鄂尔多斯盆地吴堡地区上三叠统延长组原油地球化学特征及油源对比
摘要: 鄂尔多斯盆地延长组油源一直存在争议，尤以长8~长10油藏的油源问题最为突出。通过吴堡地区延长组长6~长10原油的物理性质、族组成、生物标志化合物等特征，油-油、油-源对比等综合分析，探讨延长组原油的成因，明确各油层组石油来源，为该区的油气勘探与预测提供地质依据。结果显示，长6~长10原油族组分具有饱和烃含量最高，芳香烃次之，非烃和沥青质含量最低的特征。长6~长10均为成熟原油，显示出低等水生生物和高等植物混合成因，但长6原油与长7~长10原油族组成特征存在明显差异。长6原油为长7烃源岩早期烃类运移的结果，其成熟度最低，长7~长10原油为生烃高峰阶段石油运移结果，成熟度较高。长6和长7油藏的原油主要为长7底部张家滩页岩贡献，此外，长7中上部和长6地层中发育的有效烃源岩也有一定贡献。长8油藏原油为混合成因原油，主要为长7底部烃源岩向下运移结果，其次为长8内部烃源岩和长9顶部李家畔页岩之贡献。长9油藏原油主要为李家畔页岩向下倒灌形成，长10油藏可能主要为长92有效烃源岩向下运移成藏。热成熟度不同是导致远离主力烃源岩原油族组分之间差异性的主要原因。
Geochemical Characteristics of Crude Oil and Oil Source Correlation in Yanchang Formation(Upper Triassic) in Wubao Area, Ordos Basin
Abstract: The oil sources in the Yanchang Formation of the Ordos Basin has always been controversial, especially in the reservoir Chang8 to Chang10.According to the crude oil of Chang6 to Chang10 of Yanchang Formation in Wubao area, the article discusses the physical properties, the group composition, the biomarkers, and the oiloil and oilsource correlation in terms of their geneses and the origin of petroleum in respective reservoirs so as to provide the geological basis for the area's petroleum exploration and prediction. The result shows that the group composition of Chang6 to Chang10 is characterized by the highest content of the saturated hydrocarbon, which follows the aromatics, and non hydrocarbons are the lowest. Chang6 to Chang10 are all mature crude oil, revealing the hybrid origin of the lower hydrobionts and the higher plants, however, the crude oil in Chang6 is distinctively different from that in Chang7 to Chang10 in terms of its group composition. The crude oil in Chang6 is the early migration result of hydrocarbons in the source rock of Chang7 to Chang10, whose maturity is the lowest, while the crude oil in Chang7 to Chang10 is migration result of hydrocarbon generating peaks, whose maturity is superior. And the oil and source correlation demonstrates that Zhangjiatan shale, at the bottom of the Chang7, contribute to the oil pools in Chang6 and Chang7, in addition, the effective source rocks on the top and middle of Chang7 and Chang6 make difference. The oil pools in Chang8, mixed geneses crude oil, are mainly the down migration result of the lower source rocks in Chang7, secondly Chang8 and Lijiapan source rocks on the top of Chang9 do. The oil pools in Chang9 are formed by the downward flow of Lijiapan shale, but the petroleum in Chang10 is accumulated may by the downward migration of the effective source rocks of Chang92. The thermal maturity should be the most responsible for the differences between crude oil group compositions which are far away from the dominant source rocks.
鄂尔多斯盆地吴堡地区上三叠统延长组原油地球化学特征及油源对比[J]. 沉积学报, 2013, 31(2): 374-383.
| 引用本文: |
鄂尔多斯盆地吴堡地区上三叠统延长组原油地球化学特征及油源对比[J]. 沉积学报, 2013, 31(2): 374-383.
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Geochemical Characteristics of Crude Oil and Oil Source Correlation in Yanchang Formation(Upper Triassic) in Wubao Area, Ordos Basin[J]. Acta Sedimentologica Sinica, 2013, 31(2): 374-383.
| Citation: |
Geochemical Characteristics of Crude Oil and Oil Source Correlation in Yanchang Formation(Upper Triassic) in Wubao Area, Ordos Basin[J]. Acta Sedimentologica Sinica, 2013, 31(2): 374-383.
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