Reuters: Big oil companies including Exxon Mobil Corp and Royal Dutch Shell will spend $1 billion to develop a new oil spill containment system for the Gulf of Mexico, the companies said on Wednesday. The project, a response to BP Plc’s Gulf oil leak, will be engineered for water depths up to 10,000 feet — about twice the depth of BP’s crippled Macondo well. It will have initial capacity to contain 100,000 barrels (4.2 million gallons/15.9 million liters) of oil per day, the companies …