Water, Wastewater & Stormwater


393607 - Monte Carlo Mixing Zone Study of Sediment Transport in an Offshore Environment

Tuesday, June 5
4:00 PM - 5:30 PM
Location: Greenway EF
Co-Authors: Adi Ramachandran, Portland, OR – MixZon Inc; Frank Opila, Portland, OR – MixZon Inc

Development of offshore oil and gas wells often includes the discharge of drilling muds and cuttings into the ocean. Modeling the resulting sediment plume trajectory and sediment deposition on the ocean bottom is useful for evaluating environmental impacts resulting from offshore drilling. A case study is presented based on a drilling muds and cuttings discharge from an offshore oil platform. CORMIX mixing zone modeling software was used to model plume sediment transport, suspended solids concentrations, and bottom deposition. CORMIX can simulate sediments as either dredge sediments or drilling muds and cuttings. Outfall configurations can be single port, multiport, surface or above surface discharges. For drilling muds and cuttings, CORMIX supports modeling of up to 10 custom particle size classes, including particle fall velocities. Data for the case study were obtained from a field study conducted in the Gulf of Guinea. Drilling muds and cuttings were discharged on the surface from an offshore platform in about 46 m of water. Availability of ambient and discharge data from the project site were limited. In the absence of detailed ambient current speed, direction, and depth data for the site, a statistically-based, Monte Carlo time series was developed. Nine sediment particle sizes and their corresponding fall velocities were specified. The CORMIX model simulated discharges over a period of several days. Multiple CORMIX simulations for different discharge durations and ambient time series data, were input to the CorPlot post-processing tool to simulate sediment transport and bottom deposition. Graphical visualization of the sediment deposition is presented.

Robert L. Doneker, PhD, PE

Mixzon Inc

Dr. Robert L. Doneker, PhD., P.E. is the President/CEO of MixZon Inc.

Dr. Doneker has over 30 years of experience in environmental engineering, teaching, and professional practice. Dr. Doneker has authored over a dozen publications on mixing zone analysis and key USEPA mixing zone guidance documents. Dr. Doneker is the primary developer of the CORMIX software for mixing zone analysis.

In addition, Dr. Doneker has instructed mixing zone modeling workshops that several USEPA regulators and DEQ permit writers from several states have attended.

MixZon Inc. specializes in technology development for Regulatory Mixing Zone analysis, outfall design and modeling. MixZon was established by Dr. Doneker in 2002, and has over 8000 clients worldwide who use its mixing zone modeling software – CORMIX. MixZon offers mixing zone modeling, licensing, consulting, technical support, training and field monitoring services. MixZon Inc. is a small business located in Portland, Oregon USA.

CORMIX is a USEPA-supported mixing zone model and decision support system for environmental impact assessment of regulatory mixing zones resulting from continuous point source discharges. The system emphasizes the role of boundary interaction to predict steady-state mixing behavior and plume geometry. The CORMIX methodology contains systems to model single-port, multiport diffuser discharges and surface discharge sources. Effluents considered may be conservative, non-conservative, heated, brine discharges or contain suspended sediments. Advanced information systems provide documented water quality modeling, NPDES regulatory decision support, visualization of regulatory mixing zones, and tools for outfall specification, design and optimization.

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393607 - Monte Carlo Mixing Zone Study of Sediment Transport in an Offshore Environment

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