ADVANCES IN RESERVOIR CHARACTERIZATION USING 3-D SEISMIC ATTRIBUTES

Abstract

For the discovery of new oil and gas reserves or to continue producing oil from the existing oil reserves, reservoir characterization methods need to be improved and more and more details about the reservoir should be first gathered before the drilling of production wells. The Mumbai High Basin in the western offshore region of India is considered for the purpose of this study. The reservoir is identified using the bright spot technology and various seismic attributes are calculated to delineate the reservoir. Acoustic impedance is calculated using the Post-Stack Seismic Inversion of the data. Amplitude Variation with Offset and Well Log Interpretation has been done for the better understanding of the reservoir and the calculation of various petrophysical parameters like porosity, hydrocarbon saturation etc. The reservoir is hydrocarbon-bearing sandstone which contains low impedance gaseous sands. Since the reservoir contains thin beds (as found from the well log data) below the seismic resolution of one-quarter of the wavelength, the spectral decomposition method has been used to decompose time-domain seismic data into frequency domain data. The method of spectral decomposition has been found to be more efficient and yields better results of the area of the reservoir than the general seismic inversion method