Curved Pseudo Elastic Impedance based on Elastic Attribute Rotation Scheme for Reservoir Petrophysical Property Prediction

Abstract

Seismic based reservoir characterization commonly attempts to estimate petrophysical properties of a reservoir from a combination of elastic attributes resulted from seismic inversion. Two most wanted main reservoir properties to be estimated are porosity variation and hydrocarbon saturation across the reservoir. A combination of acoustic impedance (AI) and the ratio between P- and S-wave velocities (Vp/Vs ratio) based on rock physics models had been used in the earlier study to form Curved Pseudo Elastic Impedance (CPEI) attribute. However, the approach involved a fourth order polynomial in the logarithmic domain of AI and Vp/Vs ratio. A much simpler approach of combining these elastic properties to form CPEI attributes which is based on attribute rotation scheme is proposed in this study. To illustrate the methodology, we applied to well and seismic data located in the Natuna Basin, Indonesia. Results show that better attributes correlation to porosity and hydrocarbon saturation variation is achieved.