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Clarkson University Professor Developing Computer Model For Prediction Of Deep Water Oil Spill Behavior
POTSDAM, N.Y. -- Clarkson University Civil and Environmental Engineering Professor Poojitha D. Yapa is leading a team of academic researchers in developing a computer model which predicts the behavior of oil and natural gas in the event of a spill from a deep water well.
Oil and natural gas production from deep water locations is on the rise. Many of the drilling sites are in the U.S. Gulf of Mexico, where deep water development is operationally defined as development in water depths greater than 1,000 feet. Deep water oil production has only recently become economically feasible; from only 6 percent of the production in the Gulf of Mexico in 1985, production increased to 36 percent in 1998. Although industries follow strict safety standards and there has never been a deep water spill, such drillings are not without risks.
A major spill would have safety, environmental and economic consequences. Being able to predict how the oil and natural gas released in a spill would behave is very important for a quick and effective clean-up response.
In a deep water spill, with the low water temperature and high pressure, the natural gas forms a slushy mixture of solidified gas and water known as a hydrate. The natural gas hydrates are buoyant and float towards the surface with the oil. As the natural gas hydrate nears the surface, the pressure is reduced, thus allowing it to return to gaseous form. The gas may dissolve in the water, thus rendering it harmless if well diluted, or it could come to the surface. If the gas reaches the surface in a large quantity, it poses a hazard due to its toxicity and flammability.
“If a large amount of gas came to the surface near a drilling platform where people were working, it could catch fire and cause an explosion,” said Dr. Yapa.
The computer model being developed by Dr. Yapa and others will predict how the oil and gas will behave. When the data about a spill is entered into the model, the program will predict whether gases will come to the surface, where the oil and gas will surface, and in what concentrations.
Because of the need to develop a better understanding of the impacts of deep water drilling, in 1998 the Minerals Management Service (MMS) of the United States Department of the Interior and several oil industries formed the Deep Spills Task Force (DSTF). The purpose of the DSTF is to cooperatively fund research addressing deep water development issues.
Using the competitive MMS research proposal solicitation process, the DSTF selected a proposal from a team headed by Yapa. Professor Yapa has extensive experience creating oil spill models, having developed ones for rivers near the Great Lakes, Tokyo Bay in Japan, the Ohio-Monongahela River system, and the St. Lawrence River. Yapa’s current project will develop a deepwater oil and gas plume dynamics model to simulate the transport of oil and natural gas released from deep water.
Clarkson’s modeling effort will be bolstered by experimental work from Dr. Stephen Masutani of the University of Hawaii and Dr. Eric Adams of the Massachusetts Institute of Technology (MIT). The joint project is expected to perform a series of laboratory experiments to support Dr. Yapa’s modeling effort.
Dr. Masutani will use both atmospheric and high-pressure test chambers to study oil droplet formation, size distribution and the effect of oil films on gas bubble behavior and natural gas hydrate formation in a simulated deepwater environment. Dr. Adams’ work deals with buoyant plume dynamics and the effects of cross-flow circulation on these dynamics.
Oil companies developed realistic scenarios for the researchers’ use. Daily flow rates, natural gas to oil ratios, jet pressures and deep-water oil characteristics were discussed by an industry subgroup. The resulting output were high-, medium- and low-flow rate scenarios that will allow for realistic and directly applicable simulations. Several oil companies provided oil samples for chemical analysis and experimental use. Such cooperation has led to a much-improved understanding of the chemical and physical characteristics of oils.
“This is a good case of industry, government and universities working towards a common goal and doing it well,” says Yapa. “And Clarkson is in the center of it.”
In addition, Chevron Corporation is leading a joint industry project known as “Project DeepSpill,” which in June conducted a controlled, experimental release of oil and natural gas in deep water off the coast of Norway. Dr. Yapa and his team were involved in the design of the experiment. The data gathered from the controlled release will be used to calibrate and assess the deepwater model in development at Clarkson University. Another model for deep spills was developed recently by Sintef, a Norwegian group that participated in Project DeepSpill. They will also use the experiment’s data to validate and adjust their numerical model.
Dr. Yapa expects Clarkson’s deep water spill model to be completed in early 2001.