松辽盆地齐家-古龙凹陷扶余油层油气成藏区带定量预测与评价

Quantitative prediction and evaluation of hydrocarbon accumulation plays in Fuyu reservoir in Qijia‑Gulong Sag in Songliao Basin

齐家-古龙凹陷扶余油层是松辽盆地后备接替储量的重要勘探目标之一,但其已有的油气成藏认识成果过于宏观,不能满足现阶段的精细勘探需求。为进一步优选勘探目标,以功能要素组合理论为依据,结合研究区的断层-岩性油气藏类型,综合分析断块类、岩性类油气藏的各项主控因素,选取烃源灶、沉积相、势能、区域盖层及断裂带5个因素作为成藏要素,并分别进行定量表征,计算综合控藏概率。结果表明:92%的油气藏分布在距离排烃中心小于30 km的范围内;50%以上的油气藏分布在水下分流河道;油气藏均分布在势指数小于0.8的区域内;40%的油气藏分布在厚度为70~80 m的区域盖层之下;油气藏均分布在距断裂小于1.6 km的区域内;齐家-古龙凹陷扶余油层存在3个Ⅰ类成藏区。统计表明,85%以上的已发现断层-岩性油气藏分布在Ⅰ类成藏区。研究成果可为齐家-古龙凹陷的深化勘探提供指导。

Fuyu reservoir in Qijia-Gulong sag is one of important exploration targets for reserves replacement in Songliao Basin.The existing understandings are too macroscopic and cannot meet the needs of fine exploration at current stage.For further optimizing exploration targets,on the basis of functional elements combination theory and combined with the type of fault-lithologic reservoirs in studied area,the main controlling factors of fault block reservoirs and lithologic reservoirs are integrated and 5 elements including source kitchen,sedimentary facies,potential energy,regional seal and fault zone are selected as accumulation elements to perform quantitative characterization respectively and calculate comprehensive reservoir control probability.The results show that 92%of reservoirs are distributed in the range less than 30 km away from hydrocarbon expulsion center,and more than 50%of reservoirs are distributed in distributary channel facies.The reservoirs are all distributed in the area of which potential index is less than 0.8.40%of reservoirs are distributed under regional seal with thickness of 70~80 m.All the reservoirs are distributed within the area below 1.6 km from faults.There are 3 classⅠhydrocarbon accumulation plays in Fuyu reservoir in Qijia-Gulong Sag.Statistics shows that more than 85%of discovered fault-lithologic reservoirs are distributed in the classⅠaccumulation plays.The results play a guiding role in further exploration of Qijia-Gulong Sag.