西北大学学报(自然科学版)

目的研究渤南洼陷同沉积断裂构造坡折带及其对砂体沉积的控制作用,进而有效预测砂体的展布。方法依据地震资料及钻井地质资料,研究高精度四级层序地层格架,确定同沉积断层生长指数,并分析相关的砂体相带与展布特征,总结同沉积断裂构造坡折带的控砂模式。结果对砂体起控制作用的坡折断层的生长指数均在1.2以上,小于此数值时断层无法控制砂体沉积。同沉积断裂组合方式及动态演化过程形成了"斗"字形构造坡折带控砂模式。结论渤南洼陷同沉积构造坡折断层十分发育,在其发育演化过程中,影响了古地貌格局和物源供应,控制了沉积体系的发育和展布。

Aim To study the syndepositional structural slope-break faults which well developed in Bonan sub-sag,influenced paleogeomorphologic landscape and sediment source,controlled the developping and distributing of depositional systems.Methods In the fourth-order sequence stratigraphic framework of Bonan sub-sag,the combination pattern of structural slope-break zone and the controlling effects on the development and distribution of sub-lacustrine fan are analyzed precisely.Results The phenomenon with different structural slope-break faults in the same structural slope-break zone was analyzed,which in turn control the development of sub-lacustrine fan in different periods,and different parts in the same structural slope-break fault and different connecting patterns of structural slope-break faults control the distribution of sub-lacustrine fan.Conclusion The controlling model is put forward for the first time,in which the sub-lacustrine fan is controlled by complex crossed structural slope-break zone.The quantitative predictive index for slope-break faults was discussed.