CNPC's O8 oil and gas discoveries to trail 07

BEIJING, Dec 1 (Reuters) - China's top oil firm, China National Petroleum Corp (CNPC), said its proven oil reserves discovered in 2008 will rank as its third highest in history.

Newly discovered gas deposits would surpass 400 billion cubic metres for the fourth time in the company's history, CNPC said in an announcement on its Web site (www.cnpc.com.cn).

The parent of PetroChina (601857.SS)(0857.HK)(PTR.N) did not provide figures for the newly added proven oil reserves, which need to be certified by the Ministry of Land and Resources.

However, the discoveries would trail those of 2007 when CNPC announced record additions of proven geological oil reserves of 832 million tonnes and gas deposits of 445.4 billion cubic metres after a major find in the Jidong Nanpu oilfield in the Bohai Bay.

Chinese government and industry estimates of oil and gas reserves often differ significantly from those in the west, which are governed by strict definitions that make clear how much of a field's oil is expected to be produced over its life time.

CNPC, which produced nearly 60 percent of China's oil and nearly 80 percent of gas in 2007, has been counting on revving up natural gas explorations in recent years to partly offset limited crude oil potentials.

In 2007, its oil production increased just 0.9 percent from a year earlier while gas output soared 22.7 percent.

A majority of CNPC businesses are run by PetroChina.

(Reporting by Jim Bai; Editing by Anne Marie Roantree)