemical models. Biokinetic models have also been implemented that simulate the uptake of chemical into target biota which is then assessed by computing critical body residue risk ratios, or by utilising body burden – mortality regressions derived from laboratory toxicity tests. The modelling system has been designed within a recently developed software framework that provides highly user orientated GIS-based model set-up, execution, and visualisation tools. Data outputs have been tailored through user consultation to directly support operational needs.