This project further investigated the relationship between the oils' chemical composition and viscosity on dispersant effectiveness. The viscosity, saturates, aromatics, resins, and asphaltene content were determined for the oils tested. Approximately 14 oils were tested against two dispersants at two temperatures. The baffled flask method was used, along with the LISST and acoustics, to determine dispersant effectiveness.
Chemical Treating Agents
The objective of this project is to conduct an oil spill response viability analysis for the U.S. Outer Continental Shelf (OCS) Gulf of Mexico (GOM). This analysis will quantify the frequency and duration that a specific oil spill response strategy may not be feasible or ‘unduly’ impacted such that response effectiveness is judged to be degraded due to metocean conditions. Conditions to be considered in the analysis include wind, sea state, salinity, and visibility using available hindcast environmental data.
Comparative Testing of Corexit EC9500A, Finasol OSR 52, Accell Clean DWD, Marine D-Blue Clean, and ZI 400 at Ohmsett
The Bureau of Safety and Environmental Enforcement (BSEE) is conducting comparative dispersant testing in warm water at the Ohmsett Facility test basin. This work builds off of the cold water test conducted in 2014 (Project OSRR 1016). Five dispersants were selected from the Environmental Protection Agency's (EPA) National Contingency Plan (NCP) Product Schedule and were tested on a Gulf of Mexico crude at Ohmsett. They include Corexit® EC9500A, Finasol® OSR 52, Accell® Clean DWD, Marine D-Blue Clean, and ZI 400.
This study will measure the influence of oil characteristics and temperature on herder efficacy at the lab scale. ARA will systematically test the function of chemical herders across several crude oils. Both commercially available herders and emerging new formulations will be utilized. The herders will be tested on crude oils with varying properties. This information will support operational decisions to use herders during a response, and enhance the Bureau of Safety and Environmental Enforcement's ability to evaluate the feasibility and likelihood of successful use of chemical herders.
Combining Mineral Fines with Chemical Dispersants to Disperse Oil in Low Temperature and Low Mixing Energy Environments
The objective of this research is to assess the feasibility of a cold water and Arctic marine oil spill countermeasure strategy based on the stimulation of OMA formation in the presence of a chemical dispersant. Evaluations will be conducted on both laboratory and wave tank systems under controlled conditions to evaluate the potential effectiveness of treatment of oil spills from shipboard and rig operations.
Project will determine the limiting viscosity for the effectiveness of chemical dispersants applied to viscous U.S. Outer Continental Shelf (OCS) crude oils from the Gulf of Mexico and Pacific OCS. Conduct physical and chemical analysis of the acquired crude oils to categorize them based on properties.Conduct small scale wave tank dispersant effectiveness on crude oil samples. These experiments will be conducted using Corexit 9500 applied at the standard 1:15 dispersant to oil ratio (DOR). Identify six oils from small-scale testing and test them at Ohmsett in moderate breaking waves.
This project developed a Computational Fluid Dynamics (CFD) model of the forces acting on dispersant as it is sprayed from four commonly used aircraft models.
OSRR-1067-Characterizing Dispersant Effectiveness of Crude Oil at High Salinities: Implications for Subsea Spill Preparedness
The objective of the proposed research is to evaluate the influence of salinity on dispersant effectiveness for select oils and dispersants, from 10-125 psu salinity, using the baffled flask test which provides a broad range of sufficient mixing energy including those observed in field conditions. Additionally, this project will characterize dispersant effectiveness during wave/flume tank simulations of high-velocity subsea releases of oil injected with dispersant at high salinities and subsequent mixing of plume to capture relative changes in dispersant effectiveness.
Analysis of How Environmental Conditions Affect Dispersant Performance During Deep Ocean Applications
This project determined how subsea conditions of pressure, pressure drop, temperature, solution gas-oil ratio (GOR), dispersant-to-oil ratio (DOR), sediment, and hydrates affect the effectiveness of dispersants. Specifically, the project investigated:
-The impact ambient water pressure and the pressure drop expected at a blowout have on oil-dispersant mixes;
-The effect temperature differentials between oil, dispersant, and surrounding seawater have on oil-dispersant mixes;
-The effects sediments have on oil-dispersant mixes; and
OSRR-1059-Characterizing Wave-Induced Mixing Energy in Ohmsett Wave Basin for Dispersant Effectiveness Testing
The objective of this project is to quantify the mixing energy in Ohmsett's test tank during wave conditions. Mixing energy is a key parameter in dispersant effectiveness tests and is quantified in small and intermediate scale tests by such methods as the EPA baffled flask test. To collect data that will help correlate dispersant effectiveness tests conducted at small scale with those conducted at Ohmsett, NRL will tow a MicroRider turbulence sampling package in Ohmsett's test tank at different depths and wave conditions.