Study On Methodologies Of Stratigraphic Sequence Driven Seismic Inversion

Focusing on the interpretation of sedimentary interface and its internal composition changes, Sequence stratigraphy can build up a obvious corresponding relationship between the multi-scale seismic data phase space and the characteristic of reservoir. Therefore, we can benefit in improving the reliability of reservoir prediction and characterization by adding sequence stratigraphy interpretation to seismic inversion. This paper discusses the inversion strategy that using sequence stratigraphy to constrain seismic inversion. The qualitiative and quantitative application of sequence stratigraphy in seismic inversion are considered in the point of frequency division and model constraints. Then mult-sequence-scale inversion method and sequence diven inversion with seismic data are discussed.Seismic data is the the integrated response of the reflection characteristics which depends on different level sequence and it’s periodic structure. The different levels of sequence corresponded to different frequency band meets mosaic principle. Therefore, we implement the scale division within the seismic frequency band by utilizing the time-frequency analysis method. The scale of sequence can be a guide for us to divide the seismic data into different scale, then we will obtain the seismic data volume with scale of different level. In this research, we utilize the mehod wavelet transform to divide the siesmic into different scales during the course of frequency division process. The wavelet transform method effectively avoid phenomenon of aliasing produced the conventional window filter. The results inverted by nonlinear inversion method by utilizing the divided the seismic volume of different sequence scale reflect the characteristics of reservoir details better. The method of sequence driven inversion attempts to apply quatitative interpretation of sequence stratigraphy in seismic inversion. We present a workflow to integrate sequence stratigraphy and rock physics for quantitative seismic inversion. First we build a physical property model with high resolution through stochastic modeling, which reflects the soatial trends of seimentological properties interpretated by sequence stratigraphy. Then translate to elastic parameter model by using rock physics model and use this elastic model as the initial model of elastic impedance inversion to improve the vertical resolution and spatial sedimentary characteristic of inversion result. Considering the uncertainty of stochastic modeling, we modify the porosity model by iteration inversion to get better inversion result. The synthetic test and field data application verfy the validity of the method.