Summary
Seismic trace 90°-phasing is the key technique for seismic sedimentologic analysis. In China, continental basins are characterized by frequent fluctuations of lake level, multiple material sources and complex lithology; impedances are not distinct for different lithologies. Accordingly, a set of lithologic inversion methods based on constraint of relative impedance data volume has been proposed. Seismic traces are 90°-phased to obtain relative impedance volume, and then, fractal theory and Kriging technique are used to generate lithologic data volume through inversion. Field data and later drilling data have proved that this method can be used to distinguish various lithologies and also protect the features of lateral wave variations. Compared with slices by using 90°-phase data volumes, series of stratal slices obtained from lithologic data inversion can reflect boundaries and sedimentary evolution features of sedimentary systems more accurately. Together with drilling data, the method has helped to identify different sedimentary units in the delta-lacustrine sedimentary system in Bin-III, Es2 Formation, revealing the southern fans as key exploration targets in future.
