Geochemical Characteristics and Accumulation Process of Beihanzhuang Oilfield of Qintong Depression,Northern Jiangsu Basin
苏北盆地溱潼凹陷北汉庄油田油气成藏地球化学特征

Qintong depression are divided by three structure belts, the faulted belt, the deep sag belt and the slope belt, controlling the banded distribution of oil\|fields. Beihanzhuang oil\|field is in the exterior slope belt. According to the analysis of biomarker parameters and concentration in extracts of source rock and oil, combined with the routine geological and geochemical methods, the process of migration and accumulation of Beihanzhuang oil field is studied systematically. The results indicate that two types oil could be identified. The first type is Es1 and Ef3 member oil, which is derived from Ef2 member source rock of deep sag. The second type is Ef1 member oil which is derived from Ef1 member source rock of deep sag. Integrated with the analysis of pyrrolic nitrogen compounds and its parameters, Beihanzhuang Ef3,/Ef1 and Es1 member oil migrated from deep sag to Beihanzhuang structure belt apparently. Also, in accordance with of the generation and discharging history of hydrocarbon, the faulted sealing capacity and the formation stage of accumulation, Ef2 member source rock generated and expulsed hydrocarbon during the Dainan formation period and reached the generated hydrocarbon peak during the Eogene period, which is matched with the Ef3 member the formation stage of accumulation. After Sanduo movement, the vertical sealing capacity of Beihanzhuang faults was competent so that the Ef3, Ef1, Es1 member oil was generated from Ef2 and Ef1 source rock and migrated by Ef3 and Ef1 member sand body from deep sag to slope belt forming the lithologic\|structrual oil reservoirs dominantly.