THIN CLASIC SAND RESERVOIR PREDICTION BASED ON MATCHING PURSUIT SPECTRUM DECOMPOSITION-A CASE OF EASTERN DEPRESSION OF NORTH YELLOW SEA BASIN

To meet the needs in selection of target area and well locations for oil and gas exploration of thin classic sand reservoirs, it is very important to disclose the three dimensional distribution of sandbodies. In the Eastern Depression of North Yellow Sea Basin, fan deltaic deposits are well developed in the Cretaceous. The sand deposits usually come from multiple sources, having sharply lateral change in lithology and thin in thickness. Restricted by the frequency of seismic data, the seismic impedance inversion method is difficult to identify the thin reservoir. The matching pursuit spectrum decomposition technique, which has the advantages of fast computing speed and high time-frequency resolution, is found in this case of study the most favorable method for thin sand reservoir identification. In this paper, by analyzing the response of thin sand body of lower Cretaceous to the seismic in the well location, through picking up of the high frequency components after seismic frequency-broadening, which may distinguish the characteristics of the thin reservoir, then we carried out the matching pursuit for 3D seismic data spectral decomposition and seismic sedimentary cycle analysis, and make frequency-division interpretation on the high-frequency sequence stratigraphy. The results show that although the Early Cretaceous sand body is low in both porosity and permeability, the contents of finger-like fan delta plain sanstone is rather high. Hydrocarbon detection based on spectrum analysis proves that it is a favorable area for reservoir traps.