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July 21, 2010
New GoM spill containment system: the technology
Chevron, ConocoPhillips, ExxonMobil and Shell are accelerating the engineering, construction and deployment of equipment designed to improve capabilities to contain a potential future underwater blowout in the Gulf of Mexico.
This system offers key advantages to the current response equipment in that it will be pre-engineered, constructed, tested and ready for rapid deployment in the deepwater Gulf of Mexico. Its primary objective is to fully contain the oil with no flow to the sea. The system will be flexible and adaptable. It will be responsive to a wide range of potential scenarios, deepwater depths up to 10,000 feet, weather conditions and flow rates exceeding the size and scope of the current spill. Once constructed, the system components will be fully tested to ensure functionality and will be maintained in a state of continuous operational readiness. In the event of a future incident, mobilization to the field will start within days and the system will be fully operational within weeks.
A newly designed and fabricated subsea containment assembly will create a permanent connection and seal to prevent oil from escaping into the water.
The assembly will be equipped with a suite of adapters and connectors to interact with various interface points such as the wellhead, blowout preventer stack, lower marine riser package and casing strings, including any well design and equipment used by the various operators in the Gulf of Mexico.
The assembly will be designed to prevent hydrate formation and blockage.
Capture caisson assemblies will also be built for use if required to enclose a damaged connector or leak outside the well casing. Once installed, these assemblies will create a seal with the seabed to prevent seawater from entering the system.
The oil would be captured by the subsea containment assembly and flow through flexible pipe to a riser assembly. Riser assemblies are made of a seabed foundation, vertical pipe, buoyancy tanks and a flexible pipe specifically configured to connect to the capture vessels.
The subsea system will be supplied with the necessary hydraulic / electric controls and chemical injection (such as hydrate inhibitors) through an umbilical.
A manifold will distribute the oil from the subsea containment assembly to multiple riser assemblies if more than one capture vessel is necessary.
Riser assemblies and umbilical will be designed to quickly disconnect from capture vessels so that all subsea equipment stays in place in the event of a hurricane. An additional system component will be available to inject dispersant into the subsea containment assembly if required.
The system includes capture vessels that can process, store and offload the oil to shuttle tankers to take the oil to shore for further processing.
Capture vessels may include modified tankers, existing drill ships and extended well-test vessels.
The plan includes the construction of modular process equipment that will be installed on the capture vessels. The modular process equipment will connect to the riser assembly, separate oil from gas, flare the gas and safely store and offload oil to shuttle tankers. The shuttle tankers will be U.S.-flagged and Jones Act compliant.
During hurricanes, the capture vessels would disconnect and move away from the storm for the safety of the operating personnel. Once the hurricane passes, the vessels would return and be operational within days.
The sponsor companies will immediately start design, procurement and construction of equipment for this system. Initial investment to construct new subsea and modular process equipment is expected to be approximately $1 billion.
ExxonMobil has been designated by the founding sponsors to lead the engineering, procurement and construction of the system components.
Existing equipment will be secured and available within six months with the new system targeted for completion within 18 months.
The sponsors will form a new non-profit organization, the Marine Well Containment Company (MWC) to operate and maintain the system. They say that other Gulf of Mexico operators are encouraged to participate in this new organization.