BP took a writedown of $5 billion for the second quarter of 2012, for some U.S. refineries, a suspended Alaska oil project and shale gas resources. Of this $2.68 billion was for the U.S. refining business. And $1.50 billion was for the suspension of the Liberty oil project in Alaska because of higher costs. BP's clean replacement cost profit was $3.69 billion, a decline of 35% from the $5.71 billion the prior year. BP's writedown of shale gas assets was because of very low natural gas prices, a situation faced also by Shell and Exxon. Total oil and gas production declined by 7.4% to 2.275 million barrels of oil equivalent a day. The extended maintenance program and major repair and improvement work after the 2011 oil spill led to increased costs and lower production in the North Sea, Angola, and the Gulf of Mexico.