ACCUMULATION HISTORY OF MATURAL GAS SYSTEMS IN THE NORTHERN DEPTH OF SONGLIAO BASIN
YANG Feng ping 1, WANG Yu hua 2, YANG Bu zeng 2 (1.China University in Geosciences, Beijing; 2.Institute of Daqing Oilfield Exploration Limited Company)
The source rocks in the northern depth of Songliao Basin make a feature of Type Ⅲ organic matter and high maturation of wet/dry gas generation . According to burial, thermal and hydrocarbon generation modelling, as well as analysis of gas accumulating history by organic fluid inclusions, the paper indicates that the critical times of the Xujiaweizi and Yingshan fault depression gas systems are 72 Ma and 90 Ma, respectively, both being charged with gas in one phase. It suggests that the two gas systems are representatives that have undergone a long period of preservation since late Cretaceous.