Star Petroleum, owned 64% by Chevron at present, will raise about 3.1 billion baht from the sale of 345 million new shares at 9 baht each in the offering, it said in a filing with the nation's Securities & Exchange Commission on Monday. PTT Plc, the state-owned energy company, will offload its 36% stake, amounting to another 1.39 billion existing shares, at the same price to raise 12.5 billion baht, according to the statement.