CEO [CNOOC] CORRESP: September 26, 2012 Mr. H. Roger Schwall Ms.
[September 26, 2012 Mr. H. Roger Schwall Ms. Alexandra M. Ledbetter Mr. Norman von Holtzendorff Division of Corporation Finance 100 F Street, NE Mail Stop 7010 U.S.A. Re: CNOOC Limited Form 20-F for Fiscal Year Ended December 31, 2011 Filed April 20, 2012 Comment Letter Dated September 19, 2012 File No. 1-14966 Dear Mr. Schwall, Ms. Ledbetter and Mr. von]