MAVO: A Free Matlab-Based AVO Analysis and Interpretation Application

Amplitude variation with offset (AVO) methods are commonly used to study seismic amplitude variations with respect to offset or angle and relate them to fluid and lithology types and changes. MAVO is a free Maltab-based program for AVO analysis and interpretation. The program allows the user to carry out AVO theoretical and real data analysis and interpretation. With MAVO, one can invert pre-stack gathers for AVO attributes such as intercept and gradient. The intercept and slope are combined to produce other AVO attributes related to fluid, such as different fluid factors and scaled Poisson ratio. As an application, Vp, Vs, and density models from the Marmousi II model are used to compute the AVO intercept, gradient, P-wave reflectivity, and S-wave reflectivity. The latter AVO attributes are combined to produce the first fluid factor (FF1) proposed by Smith and Gidlow (Geophys Prospect 35:993–1014, 1987), the second fluid factor (FF2) presented by Fatti et al. (Geophysics 59:1362–1376, 1994), and the third form of the fluid factor (FF3) proposed recently by Farfour and Castagna (A new expression for fluid factor using AVO intercept and gradient. Expanded Abstract in SEG21 91st Annual Meeting, 2021). The above attributes showed an excellent ability to detect the different hydrocarbon-saturated reservoirs in the Marmousi model. Therefore, MAVO will be an excellent tool for students and new AVO practitioners to practice AVO attributes and their uses for hydrocarbon-saturated reservoir detection.