构造断阶对沉积的控制:来自地震、测井和露头的实例

Depositional Controls of Structural Fault Terrace: Examples from Seismic, Logging and Outcrop Data

构造断阶是裂谷盆地 (特别是裂谷盆地发育早期 )或断陷盆地边缘发育的一种构造样式 ,反映盆地边缘因断块差异沉降所形成的沉积斜坡地形的阶梯变化。在地震剖面可以解释出许多不同类型的断阶带 ,并在此框架下根据地震反射结构解释地震相和沉积相。构造断阶带的不同类型控制了不同的沉积样式。构造断阶的识别约束了地震解释的多解性。测井资料的运用可以证实断阶带的沉积控制作用 ,约束地震解释 ,也可以进行沉积微相及空间分布的精细研究 .地震、测井的实例分别来自松辽盆地徐家围子断陷和渤海湾盆地沾化凹陷。来自胶莱盆地野外露头的实例从另一方面证实了这种控制作用。与钻井或测井资料相比 ,露头资料具有连续性。露头的详细分析可得到构造断阶对沉积和地层结构控制的细节。构造断阶 (带 )与沉积作用关系的模式可以提供油气勘探的地质模型。

Structural fault terrace is a kind of structural pattern developed on the margins of rift(especially in the early stage of rift)or fault basins reflecting step changes of depositional relief of slopes formed by different subsidence of marginal blocks. Some different types of fault terrace zones are interpreted from seismic profile under which we interpret seismic facies and sedimentary facies. Different types of fault terraces control different sedimentary types. The using of fault terrace may constrain the seismic interpretation with multiple resolutions. Well logging data may be used to test and confirm the controls of sedimentation on the terrace zones constraining seismic interpretation, and to study some details about sedimentary micro-facies and spatial distributions. The examples from seismic and well logging data are from Xujiaweizi fault depression of Songliao basin and Zhanhua sag of Bohaiwan basin. The example from field outcrop in Jiaolai Basin confirms this controlling process. Comparing with drilling and logging data, the information from outcrop is continuous and the analysis of outcrop may reveal details of sedimentation and stratigraphic architecture under control of structural fault terrace. Models of fault terrace and sedimentation may be applicable to oil and gas exploration.