Prestack high-resolution fluid factor inversion method based on frequency division joint inversion

Abstract

The invention provides a prestack high-resolution fluid factor inversion method based on frequency division joint inversion. The prestack high-resolution fluid factor inversion method comprises the following steps: rewriting an accurate Zoeppritz equation in a traditional form based on a pore elasticity theory to obtain an accurate Zoeppritz equation in a new form containing a fluid factor item; constructing a multi-wave data frequency division joint inversion target function under a Bayesian framework by utilizing a frequency division processing result of actual seismic data of a work area, apriori distribution function of a plurality of reservoir parameters obtained by logging data statistics and a derived new form Zoeppritz equation; solving the target function by using Taylor series expansion to obtain a solving expression of the reservoir parameter disturbance quantity; and carrying out iterative solution on the solution expression, and carrying out iterative updating on the initial reservoir parameter value by utilizing a solution result until an iterative termination condition is reached. The prediction precision of the reservoir fluid factor can be improved.

Description

technical field [0001] The invention relates to an oil and gas field seismic exploration and development and reservoir parameter prediction method, in particular to a pre-stack high-resolution fluid factor inversion method based on frequency division joint inversion. Background technique [0002] Reservoir fluid identification is one of the important links in the exploration and development of oil and gas reservoirs, which is directly related to the "sweet spot" prediction of unconventional reservoirs such as tight sandstone reservoirs and shale reservoirs. Reliable fluid identification results can improve the success rate of exploration and reduce input costs, which is of great significance to the exploration and development of oil and gas reservoirs and reservoir evaluation. Usually, it is most direct and accurate to use core and logging data to analyze the fluid-bearing conditions of the reservoir, but this must be based on a large number of core samples and logging data ...

AI Technical Summary

Problems solved by technology

At present, the fluid factor is mainly estimated by the inversion method based on the exact Zoeppritz equation linear approximation formula, but the approximation formula has many assumptions, and there are large calculation errors in the case of strong impedance difference and large incident angle, which makes the fluid factor The accuracy of inversion results cannot meet the requirements of fine characterization of actual reservoirs

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

[0003] In summary, the current research on fluid factor seismic estimation methods based on prestack seismic data has

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