The principal asset of OPTI consists of a 35% working interest in the Long Lake and three other oil sands project areas located in the Athabasca region of northeastern Alberta. Long Lake project includes steam assisted gravity drainage (SAGD) Operation and an upgrader.

Nexen holds the remaining 65% and is the sole operator. The Long Lake SAGD Operation is expected to have through-put rates of approximately 72,000 barrels per day of bitumen at full production. It is anticipated that the Long Lake Upgrader will ultimately produce approximately 58,500 barrels per day of products, primarily Premium Sweet Crude (PSC).

As disclosed in OPTI’s disclosure documents filed with securities regulatory authorities in Canada, OPTI’s working interest share, before royalties, of raw bitumen reserves and resources on its oil sands leases is estimated to be 195 million barrels of proved reserves, 534 million barrels of probable reserves, 1,100 million barrels of contingent resources and 335 million barrels of prospective resources. These reserves and resources are estimated to be sufficient to support approximately 430,000 barrels per day (150,000 barrels per day net to OPTI) of bitumen production.

CNOOC is China’s largest producer of offshore crude oil and natural gas and one of the largest independent oil and gas exploration and production companies in the world. The Group mainly engages in exploration, development, production and sales of oil and natural gas. The Group has four major producing areas in offshore China: Bohai Bay, Western South China Sea, Eastern South China Sea and East China Sea. Overseas, the Group has oil and gas assets in Indonesia, Australia, Nigeria, Argentina, the US and some other countries.

As of 31 December 2010, the Group owned net proved reserves of approximately 2.99 billion BOE, and its average daily net production was 900,702 BOE.

Due to a change in control of OPTI as a result of the transaction, OPTI will be required to offer to repay the holders of its outstanding First Lien Notes (US$825 million in principal amount) pursuant to the indentures governing the First Lien Notes. The transaction will be effected by way of a plan of arrangement through concurrent proceedings under the Companies’ Creditors Arrangement Act (Canada) and the Canada Business Corporations Act.

The proposed transaction must be approved by the Second Lien Noteholders at a special meeting that is expected to be held in September, 2011. Noteholders representing approximately 55.2% of the principal amount of the Second Lien Notes have executed support agreements pursuant to which, among other things, they have agreed to vote in favor of the transaction.

The proposed transaction is also subject to certain terms and conditions, including, among other things, applicable government and regulatory approvals by the relevant authorities in Canada and the People’s Republic of China, and Canadian court approval. The transaction is expected to be completed in the fourth quarter of 2011. Upon completion of the transaction, OPTI will become an indirect wholly-owned subsidiary of CNOOC, and all of the Second Lien Notes will be transferred or assigned, directly or indirectly, to a subsidiary of the Company. All existing options, warrants and other rights to purchase OPTI shares will be cancelled.

CNOOC’s financial advisors are BMO Capital Markets and CIBC World Markets; legal advisor is Gowling Lafleur Henderson LLP.