The Law of Petroleum Accumulation in Chang 9 and Chang 8 Formation in Xizichuan Oil field

The main reservoirs in the Mesozoic of Xizichuan oilfield are distributed in Chang 6,Chang 2,Chang 4+5 of Triassic Yanchang formation,especially enrichment in Chang 6 and Chang 2.With the development of exploration,Chang 9,Chang 8 reservoirs continue to be discovered,which is subtle,small sized and harder to discover.The present study shows that they are cont rolled by multiple factors.The distribution of reservoirs is mainly cont rolled by sedimentary faces,nose-shaped uplift is important for oil enrichment.