AVAZ Quantitative Interpretation Based on Orthorhombic Medium-Part Two: AVAZ Inversion

In this paper, we mainly talk about orthotropic AVAZ inversion technique, it has proven to be important and effective for shale gas evaluation and development. We use pre-stack AVAZ inversion to predict elastic properties, it is carried on pre-stack azimuthal gathers with constrained wells. A slight modification was made on the basis of Bachrach’s (2004) equation in order to obtain elastic parameters such as P-wave impedance, S-wave impedance, combinations of anisotropic parameters and fracture orientation from inversion. This work could offer multiple elastic parameters that characterize the quality of shale reservoirs. This method is successfully applied in real data of Sichuan Basin, it shows that the results of inversion are effective and reasonable.