Application of converted-wave PreSDM for PP-PS joint inversion study in the Junggar Basin, Northwest China

Summary Picking PP and PS sections for registration is required for PP-PS joint inversion of PreSTM gathers. Because of the characteristic of PS-wave propagation associated with lower velocity and frequency content, weaker reflectivity and possible polarity reversal, manual picking based on data similarities is not reliable enough to derive an accurate background Vp/Vs model. To avoid this problem, PS anisotropic PreSDM is employed that takes advantage of non-linear slope tomography. This provides depth-consistent PP-PS imaging, and an initial Vp/Vs model for joint inversion. In this paper, we describe a successful application of PreSDM-based PP-PS joint inversion in the Northwest of China. We show that a lower Vp/Vs ratio occurs in oil-bearing sandstones compared with dry sands in this area. Also, we conclude that PreSDM-based PP-PS joint inversion offers an efficient workflow and more accurate elastic attributes than PreSTM.