Mesozoic hydrocarbon accumulation model in the Northern South China sea

Abstract The ChaoShan Depression is the largest Mesozoic depression covering an area of 3.7 x 10 4 km 2 where relict strata are up to 5000 m thick. It has experienced disruption since late Mesozoic. In early survey, oil-gas migration condition and reservoiring mechanism poorly expounded from Meso-Cenozoic tectonic superposition due poor seismic imaging deep layers. New surveys using long streamers quasi three-dimensional layouts improved obviously images formations, enabling analysis tectono-stratigraphic features petroleum geology. Correlating regional stratigraphic facies characteristics well LF35-1-1 onshore outcrops, two sets source layer tested with high organic carbon content interpreted within upper Triassic mid-Jurassic semi-closed gulf sequences which become thicker toward east side Dongsha Island. Three potential reservoir beds also interpreted, a basin-floor fan sandstone Triassic-Jurassic boundary, limestone atop mid Jurassic, sandy in Upper Jurassic. Over low bulge Depression, big anticline found bounded by faults played as passage for hydrocarbon Likely, one set fault act reverse barrier block escape, thus form fault-bounded trap, favorable future exploration.