安塞地区三叠系延长组层序地层分析

目的详细划分安塞地区延长组层序,论述层序演化特征,并分析层序对油气藏的控制作用。方法在对露头剖面、钻井岩心及测井曲线综合分析的基础上,结合层序界面识别、准层序组样式、层序的划分和对比、沉积体系域识别及其组合样式,划分层序并进行分析。结果把延长组化分为4个三级层序,分别对应长10—长9,长8—长7,长6—长4 5和长3 2—长1期沉积;层序1至层序4分别经历了湖盆形成及扩张期、鼎盛期、回返期、萎缩消亡期;区域规模的储层大都处在低位体系域中。结论层序控制着生储盖的组合、储层的展布及储层的储集性能。

Sequence analysis of the Triassic Yanchang Formation in the area of Ansai

Aim To study the sequences of the Upper Trissic Yanchang Formation,analyse the characteristic of sequences environment and oil reservoir in the area of Ansai.Methods On the basis of comprehensive analysing outcrop section,well core and well-logging date,the characteristic of different sequences and its evolvement are analyzed according to the characteristics of sequence boundarys,the patterns of parasequence,the partitionment and contrast of the Yanchang Formation sequences.the dying control function between the sequences.Results From the sequence 1 to sequence 4,the evolution of Ordos Basin develops from initially forming,expanding,most prosperously dominating,finally contracting to vanishing.The Chang 6 and Chang 2 oil pool mainly are distributed in the lowerstand system tract.Conclusion The sequence controled the combination of oil-generating strata,reservoir and cover rock,the distributing of reservoir and the capability of reservoir.