Method for performing joint inversion on P-wave and S-wave velocity ratio of reservoir by utilizing P-wave and converted wave data

Abstract

The invention provides a method for performing joint inversion on the P-wave and S-wave velocity ratio of a reservoir by utilizing P-wave and converted wave data. According to the method, an inversion target function is constructed by adopting a concept that a gamma change rate acquired from gather seismic reflection information and a gamma change rate acquired from travel time information are infinitely approximate, and key parameters of the target function comprise a P-wave intercept, a P-wave gradient, a converted wave gradient and the P-wave and S-wave velocity ratio calculated according to the travel time information, and can be acquired from the actually input amplitude versus offset (AVO) information of a P-wave and converted wave gather and the travel time information, so that the target function can be rationally constructed, and a finally inverted P-wave and S-wave velocity ratio elastic parameter is accurate.

Description

technical field [0001] The invention relates to geophysical exploration technology, and more specifically, relates to a method for jointly inverting the velocity ratio parameters of compressional and transverse waves of reservoirs and identifying gas-bearing or water-bearing properties of reservoirs by using data of longitudinal waves and converted waves. Background technique [0002] In oil and gas detection and reservoir description, the elastic parameters of the medium are very important, and these parameters are related to lithology and fluid composition. The three most important parameters describing elastic media are compressional wave velocity, shear wave velocity and density. The conventional geophysical prospecting technique at present is to invert the above three parameters by using the P-wave AVO (Amplitude Versus Offset, whose amplitude varies with the offset) pre-stack gather. However, a large number of theoretical studies and practical applications show that i...

AI Technical Summary

Problems solved by technology

However, using the above inversion method, the inversion result is the rate of change of P-wave velocity, S-wave velocity and density ΔV p / V p , ΔV s / V s , Δρ / ρ, the P-to-S wave velocity ratio of the reservoir cannot be directly obtained, and the description of the elastic parameter characteristics of the reservoir containing different fluid components is not intuitive and accurate enough, and the interpretation is more complicated

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