大陆边缘沉积盆地流体逸散管道地震特征及其成因机制

    SEISMIC CHARACTERISTIC AND GENETIC MECHANISM OF FLUID ESCAPE PIPES IN SEDIMENTARY BASINS OF CONTINENTAL MARGIN

    • 摘要: 流体逸散管道是深部流体向上运移所形成的通道,在大陆边缘沉积盆地中广泛发育。由地震资料显示,流体逸散管道主要由根部、过路区和末端3部分组成。由于形成机制、起源和流体成分的不同,其组成三要素有不同的表现形式,因此,流体逸散管道类型多样,具有不同的地震反射特征。水力压裂是文献中最常见的一种有关流体逸散管道形成机制的解释,但是,随着地震勘探的发展和研究的不断深入发现,水力压裂不足以解释所有类型的流体逸散管道,还存在其他的成因机制,包括流化侵蚀作用、局部空洞坍塌及同沉积模式等。从流体逸散管道组成三要素的角度描述了不同类型流体逸散管道的地震反射特征,并详细论述了其4种成因机制下的形成过程。

       

      Abstract: Fluid escape pipes, which are defined hereby as the highly localized vertical to sub-vertical pathways of focused fluid venting from some underlying source region, are developed widely in sedimentary basins of a continental margin. In seismic protiles, a fluid escape pipe can be divided into three components: root zone, leakage zone and pipe terminus. There are many types of fluid escape pathways and their components because of the difference in forming mechanisms, sources and fluid types. Therefore, Fluid escape pipes of different origin have different seismic characteristics. Hydraulic fracturing is frequently proposed as the mechanism for pipe formation. However, with the development of seismic exploration, we find out that hydraulic fracturing only is not enough to explain the formation mechanism of all types of pipes. There are other forming mechanisms including erosive fluidization, local subsurface volume loss collapse and syn-sedimentary process. The paper described the seismic characteristics of different pipes from the perspective of the three components of a fluid escape pipe. The formation processes of the four kinds of genetic mechanisms are also discussed in details.

       

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