Method and device for quantitatively evaluating stratum heterogeneity

Abstract

The invention provides a method and device for quantitatively evaluating the stratum heterogeneity, and belongs to the field of oil and gas resource exploration. The method comprises the steps that waveform data in a depth interval is obtained; depth correction is conducted, a waveform coherent stacking method is utilized for treatment, and the longitudinal wave speed and transverse wave speed ofa stratum are obtained; a scattering attenuation quality factor and center frequency of the waveform data are calculated; the average longitudinal wave speed, the transverse wave speed and the disturbance quantity of the transverse wave speed are obtained; a random medium model is built; different correlation distances are selected, corresponding characteristics of a sound field of the random medium model are simulated by means of a finite-difference time-domain value, and scattering attenuation quality factors of the random medium model under the different correlation distances are calculated; a scattering attenuation quality factor chart of the random medium model is built; a measured data scattering attenuation quality factor is compared with the scattering attenuation quality factor chart, and the correlation distance of the depth interval is obtained. Accordingly, by adopting the correlation distance of rock, the heterogeneity of the rock is quantitatively evaluated.

Description

technical field [0001] The invention belongs to the field of oil and gas resource exploration, and in particular relates to a method and device for quantitatively evaluating stratum heterogeneity. Background technique [0002] From the earth's crust, mantle to core, heterogeneity is ubiquitous, and heterogeneity often means geological tectonic movement and the existence of oil, gas and mineral resources. Therefore, it is very important to quantitatively evaluate stratigraphic heterogeneity using existing technical means . [0003] Inhomogeneities of different properties have different effects on seismic waves. Inhomogeneities of velocity and density can cause waveform changes, phase / travel time and amplitude fluctuations, apparent attenuation of direct waves, and lead to coda waves and precursor waves. Example: Inhomogeneities in rock formations can produce longitudinal (P) and shear (S) codas, as well as transitional codas between the two. When there are cracks, dissolved...

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Problems solved by technology

However, there are few studies on the heterogeneity of small-scale (logging scale) rocks. At present, the heterogeneity of rocks is only qualitatively identified based on dipole acoustic logging data, and it cannot be effectively quantitatively evaluated.

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