The Applied Research Of The Seismic Facies Analysis Under Isochronous Stratigraphy Framework

With the rapid development of seismic technology, the method of seismic facies analysis diversifies, which include trace shape classification based on SOM(Self-Organizing Mapping) network technology and seismic facies volumetric analysis based on 3D multi-attributes data. For most geologists and geophysicists, they are looking forward to achieving as much information from the seismic data to reflect the real situation of the lithology, petrophysical properties and fluid of subsurface. To build an isochronous stratigraphic framework guided by seismic stratigraphy and sequence stratigraphy is a process that recovers the paleogeography features. By this method, we can extremely reduce the interruption of faults and other factors, and can have a better idea of palaeo-geomorphology and palaeo-sedimentary environment, which brings us much definite geological meaning.This article mainly focused on the basic theory of isochronous stratigraphic framework, and has elaborated the conception of UVT (palaeo-geomorphology time). Through UVT, the seismic data can perfectly be flattened by detecting several main isochronous sequence and faults. For the flattened seismic data, the longitudinal time means the geological time while the time slice reflects the isochronous depositional plane. The main technology used in the article are the method of seismic facies analysis, involving SOM(Self-Organizing Mapping) network technology and multi-attributes facies analysis of seismic volume. Here, the main algorithm have been introduced to our research are trace shape classification ,principal component analysis and hierarchical clustering technique. Comparing the results of the seismic facies under non-isochronous stratigraphy framework with the results under isochronous stratigraphy framework, we have finally built a method and procedure to analysis the seismic facies under isochronous stratigraphic framework. The result from seismic facies volume can well highlight its geological characteristics both horizontally and vertically, especially the characteristics of the interior of some sedimentary bodies such as organic reef.We introduced the technology mentioned above into the research on reservoir characterization of organic reef of Changxing formation in northeastern Sichuan, and the good results have been achieved. After compared the results of the seismic facies under non-isochronous stratigraphy framework with the results under isochronous stratigraphy framework, we concluded that a seismic facies results under isochronous stratigraphy framework can relatively better reflect the sedimentary features and the formation of the geological bodies.