Pseudo-acoustic inversion method and its application

In the study area, the oil reservoir is mainly of structural-lithologic type. Their lithology varies dramatically in both lateral and vertical directions. Additionally, oil-water relation of the reservoir is complicated and the seismic data are full of multiplicity, which makes it very difficult to predict the reservoirs. There is such an insignificant velocity difference between sandstone and mudstone that the acoustic curves cannot effectively reflect lithological characteristics of the strata. Therefore, the pseudo-acoustic curves are transformed from spontaneous potential curves, which will effectively reflect lithological characteristics, and be used for acoustic impedance inversion. The fractal interpolation, simulated annealing algorithm and sparse spike inversion algorithm with trend-bound are employed to perform seismic inversion, and better results are obtained in reservoir prediction.