Joint inversion of PP- and PS-waves based on the iteration of ratio of S-wave velocity and P-wave velocity

Du Qizhen1 Huo Guodong1 Chen Gang2

(1.School of Geosciences, China University of Petroleum (East China), Qingdao, Shandong, China 266580)
(2.Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang, China 834000)

【Abstract】If we do not have velocity information when extracting P-wave velocity, S-wave velocity, and density from EI (elastic impedance), k (ratio of S-wave velocity and P-wave velocity) is set to a constant, which is always different from real k. This assumption leads to errors in the inversion results. It is found that inversion of P-wave velocity, S-wave velocity, and density based on EI is unstable due to noise (lack of information of big incident angles). We analyze influences of k on inversion results by the parameter resolution matrix, and have found that P-wave velocity and density are hardly affected by k, and that S-wave velocity is very sensitive to k. Based on this point, we design a nonlinear k value iteration method to obtain first accurate k value, and then accurate S-wave velocity. Then we derive P-SV wave elastic impedance accurate (SEI) formula based on Aki-Richards P-SV wave reflection coefficient approximation formula. Finally we propose a joint iteration of k value to extract P-wave velocity, S-wave velocity, and density from EI and SEI. The proposed join inversion is tested on a four-layer model and Marmousi 2 model. The tests results show that k value can rapidly converge to its real value and inversed P-wave velocity, S-wave velocity and density are more accurate and stable.

【Keywords】 elastic impedance; parameter resolution matrix; shear wave velocity; k value iteration; joint inversion;


【Funds】 National Natural Science Fund Project (41174100, 41074087) National Science and Technology Major Project of China (2011ZX05019-008-08, 2011ZX05014-004-003HZ) China National Petroleum Corporation Project (2014A-3609)

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    [1]Connolly P. Calibration and inversion of non-zero offset seismic. SEG Technical Program Expanded Abstracts, 1998, 8: 182-184.

    [2]Connolly P. Elastic impedance. The Leading Edge, 1999, 18(4): 438-452.

    [3]Lu S M, McMechan G A. Elastic impedance inversion of multichannel seismic data from unconsolidated sediments containing gas hydrate and free gas. Geophysics, 2004, 69(1): 164-179.

    [4]Li C,Yin X Y, Zhang G Z, et al. AVO approximation elastic impedance equation and inversion based on incidence angle. Journal of Jilin University (Edition of Earth Science), 2013, 43(5): 1663-1671. (in Chinese)

    [5]Chen T S, Liu Y, Wei X C. Study on method of PP and PS waves joint AVO inversion. Journal of China University of Petroleum (Edition of Natural Science), 2006, 30(1): 33-37. (in Chinese)

    [6]Su Y, Cai Q X, Qin G S, et al. Discussion on selection of the k value in the elastic impedance equation. GPP, 2011, 50(4): 350-354. (in Chinese)

    [7]Veire H H, Landrø M. Simultaneous inversion of PP and PS seismic data. Geophysics, 2006, 71(3): R1-R10.

    [8]Du Q Z, Yan H Z. PP and PS joint AVO inversion and fluid prediction. Journal of Applied Geophysics, 2013, 90(3): 110-118.

    [9]Aki K, Richards P G. Quantitative Seismology: Theory and Methods. University Science Books, US(2nd edition), 1997.

    [10]Mahmoudian F. Linear AVO inversion of multi-component surface seismic and VSP data. University of Calgary, 2006.

    [11]Duffaut K, Alsos T, Rognø H, et al. Shear-wave elastic impedance. The Leading Edge, 2000, 19(11): 1222-1229.

This Article


CN: 13-1095/TE

Vol 51, No. 01, Pages 97-105+20

February 2016


Article Outline


  • 1 Introduction
  • 2 Linearization of EI and parameter resolution matrix analysis
  • 3 The k value iteration method for the extraction of P-wave velocity, S-wave velocity and density based on EI
  • 4 EI and SEI joint k value iteration parameter extraction
  • 5 Conclusions
  • References