Thin-layer reservoir prediction in the lower ESj of the western ramp of Qikou depression

Key words:  Qikou depression  Shahejie formation  thin-layer reservoir  lithofacies  bioclastic limestone  seismic colored inversion  reservoir prediction

Abstract:

The seismic reflection event of the lower Es, member in the western ramp of Qikou depression is a sort of comprehensive seismic response in complex lithology. Due to its poor isochronous properties, the reservoirs distribution cannot be predicted by technology of seismic reflection event and traditional inversion. According to the features of thin layer and quick changes in spatial of bioclastic limestone in the western ramp of Qikou depression, the lower Es, member of Shahejie formation was divided into three high frequency sequences cycles of fifth-order by sedimentary cycle analysis. Its sedimentary patterns in vertical sequence were concluded. Then, the continuous change of high impedance body in time-domain was detected by colored inversion amplitude map technique. Finally, large-scale li thofacies of every fifth-order cycle are reconstructed with the combination of geological and geophysical information on the guidance of sedimentary patterns，and the distribution of bio-clastic limestone in the layers with thickness of 3 ~ 9 m was predicted. The method of multi-information lithofacies reconstruction can lessen the risk of reservoir prediction effectively.