鄂尔多斯盆地西南缘长8段油源多元精细对比

Oil-source rock fine multiple correlation of Chang 8 Section in southwest of Ordos Basin

白青林 杨少春 马芸 来又春 荆亚云1

中国石油大学（华东）地球科学与技术学院，山东 青岛 266580 中海石油（中国）有限公司天津分公司，天津 300459

School of Geosciences, China University of Petroleum, Qingdao 266580, China Tianjin Branch of CNOOC Ltd., Tianjin 300459, China

彭阳-崇信地区位于鄂尔多斯盆地西南缘，由于与长7段生烃中心相距较远，不同的研究人员对其长8段油源有着不同的认识。以原油与烃源岩的饱和烃色谱、色谱￣质谱特征为依据，利用聚类分析等方法，综合多项生物标志化合物参数，多角度探讨了西南缘长8段的油源。研究结果表明：区内与生烃中心的长7段烃源岩分别属于2个不同的类型，北部彭阳地区的长8段原油由生烃中心腐泥型的长7段烃源岩生成，成熟度较高，南部平凉地区长8段原油由区内腐殖型的长7段烃源岩生成，成熟度较低；区内长8段原油分布的差异性主要受控于烃源岩的有机碳质量分数，低有机碳质量分数的平凉地区烃源岩生排烃量只能满足本地成藏，彭阳地区的长7段泥岩缺乏相应的生排烃能力，只能由生烃中心的原油异地充注成藏。

Located in the southwest of Ordos Basin, Pengyang-Chongxin region is far away from hydrocarbon generating center of source rocks in Chang 7 Section. There are different views on the oil sources of Chang 8 Section. Based on the results of GC and GC-MS analysis on crude oil with source rock′s saturated hydrocarbons, the distribution characteristics of a series of biomarkers have been depicted. Combining these biochemical parameters, the oil sources of Chang 8 Section are discussed from multiple aspects by the way of manovacluster analysis and other methods of oil-source rock correlation. The study results show that the Chang 7 source rocks in this two areas belong to two types in the area of hydrocarbon generating center and Pingliang area. The maturity of Chang 8 crude oil accumulated in Pengyang area is higher than Pingliang area, and it is generated by Chang 7 source rock in the area of hydrocarbon generation center. Whereas Chang 8 crude oil in Pingliang area was generated by Chang 7 source rock which is located in the same area with the oil. The distribution differences of Chang 8 crude oil among different areas are mainly controlled by the distribution difference of TOC. For the reason of lower TOC, the quantity of hydrocarbon generation and expulsion by Chang 7 source rock in Pingliang area can only afford to meet native accumulation in Chang 8 Section. The Chang 7 source rock of Pengyang area lacks the capability of hydrocarbon generation and expulsion so that the trap of Chang 8 Section in this area cannot but be injected by crude oil generated in hydrocarbon generating center of Chang 7 source rock.

10.6056/dkyqt201806001