Method and device for analyzing dispersion and attenuation of unsaturated double-porosity medium earthquake waves

Abstract

The invention discloses a method and a device for analyzing the dispersion and attenuation of unsaturated double-porosity medium earthquake waves. The method comprises the following steps of: 1, acquiring geological data including penetration rate, porosity, shale content and mineral components and generating a reservoir rock dry framework model according to the geological data; 2, acquiring measured data including drilling data, logging data, logging information and fluid experiment measured data and generating a reservoir fluid model according to the measured data and a Van derWaals equation; 3, solving plane waves according to the reservoir rock dry framework model, the reservoir fluid model and a Biot-Rayleigh equation for describing the spread of the unsaturated double-porosity medium earthquake waves, and generating phase speed and inverse quality factors of longitudinal waves and horizontal waves; and 4, generating relationships between frequency and each of speed, attenuation,wave impedance, AVO (Amplitude Versus Offset) response characteristic and the like according to the phase speed and inverse quality factors of the longitudinal waves and the horizontal waves.

Description

technical field [0001] The invention relates to a seismic rock physics model and a seismic wave numerical simulation technology in geophysical exploration, in particular to a method and device for analyzing seismic wave dispersion and attenuation in an unsaturated double-porous medium. Background technique [0002] The sedimentary rocks of the upper crust generally have a certain porosity during the formation process. With the increase of the depth from the surface, the porosity of the rocks will be significantly reduced under the action of compaction, consolidation and filling. However, the locally high-porosity sand Layers will still create conditions for the accumulation of gaseous hydrocarbons. Below the aquifer, it is very common for rock pores to be saturated with gas and water two-phase fluids at the same time. Therefore, it is necessary to deeply explore the physical properties of unsaturated rocks such as elasticity, resistivity, and magnetism for practical earth ex...

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Problems solved by technology

[0007] (1) In the related research based on viscoelasticity theory and BISQ theory, due to the introduction of some parameters or coefficients that do not have clear physical meaning or are not easy to realize directly physically (such as various relaxation times, viscoelastic coefficients or characteristic jet flow length, etc.), so that although these theories are very effective in the description and prediction of rock wave velocity phenomena, the mathematical basis and physical connotation of related theories and core parameters are difficult to be realized or verified. It is difficult to be popularized and applied in practical engineering

[0008] (2) In the related research of numerical simulation and seismic response analysis based on fine models, due to the need to establish an overly detailed rock model and set boundary conditions, although this type of method can accurately give the seismic wave response in the actual rock, However, in actual engineering, due to the lack of sufficient prior information, and due to the high complexity of modeling and the high consumption of algorithms, such methods cannot be well implemented in actual engineering applications.

[0009] (3) Some seismic rock models use statistical thermodynamic relations in the derivation process of dynamic equations, so that some core parameters of the equations can only be estimated by the upper and lower limits of the relationship in the frequency domain during the calculation process, but cannot To achieve more accurate quantitative prediction of seismic response

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