Zhujiangkou Basin is a major petroliferous basin which covers an area of 150

000kim

2

on the northern continental shelf of the South China Sea.Its generation

development and formation are mainly due to Meso-Cenozoic uplifting and subsiding movements of the crust.The sediments of Cenozoic there are as thick as 6

000m with 3 large depressions in this basin.On the basis of data collected from seven wells sited on the northern margin of the basin and in the western part of Zhu-1 depression

the stratigraphic sequence have been reconstructed from top to bottem:Quaternary system

the Wanshan Formation of Pliocene

the Yuehai

Hanjiang and Zhujiangkou Formations of Miocene

and the Zhuhai Formation of Oligocene.Among them

sediments from Quaternary to Hanjiang Formations are of neritic to littoral facies

while those from Zhujiang to Zhuhai Formations are of littoral to lagoonal facies.Commercial oil flow had gushed up from the Tertiary system which tested in some wells in recent years.These formations

especially the Hanjiang

Zhu-jiang and Zhuhai Formations

are generally believed to be very promising with good oil generation and entrapping conditions.