Blueknight Energy Partners (formerly SemGroup Energy Partners) provides gathering, transporting, terminalling, and storage of crude oil in Oklahoma, Kansas, and Texas. It operates two pipeline systems (1,285 miles of pipeline) delivering crude oil to refineries, and provides storage services with a capacity of about 8.1 million barrels. It also provides asphalt services. Blueknight Energy Partners has about 7.4 million barrels of asphalt and residual fuel storage in 45 terminals located in 22 states. Blueknight Energy Partners' top customer is Netherlands-based natural resources group Vitol (54% of total revenues in 2010). Vitol and investment firm Charlesbank Capital Partners indirectly own the company.