Seismic facies analysis and reservoir characterization based on isochronous stratigraphy frame

Abstract

The concepts and methodologies of sequence stratigraphy or seismic stratigraphy have been applied in the seismic facies analysis and reservoir characterization based on seismic data. But one of the most important factors for getting good results in this kind of application is the coupling of seismic sequence and sedimentary sequence. Our study has showed that more accuracy and meaningful results can be achieved from seismic facies analysis and reservoir characterization based on isochronous stratigraphy frame compared with the results from diachronous stratigraphy frame. By comparative researches, we develop our own seismic facies analysis and reservoir characterization approaches under isochronal stratigraphy frame which mainly include (1) identifying the seismic terminations as the top and bottom of one large sequence stratigraphy, (2) reconstructing the seismic volume to build iso-geological time frame, (3) doing seismic facies volumetric analysis on this new geological time equivalent frame, and (4) identifying the inter detailed sequences and the interior of reservoirs by well log calibration to get final results about the distributions of sedimentary sequences, variation of reservoirs in 3D, etc.. The proposed approaches have been applied to several studies of the carbonates reef and shoal reservoir characterization aiming for gas exploration in eastern Sichuan Basin. The results from our studies have proved that the proposed methodologies and workflows are valid and better results have been achieved.