China Oilfield Services (COSL) is an oilfield service. It is a majority owned subsidiary of Chinese state owned company CNOOC Group. It also has a listed sister company in Hong Kong, CNOOC Limited. China Oilfield Services is seeking acquisition targets in Southeast Asia, the Middle East and Central Asia, to bolster its operating scale and technical competencies. But high oil prices and a speculative investment environment have made agreements difficult to come by, company secretary Chen Weidong told the South China Morning Post.