It was at the beginning of this century that the assessing of China's Pe-troleum resource was initiated from the view point of geological science.Through exploration practise of more than 80 years

the understanding

evaluation and prediction of China's petroleum resource have experienced a long process

i.e.from geological inference to geological analogue

from qualitative to quantitativeevaluation.This historical process may be generally divided into four stages:1.The stage of geological inference started from the beginning of this cen-tury and ended in late 40's.In order to probe into the potential of China'spetroleum resource

a lot of bassically route survey had been carried out by afew pioneer geologists.After that

they foresightedly concluded that there areprospects of petroleum in China

and that petroleum can surely be generatedfrom continental deposites as it is in marine sediments.2.The stage of large scale petroleum prospecting and exploration were car-ried out mainly in Meso-Cenozoic continental basins and resulted in the dis-covery of the famous Karamay and Daqing giant oilfields.This important dis-covery enables our government anouncing stately to the world that the days ofdepending upon the import-oil had gone forever

and enables the policymakerto decide stratigically that China's petroleum industry should be undoutedly based on the crude oil and natural gas

industry of man-made oil would beexisted continuously only in a complementary scale.3.The stage of nationwide qualitative assessment from 60's to mid 70's.petroleum prospecting and exploration work had been taken place in every im-portant inland sedimental basins

and research tasks have been deepened eitherin petroleum geology or in geophysical and geochemical survey.Whereasexplorations of our leading geologists with the utilization of their own cre-atire theories

such as tectonic-controlled petroleum distribution

polycyclepetroleum generation and accumulation

oil origin and distribution regularities of oil and gas fields in terrestrial deposites

etc.all came to an end that China's petroleum resource is very plentiful

say

100 billion tons or more as itwas preliminaily estimated.4.Quantitative assessment stage from the year of 1978 to early 80's.The formation and distribution regularities of fault-block oilfields

subtle pools

paleoburied-hill oilfields

thrust-screened oilfields and the like are more tho-roughly sumarized

new concepts and methods are introduced from abroad.As a result

it is evaluated that the crude oil resource of China is about 60-66 billion tons and gas 20-25 trillion m

3

.The second round of large-scale petroleum prospecting and exploration having been carried throughout the country and its frutful initial achiements obtained in East China Sea

South China Sea

and Tarim Basin have proved that a brilliant perspective of petroleum industry in China is unfolded before our eyes.