Study On The Method Of Seismic Attributes Analysis And Pseudo-Acoustic Impedance Inversion

Shahejie formation of Nanmazhuang of Raoyang sag is of great petroleum exploration potential with abundant hydrocarbon source rocks, well developed sandstone, good-quality reservoirs and advantageous source-reservoir-cap rocks combination conditions. The formation also has many sets of oil layers and the phenomenon of oil gas show is common, so there are many layers which can be explored. Because of the thin thickness and big lithologic variation of the target layer, it is difficult to illustrate the distribution form, range and the lithology thinning out boundary of the single sandstone to meet the demand of deciding the trap of channel sand precisely. And all of these bring great difficulties to sand body identification and reservoir identification.Accounting for the above mentioned reasons, under the known of geological condition of the work area、the stratigraphic comparison、the fine structural interpretation and the sedimentary facies belt in this paper, post-stacked multi attribute analysis technology, conventional inversion methods and pseudo acoustic wave inversion technique are used to predict reservoir in the area of shahejie formation of Nanmazhuang of Raoyang sag, which illustrates the distribution form, range and the lithology thinning out boundary of the single sandstone precisely, and improves the resolution of reservoir prediction.Under the guidance of seismic attribute analysis, the sensitive seismic attribute which has clear geological meaning in the work area is specify the energy ratio, root mean square amplitude, partial frequency energy,low frequency energy increment and attenuation gradient, in which the most sensitive attribute of identifying sandstone and mudstone is specify the energy ratio. The method of wave impedance inversion in this paper is global optimization rapid inversion method which is the combination of simulated annealing method and wide-band restriction inversion method. This method not only solves the non-linear problem of the data and model, but also improves precision of the reservoir prediction precision. Pseudo-acoustic impedance inversion is the key point and the difficult point. Combined with the conventional logging results, all kinds of logging intersection analysis are used. Pseudo-acoustic is constructed with the other logging curve of well identifying lithology, then pseudo-acoustic impedance inversion is implemented to do reservoir identification, reservoir distribution and development characteristics, which can highly improve the identification precision vertically and laterally. In this paper, the resolution of result of pseudo-acoustic inversion is higher, which has the coincidence of 0.9 with the well data. Meanwhile, pseudo-acoustic inversion can identify the meter level reservoir, which can prove that the method of pseudo-acoustic inversion with global optimization is credible and economic.The predicting results of seismic attributes and seismic inversion are combined with geological data、drilling data and logging data and dynamic production data to explain the predicting results objectively, so as to predict the vertical and horizontal distribution of reservoir stratum with high precision, and then it can be a reference for the reservoir stratum comprehensive forecast research in the other oil field.