Sandstone-mudstone thin interbed prediction method and system based on seismic waveform inversion

Abstract

The invention discloses a sandstone-mudstone thin interbed prediction method and system based on seismic waveform inversion. The method can comprise the steps: determining sandstone speed, sandstone density, mudstone speed and mudstone density according to logging interpretation data, and then, establishing a plurality of kinds of sandstone and mudstone combination modes; calculating frequency-varying AVO response on the full frequency band of all sandstone and mudstone combination modes through a propagation matrix method; calculating a correlation value of the actual seismic data and the AVOresponse of all sandstone and mudstone combination modes to obtain a final key parameter; according to the final key parameter, determining a final sandstone and mudstone combination mode; and inverting the seismic data layer by layer and channel by channel according to the final sandstone and mudstone combination mode to obtain an inversion result of the whole seismic section. According to the method, inversion is carried out through a well-constraint-free method, the influence of well constraint is small, an inversion result has a reference value for sand layer combination, space distribution prediction and the like, and a basis can be provided for distinguishing the reservoir quality from the aspect of a sand layer structure in prediction of a favorable reservoir.

Description

technical field [0001] The invention relates to the field of seismic exploration and development of oil and gas reservoirs, and more specifically, to a method and system for predicting sand-mudstone thin interbeds based on seismic waveform inversion. Background technique [0002] Geophysical technology has entered from the early evaluation stage of exploration and development to the later stage of oilfield development. In terms of structural interpretation, it has changed from studying large fault structures and large-scale geological structural areas to identifying small faults and micro-scale structures that are easy to accumulate oil and gas; In terms of oil and gas reservoir prediction, the prediction accuracy of reservoirs has gradually improved from thicker reservoirs such as large-scale strata and sandstone formations in the past to thin layers or even thin interbedded structures. Due to the propagation effect and tuning interference effect of interlayer multiple wave...

AI Technical Summary

Problems solved by technology

For incident angles greater than 30°, seismic data are increasingly affected by wave propagation effects in heterogeneous complex media, resulting in unsatisfactory applications in the range of large incident angles

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