High-order nonlinear AVO inversion based on estimated inverse operator

In an AVO inversion process, Zoeppritz linear approximation is widely utilized. However, the approximation shows a significant disparity with the exact equation when the two media across the interface vary dramatically because these equations are under the assumption of minor differences between the media. One possible approach to improve the accuracy is developing high-order approximations. This paper presents a new AVO nonlinear inversion method in which inverse operator estimation algorithm is utilized. Compared with conventional optimization-class inversion algorithms, this method is a direct inverse method and it owns its unique advantages. The inversion objective function uses high-order approximation Zoeppritz equation to improve precision when the elastic parameters between both sides of the interface vary dramatically. Ratio of the P- and S-waves' velocity is taken into account as well. Model tests and real data results show that AVO inversion based on inverse operator estimation algorithm owns a high stability and reliability. A better inversion result can be obtained when high order approximation and a changing ratio of the P- and S-waves' velocity are utilized. © 2016, Editorial Department OIL GEOPHYSICAL PROSPECTING. All right reserved.