Poststack acoustic wave impedance inversion method

Abstract

The invention provides a poststack acoustic wave impedance inversion method and belongs to the oil gas and coal bed gas earthquake exploration and development field. The method comprises the following steps: (1) processing poststack earthquake data so that a frequency spectrum of the poststack earthquake data is matched with a frequency spectrum of an acoustic wave impedance acquired from log data and relative acoustic wave impedance data is obtained; (2) constructing an initial acoustic wave impedance model based on model inversion or a variation function; (3) carrying out forward modeling calculation on the initial acoustic wave impedance model so as to acquire synthetic earthquake data; (4) comparing the synthetic earthquake data and actual poststack earthquake data so as to calculate modification of the acoustic wave impedance model, using the modification to modify and update the initial acoustic wave impedance model so as to acquire an updated acoustic wave impedance model, then carrying out the forward modeling calculation on the updated acoustic wave impedance model so as to acquire synthetic earthquake data, taking the model as the initial acoustic wave impedance model, and repeating the step 4 so as to acquire a final inversion result.

Description

Technical field [0001] The invention belongs to the field of seismic exploration and development of oil and gas and coalbed methane, and specifically relates to a post-stack acoustic impedance inversion method. Background technique [0002] With the needs of oil and gas exploration and development, reservoir prediction and fine description have attracted more and more attention. There are more and more explorations and researches carried out around this purpose, and seismic inversion is the most important point. When the target of inversion is wave impedance, it is called wave impedance inversion. The current seismic impedance inversion is divided into two categories: post-stack inversion and pre-stack inversion according to the data used. According to the inversion method, it can be divided into direct inversion and indirect inversion. Direct inversion is to directly start from the seismic data and calculate the acoustic impedance. Indirect inversion is to start from an initi...

AI Technical Summary

Problems solved by technology

However, interpreting horizons directly from post-stack seismic data has low resolution on the one hand, and is also affected by the quality of seismic data on the other hand.

Although the stochastic inversion widely used at present can provide multiple models that meet the requirements of statistical parameters through geostatistical means, its lateral variogram is still affected by the quality of post-stack seismic data, that is, the measurement used to calculate the longitudinal variogram The resolution of the well and geological data does not match the resolution of the seismic data used to calculate the lateral variogram

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