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

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.