The Application of High Frequency Resonance Based on MPD in the Identification of Oil and Water Layer

Abstract

How to effectively identify the oil and water layer has been a difficult problem in the hydrocarbon indicator (HCI). It is generally believed that the oil layer has the characteristics of low frequency enhancement and high frequency attenuation on the frequency spectrum. But in the actual application, the amplitude and frequency characteristics of the thicker water layer are very similar to that of the oil layer, which makes it hard to distinguish one from the other. In this paper, in order to identify the oil and water layer, a new method basis on matching pursuit decomposition (MPD) is proposed. Firstly, the time-frequency analysis of seismic data is carried out though high precision MPD method. Through analyzing the instantaneous amplitude at different frequencies, we consider that the main difference of the oil and water layer in the frequency spectrum is at the high frequency band where the oil layer shows relatively strong amplitude characteristics. Secondly, base on the high frequency resonance (HFR), the high frequency bright spot attribute is calculated from the frequency division data in the high frequency range. In this new attribute, the water layer is suppressed by the strong amplitude of the oil layer. Finally, the results of the HCI are obtained by multiplying the new attribute with the −90 degree phase shift of the seismic data. The forward modeling test and actual application in Bohai oilfield show that the high frequency bright spot method is more effective in suppressing the water layer and identifying thinner oil layers compared with the conventional low frequency and high frequency attenuation methods of HCI.