东海盆地西湖凹陷平湖地区油气源对比及油气运移特征分析OACSTPCD

The characteristics of oil and gas sources and migration in Pinghu area of Xihu Sag,the East China Sea Basin were revealed based on the analysis of parameters such as biomarkers of crude oil and source rocks,carbon isotopes of crude oil,components of natural gas,carbon isotopes of natural gas,and physical properties and nitrogen containing compounds of crude oil.The results show that the distribution of C27,C28,and C29 steranes of the crude in the Huagang Formation of Block A in the Pinghu area of the Xihu Sag is mainly V-shaped(C27 ≈ C29＞C28)or L-shaped(C27＞C29＞C28);The C27,C28,and C29 of source rocks in Block A are mainly distributed in reverse L shape(C27＞C28＜C29),while those of the source rocks in the middle section of Pinghu Formation of Block D(H11 well)are mainly distributed in L shape,which is similar to the biomarkers of crude oil.The oil-source comparison results and the parameters related to nitrogen compounds show that the crude oil of the Huagang Formation in the Pinghu area has the characteristics of vertical and lateral short-distance migration(fault+sandstone).Gas-source comparison results and the δ13 C1 and dryness coefficient of the natural gas show that the natural gas in the Pinghu Formation of Block A and Block B in the Pinghu area mainly comes from the source rocks in Block A and B themselves and fault block D.