A method and system for predicting the thickness of sand-shale thin interbedded sand bodies

Abstract

The invention discloses a method and system for predicting the sand body thickness of a thin sand-shale interbed. The method comprises the steps of acquiring 90-degree phase seismic data and extracting 90-degree phase wavelets from the 90-degree phase seismic data; drawing, based on the 90-degree phase wavelets and a single sand body geological model, a relation template between a zero-crossing time interval of target sand body seismic reflection and the target sand body thickness; determining, by the use of the target sand body spatial distribution morphology, the zero-crossing time interval of the target sand body seismic reflection; calculating the target sand body thickness based on the zero-crossing time interval of the target sand body seismic reflection and the relation template. The invention can improve the prediction accuracy of the sand body thickness using the seismic data, improve the reliability of the thin interbed seismic data interpretation and reservoir prediction, and provide a decision basis for fine oilfield development.

Description

technical field [0001] The invention relates to the technical field of oil and gas geophysical exploration, in particular to a method and system for predicting the thickness of thin interbedded sand bodies of sand and shale. Background technique [0002] Thin interbedded sand-mudstone is an important reservoir of continental clastic rock deposits in my country. This kind of reservoir is characterized by a thin single sand body in the vertical direction, overlapping of multiple sets of sand bodies, fast pinch-out of sand bodies in the horizontal direction, and poor connectivity. , The deposition pattern is complex. Affected by wavelet interference at the interface of thin layers, the seismic response of this reservoir is generally the reflection of several sets of sand bodies contained in one or several events. Existing methods for improving the resolution of seismic data cannot separate the reflections of different sand bodies from the event. [0003] Prediction of thin san...

AI Technical Summary

Problems solved by technology

[0006] The 90° phase shift tries to perform 90° phase processing on the seismic wavelet, and the peak of the composite wave of a single sand body corresponds to the center of the sand body, so as to determine the superposition relationship of different sand bodies, but this technology does not eliminate the wavelet intervention

The wave peak amplitude moment of a certain layer of sand body also includes weaker reflections of other sand bodies, that is, it cannot completely recover the reflection of a certain layer of sand body alone, which is not conducive to determining the thickness and superposition relationship of sand bodies

The 90° phasing technology only enhances the spatial correspondence between seismic reflections and thin-bed sand bodies, and improves the reliability of sand body identification using seismic reflections, but does not improve the estimation accuracy of sand body thickness.

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