A Particle Swarm Optimization Algorithm for Wave Impedance Inversion Constrained by Statistical Properties of Well Logging Data

Abstract

The invention discloses a logging data statistical property constraint-based wave impedance inversion particle swarm optimization algorithm. The algorithm comprises the following steps that: 1) phase correction is performed on seismic data, so that the seismic data can be a zero-phase record; 2) a wavelet amplitude spectrum is extracted, and seismic wavelets are obtained; 3) analysis and statistics are performed on velocity information based on existing logging data in a data volume or section, so that a feasible region for performing inversion operation to obtain a reflection coefficient, namely, the search space of the reflection coefficient, is established; 4) the improved particle swarm optimization algorithm provided by the invention is adopted to perform inversion operation to obtain the reflection coefficient; and 5) wave impedance is calculated on the basis of the reflection coefficient which is obtained through inversion operation. According to the algorithm of the invention, the constraint information of probability distribution is added to the reflection coefficient so as to overcome the multiplicity of the solution of the inversion of the reflection coefficient and improve the resolution of the inversion result, and therefore, the invariance of the probability distribution of the reflection coefficient which is obtained through inversion operation can be ensured; the prior information of the probability distribution for the inversion operation is completely derived from the actual logging data, so that the credibility of the inversion result is ensured, and the multiplicity of the solution can be reduced.

Description

technical field [0001] The invention belongs to the field of geophysical exploration, and relates to a wave impedance inversion particle swarm optimization algorithm constrained by statistical characteristics of well logging data. Background technique [0002] With the deepening of oil and gas field exploration and development, oil and gas exploration objects are becoming more and more complex, gradually shifting from simple structural oil and gas reservoirs to complex structural oil and gas reservoirs, and from structural oil and gas reservoirs to stratigraphic-lithological and other subtle oil and gas reservoirs. How to describe complex structures and strata in detail? Lithology is a key issue facing oil and gas exploration in my country. [0003] Wave impedance is an important parameter to characterize formation lithology. It is like a bridge connecting geology and geophysics. By studying the wave impedance information, reservoir parameters such as lithology, porosity, pe...

AI Technical Summary

Problems solved by technology

These algorithms have different principles and bases, and cannot replace each other.

However, the direct inversion of reflection coefficient by the traditional global optimization algorithm has problems such as multi-solution and low resolution. This is because the data we use for inversion is actual observation data, which has a limited bandwidth Subsurface geological structure and rock property information are broadband data, and these problems restrict the application of traditional global optimization algorithms in wave impedance inversion

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