A discovery degree of petroleum resources is one of important factors that indicate petroleum exploration maturity.Because of the concepts of resources and reserve used in China and other countries are different

the terms of the discovery degrees used by them have also not same meaning.A misunderstanding might be made when the magnitude of the discovery degrees with different meanings are directly compared. According to the different meanings of resources and reserve concepts used at home and abroad

the discovery degrees of petroleum resources in place and recoverable resources have been introduced in this paper.The discovery degree of petroleum resources in place is the percentage of cumulative proven reserves in place with respect of total resources in place;the discovery degree of recoverable petroleum resources refers to the percentage of cumulative proven recoverable reserves with respect of total recoverable resources.By the end of 2000

the discovery degree of oil and gas resources in place in China is 20.5% and 7.7%

respectively

the discovery degree of recoverable oil and gas resources in China is 52.5% and 17.4% respectively;the discovery degree of recoverable oil and gas resources in the world is 57.3% and 50.3% respectively; the discovery degree of recoverable oil and gas resources in the U.S. is 56.4% and 57.6% respectively.Hence

the difference between the discovery degrees of recoverable oil resources in China and the world (or in the U.S.) is not too large

but the discovery degree of gas recoverable resources in China is much lower than that in the world and the U.S.