A graphical approach to determine the relationship between intercept, gradient, and the common seismic rock properties: Global model and application

Abstract Globally applicable forward amplitude variation with offset models of sand-shale systems are displayed using the interceptgradient crossplot, color coded by the magnitude of reflectivity of the common seismic rock properties: bulk modulus, shear modulus, Lamé's parameter lambda, Poisson's ratio, and VP/VS. Lines of equal magnitude are threaded through the data to establish the angular relationship of each rock property to intercept and gradient. In many cases, these generic models will be sufficient to design a seismic inversion capable of distinguishing lithology and fluid. An inverted seismic section over a producing field illustrates how fluid-sensitive (rEEIχ27) and fluid-insensitive (shear-impedance) attributes conform closely to the generic model. Where suitable data exist, the modeling process can be modified to provide a more tailored reservoir characterization and inversion routine.