复杂曲流带识别标志及其内部点坝叠加接触模式

Boundary Distinction Mark of the Complicated Meander Belt and Stacking Mode between Point-bar Sandbodies within the Belt

以现代沉积为指导,通过岩芯、测井地质、地震沉积学分析研究复杂曲流带边界砂体类型及其内部结构特征,提出了识别地下复杂曲流带的典型标志,即曲流带边界处废弃河道的长度与曲流带边界的长度比值大于65%,尤其在曲流带凹岸一侧此比值超过85%。通过对比分析正演模型、测井地质剖面及分频后地震反射轴的波形及振幅,识别并总结出研究区曲流带内部主要发育点坝主体—初期点坝—初期河道边缘、点坝伊始—废弃河道、点坝伊始—点坝伊始、废弃河道—废弃河道、废弃河道—点坝伊始、末期河道—点坝等点坝间边界叠加类型,并在此基础上建立了研究区曲流带内部结构模式。

Taking modern deposition as a guide,this paper uses cores,logging geology and seismic geology technology to study the types of sand body on the meander-belt boundary and internal structure characteristics of complex meander belt.The typical feature of complicated meander belt is that the proportion of abandoned channel sand body was between 65%~95%on both sides of the boundary in the meander belt,and this ratio is greater than 85%in the concave side.Through the comparative analysis of the forward model,logging geology section and waveform and amplitude of seismic reflection axis after frequency division,the modes of boundary contact and superposition between point bars was summed up in this study i.e.meander belt:main body of point bar-initial point bar-early river edge,the beginning of point bar-the abandoned channel,the beginning of point bar-the beginning of point bar,abandoned channel-abandoned channel,abandoned channel-the beginning of point bar,the end of the river-point bar,etc.And then,the internal structure model of meander belt was established based on the contact and superposition architectures between point bars.