Buhari orders revoked oil leases returned to China-owned Addax The Nigerian government, through the DPR, had revoked the four OMLs, citing the company's inability to comply with targets. Department of Petroleum Resources to restore four oil mining licences revoked from Addax Petroleum. The was disclosed in a statement by the president’s aide, Garba Shehu, on Friday. Addax, owned by the Chinese state-run Sinopec, has a production sharing contract with the Nigerian National Petroleum Cooperation. The Nigerian government, through the DPR, had revoked the four OMLs, citing the company’s inability to comply with targets. Two weeks ago, a committee set by Mr Buhari to investigate Addax submitted a report, accusing the petroleum company of “economic waste.”