Energy shares are mixed in mid-session trading as the broader market sinks, while crude futures are surging above $90 a barrel. In mid-day news, violent clashes between Libyan police and protesters has spread to Tripoli. The nation's autocratic leader, Moammar Gadhafi, appeared to lose control of some eastern parts of the country to anti-regime forces, The Wall Street Journal reported. Chesapeake Energy (CHK) said late Monday it will sell its interests in approximately 487,000 net acres of leasehold and producing natural gas properties in the Fayetteville Shale play in central Arkansas to a unit of BHP Billiton (BHP) for $4.75 billion in cash before certain deductions and standard closing adjustments.