Over the last few years, a multitude of new and different AVO (Amplitude Variations with Offset) and pre-stack inversion techniques have been developed, all of which put a slightly different spin on the way we extract lithological and fluid information from pre-stack seismic data. These methods are as diverse as intercept versus gradient cross-plotting, lambda-mu-rho (LMR), simultaneous pre-stack inversion and Extended Elastic Impedance (EEI). For the working interpreter, keeping track of all of these different methods and how they relate to each other has become an almost impossible task. This talk will review a range of AVO and pre-stack inversion methods, describe their strengths and weaknesses, and also discuss how they are related. The talk will show that the fundamental concept behind AVO is the reflectivity derived from a physical earth parameter, and that the fundamental concept behind pre-stack inversion is the earth parameter itself, which is usually some type of impedance.

The presentation will stress the fundamental geology and geo-physics behind each method, and case histories from various basins around the world will be used to illustrate the methods. In particular, one of the case histories will focus on how pre-stack inversion can help in the delineation of sweet spots in the Haynesville shale play. This case study will focus on some of the newer inversion techniques which can estimate anisotropic earth parameters.