Thesis (S.M.)--Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2013.Cataloged from PDF version of thesis.Includes bibliographical references (pages 153-155).BP needed almost 3 months to cap the Deepwater Horizon spill; improved response techniques are needed for the future. This work presents the design and deployment plan for a new type of containment system that captures the vast majority of hydrocarbons exiting the wellhead. The structure is lightweight, flexible and modular, using a passively induced chimney affect as its working principle. It is modular to create one design that fits any number and size of wells. Modularity comes from 100m sections of thin Kevlar fabric, forming a cylinder that starts several meters above the seabed and ends several meters below the sea surface. The system is stored onshore mostly assembled until needed. The 3m-diameter shroud induces a flow that dilutes the gas to avoid hydrate formation. Yet the velocity is sufficiently small for gas to dissolve, reducing surface gas concentrations below workers' safety thresholds. The chimney effect causes a pressure differential over the material; reinforcement ribs are required to keep the system from collapsing inward. At the shroud top, the jet enters a containment pen, which is loosely attached to the shroud allowing it to ride the waves in heave, but constraining roll, pitch and yaw. The pen diameter allows oil to separate from the water; a skimmer weir in the pen collects almost pure oil and pumps it to a tanker. An air can at the shroud top provides pre-tension that restrains lateral deflections due to a uniform current, and helps reduce the collapse due to the pressure differential. The deflection and collapse are calculated for a uniform current using catenary equations. The results are used to verify the applicability of OrcaFlex, software commonly used by the offshore industry, which is then used to confirm the systems ability to satisfy design requirements under realistic conditions (a sea spectrum and non-uniform current). The 'one design fits all' objective is tested by initially designing the system for a moderate size reference well, and then scaling it up (with minor modifications) to fit the Macondo well. The results confirm that one design of the system can contain spills of moderate size in addition to those similar to the Deepwater Horizon.by Natasha Maas.S.M
