Application of seismic sedimentology to the western slope of northern Songliao basin

Abstract

During the sedimentary period of Saertu reservoir on the western slope of the northern Songliao basin, delta front and shore-shallow lake subfacies are mainly developed, which have the characteristics of few sandstone layers and thin single layer thickness. The lithology of thin layer or thin interlayer can not be distinguished clearly by seismic response on conventional seismic section, and it is difficult to identify them. Geophysical response characteristics of channel sand bodies are defined by well-seismic combination. Under the guidance of seismic sedimentology, the qualitative and quantitative prediction of channel sand bodies is carried out by using 90°-phase conversion, stratal slicing and waveform indication inversion techniques. The results show that the seismic reflection axis is symmetrical with respect to the top and bottom surface of sandstone, and the channel sand body has obvious characteristics and completely corresponds to wave peak reflection. The channel bodies of S1 and S23 reservoir formation are separated respectively into two stages by using the amplitude attributes of stratal slices, and the coincidence rate of reservoir prediction to wells is 78%~84%, with an average of 79.7%. The waveform indicator inversion technique is used to predict the channel sand body thickness of the four stages, and the error of sand body thickness to well is 0~1.6m, with an average of 0.32m.