BreitBurn Energy Partners L.P. is an independent oil and gas master partnership focused on the acquisition, exploitation and development of oil and gas properties in the United States. Our objective is to manage our oil and gas producing properties for the purpose of generating cash flow and making distributions to our unitholders.
Our assets consist primarily of producing and non-producing crude oil and natural gas reserves located in the Los Angeles Basin in California, the Wind River and Big Horn Basins in central Wyoming, the Powder River Basin in eastern Wyoming, the Evanston and Green River Basins in southwestern Wyoming, the Sunniland Trend in Florida, the Permian Basin in Texas, the Antrim Shale in Michigan, and the New Albany Shale in Indiana and Kentucky. Our assets are characterized by stable, long-lived production and reserve life indexes averaging approximately 17 years. Our fields generally have long production histories, with some fields producing for over 100 years. We have high net revenue interests in our properties.
As of December 31, 2012, our total estimated proved reserves were 149.4 MMBoe, of which approximately 53 percent were crude oil and 47 percent were natural gas. Of our total estimated proved reserves as of December 31, 2012, 35 percent were located in Michigan, 26 percent in Wyoming, 17 percent in California, 14 percent in Texas, seven percent in Florida, with the remaining one percent in Indiana and Kentucky.