tullow discovers huge oil in the mercury-1 exploration well offshore sierra leone. by gerald businge on november 15, 2010 tullow oil expoloration , tullow oil in africa , tullow oil sierra leone news & events , public platform. anadarko petroleum corporation (nyse: apc) today announced the mercury-1 exploration well offshore sierra leone encountered approximately 135 net feet of oil pay in two cretaceous-age fan systems. mercury is the company’s second deepwater test in the sierra leone-liberian basin and was drilled to a total depth of approximately 15,950 feet in about 5,250 feet of […].