High-resolution frequency division joint inversion method based on high-precision nonlinear inversion algorithm

Abstract

The method comprises the following steps: firstly, determining a frequency band division principle by utilizing logging data forward modeling analysis, then performing frequency division processing on actual data based on the division principle, converting the actual data into angle gather data corresponding to different frequency bands, then performing frequency division joint inversion by taking the angle gather data as input, and reasonably improving the weight of high-frequency seismic information, so as to improve the accuracy of the frequency division joint inversion. By comparing the final inversion result with the inversion result based on the original angle gather data, the method provided by the invention can further effectively improve the resolution of the inversion result and improve the thin layer depicting capability of the inversion result.

Description

technical field [0001] The invention relates to oil and gas fields, shale gas seismic exploration and reservoir parameter prediction methods, in particular to a high-resolution frequency-division joint inversion method based on a high-precision nonlinear inversion algorithm. Background technique [0002] Shale gas is an important replacement resource in the world, and its exploration and development technology has become a research hotspot and difficulty. With the continuous deepening of shale reservoir exploration, the resolution requirements for pre-stack AVA inversion results are also getting higher and higher. From the perspective of reservoir structure, most unconventional reservoirs dominated by shale are interbedded Structures, such as inter-salt shale oil reservoirs, have such interbedded sedimentary characteristics that they cannot be well resolved by seismic data with limited bandwidth. Aiming at this problem, relevant scholars have carried out a lot of research. ...

AI Technical Summary

Problems solved by technology

However, these methods are inefficient and difficult to apply to actual production

A large number of scholars have pointed out that the high-frequency information in seismic data separated by spectral decomposition technology can effectively identify such thin interbedded structures, but conventional inversion methods do not fully utilize this part of high-frequency seismic information

The frequency-division joint inversion method in existing production simply combines seismic data of different frequency bands with conventional linear inversion. Due to the influence of the accuracy and resolution of the linear inversion method, the final combination effect is far from satisfactory. High-resolution requirements for exploration and development of shale reservoirs at the present stage

In addition, although some scholars have realized the frequency division joint inversion based on the approximate formula at this stage, such as Zhang Fanchang et al. realized the simultaneous inversion of pre-stack AVA multi-frequency information based on the Aki-Richards approximate equation, but there is no specific principle of frequency band division. and the weight factor adjustment method of high-frequency seismic information for systematic research and elaboration

Unreasonable frequency band division and weight factor selection will distort the inversion results, which will cause the final inversion results to lose their reference value

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