Simple method of multi-parameter seismic inversion

Abstract

The invention relates to a simple multi-parameter seismic inversion method for improving the precision and the reliability of the conventional pre-stack seismic inversion with the help of the seismic wave elastic impedance, thereby simultaneously extracting a variety of formation parameters. The steps are as follows: full wave logging information is utilized; an acoustic impedance AI and an elastic wave impedance EI are determined; a CMP gather is converted into an angle gather, and part of the angles are stacked; the conventional pre-stack elastic impedance inversion process is utilized to respectively carry out the AI and the EI inversion of cross-well measuring line of small angle stacked data and part of the stacked data of the middle incident angles; the channel calculation of the EI and the AI data which are obtained by inversion is carried out, thereby obtaining the seismic attributes which are closely related to the elastic density ratio, the lithology changes and the pore fluid ingredients; the reservoir lithology and the properties of the pore fluid are determined. The simple multi-parameter seismic inversion method only needs the seismic data of near and middle angles, and other parameters are obtained through the channel calculation of the relationship between the elastic density ratio and the acoustic impedance, thereby improving the calculation efficiency and being used in the pre-stack inversion of the seismic data obtained by the vast majority of the collection conditions.

Description

technical field [0001] The invention relates to petroleum geophysical prospecting technology, which is a simple multi-parameter seismic inversion method for improving the accuracy and reliability of conventional pre-stack seismic inversion by means of seismic wave elastic impedance, and then simultaneously extracting multiple formation parameters. Background technique [0002] Seismic exploration is a geophysical exploration method that artificially stimulates seismic waves, records the propagation behavior of seismic waves in a certain way on the surface, and studies their propagation laws in the formation to find out the geological structure and lithological characteristics of the underground, and then find oil and gas fields. . [0003] The ultimate goal of seismic exploration is to comprehensively utilize the kinematics and dynamics characteristics of seismic waves to obtain as much comprehensive stratum information as possible and lithology information related to the st...

AI Technical Summary

Problems solved by technology

First of all, with the current acquisition standards, it is generally difficult to obtain medium and deep large-angle seismic data, while shallow large-angle information is seriously affected by NMO stretching. In fact, the data that can be used for inversion often contain extremely limited long-distance information; secondly, for more complex formations, the incident angle is likely to be relatively large or even exceed the critical angle. Again, similar to the AVO technique, the elastic wave impedance technique also uses the convolution of the amplitude of the primary reflection wave and the seismic wavelet to describe the change characteristics of the actual seismic amplitude, but when the incident angle is relatively large, the seismic record will be far away The mode-converted waves, multiple reflected waves, and effective waves interfere with each other, so that the actual amplitude on the seismic record is very different from the amplitude described by the elastic wave impedance. In addition, with the increase of the offset, the estimated The error of the remote seismic data is also getting bigger and bigger (the remote error can reach 7-10°, Barens, 2006), and the amplitude caused by data processing is becoming less and less fidelity, and the signal-to-noise ratio of the remote seismic data is low. Excessive application of remote information in the inversion will reduce the reliability of the inversion results (Mallick, 2001, 2006)

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