The application of seismic sedimentology in studying different sedimentary facies and reservoirs

Seismic sedimentology,which includes seismic geomorphology and seismic lithology,has wide application prospect. Based on investigations of three different depositional environments,i.e.,siliciclastics in the Karamay Formation of Mahu sag,carbonates rock in the Longwangmiao Formation of Central Sichuan Basin,and mixed sediments in the Jialingjiang Formation of Central Sichuan Basin,the paper discussed the application of seismic sedimentology in studying facies and reservoir in three systems,i.e.,siliciclastics,carbonates,and mixed lithologies(evaporates,carbonates,and siliciclastics). It is found that alluvial fan and fluvial river facies developed in the Karamay Formation. Reservoir in point-bar has a better porosity,permeability,and higher production than that in lower-fan. Sedimentary facies in the Longwangmiao Formation are controlled by syn-depositional strike-slip faults. Thick dolostone reservoir is located mainly on the upper slope area in Moxi structure. Lower part of second member of the Jialingjiang Formation in Central Sichuan Basin changes from non-marine facies in the southwest to mixed facies and restricted evaporite facies in the middle,and to marine faces in the northeast. Reservoir-bearing dolostone lithofacies are located near the middle evaporite facies. Besides of the typical phase rotation,strata slice,and frequency decomposition,two new techniques(principal component analysis and RGB blending)were applied to these three cases. The results are satisfactory,and it is proved that seismic sedimentology is effective to qualitatively reconstruct depositional facies and quantitatively predict reservoir.