College of Earth Sciences;
Jilin University;
Changchun 130061;
China;
CNOOC China Ltd.;
Zhanjiang 524057;
China;
low; permeability; reservoir; pore; evolution; hydrocarbon; charging; 'sweet; spot'; distribution; Zhuhai; Formation; Oligocene; Wenchang; A; sag; northern; South; China; Sea;