U.S. oil company Anadarko Petroleum said one of its wells, located in the Deepwater Tano Block offshore Ghana, encountered significant light oil accumulation.The Ntomme-2A appraisal well encountered about 128 net feet of light oil pay in excellent-quality sandstone reservoirs, the company said.Fluid samples from the well, which was drilled to a depth of about 12,810 feet, indicate oil of about 35 degrees API gravity, Anadarko said."We now estimate oil makes up the majority of the resource in place," the company said in a statement.Anadarko owns an 18 percent working interest in the Deepwater Tano block, which is operated by Britain's Tullow Oil plc, also with a 49.95 percent working interest.Other partners in the block include Kosmos Energy ltd and the state-owned Ghana National Petroleum Corp.