Prestack density inversion using the Fatti equation constrained by the P- and S-wave impedance and density
Liang Li-Feng1,2, Zhang Hong-Bing1, Dan Zhi-Wei2, Xu Zi-Qiang2, Liu Xiu-Juan2, and Cao Cheng-Hao1
1. College of Earth Science & Engineering, Hohai University, Nanjing 210098, China.
2. CNOOC Energy Development Engineering Geophysical Prospecting Institute of Technology, Zhanjiang 524000, China.
Abstract Simultaneous prestack inversion is based on the modified Fatti equation and uses the ratio of the P- and S-wave velocity as constraints. We use the relation of P-wave impedance and density (PID) and S-wave impedance and density (SID) to replace the constant Vp/Vs constraint, and we propose the improved constrained Fatti equation to overcome the effect of P-wave impedance on density. We compare the sensitivity of both methods using numerical simulations and conclude that the density inversion sensitivity improves when using the proposed method. In addition, the random conjugate-gradient method is used in the inversion because it is fast and produces global solutions. The use of synthetic and field data suggests that the proposed inversion method is effective in conventional and nonconventional lithologies.
This research work is supported by the National Nature Science Foundation of China (Nos. 41374116 and 41674113) and the project of CNOOC (No. CNOOC-KJ 125 ZDXM 07 LTD NFGC 2014-04).
Cite this article:
. Prestack density inversion using the Fatti equation constrained by the P- and S-wave impedance and density[J]. APPLIED GEOPHYSICS, 2017, 14(1): 133-141.
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2017, Vol. 14 
