Rock physical model-based shale stratum anisotropy parameter prediction method

Abstract

A rock physical model-based shale stratum anisotropy parameter prediction method comprises the following steps: constructing an equivalent clay-fluid-kerogen mixture constructed by using a Backus average and anisotropy differential equivalent medium model DEM to obtain the equivalent elastic tensor of the clay-fluid-kerogen mixture; calculating the equivalent elastic rigidity tensor of a brittle rock debris mineral mixture by using a polyphase Hashin-Strikman average formula; adding the brittle rock debris mineral mixture to the clay-fluid-kerogen mixture, and calculating the equivalent elastic rigidity tensor of clay-rock debris by using an anisotropy self-consistent model SCA; adding a rock debris aperture fluid to the clay-rock debris mixture, and calculating the equivalent elastic rigidity tensor of shale by using anisotropy DEM; and calculating the anisotropy parameters of a shale stratum according to the equivalent elastic rigidity tensor. The method allows the shale stratum anisotropy parameter to be directly measured, and brings convenience for rock physical modeling and subsequent elastic parameter estimation of shale exploration.

Description

technical field [0001] The invention relates to an unconventional oil and gas geophysical exploration technology, in particular to a method for predicting anisotropic parameters of shale formations based on a petrophysical model. Background technique [0002] Compared with conventional sandstone reservoirs, shale has more complex mineral composition and pore structure, and exhibits very strong anisotropy. Although the anisotropy of shale has a significant impact on its seismic response (velocity, amplitude) and logging data (p-wave velocity, shear-wave velocity), it is usually difficult to directly measure anisotropy parameters in exploration. Therefore, it has brought great difficulties to petrophysical modeling and subsequent estimation of elastic parameters in related technologies of shale exploration. [0003] The petrophysical model is a good bridge connecting shale reservoir parameters (mineral composition, porosity, pore aspect ratio, organic matter abundance and mat...

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Problems solved by technology

[0005] However, due to the great differences in the physical properties of shale in different regions, the current petrophysical models for shale usually have certain limitations, so it is necessary to establish a universal shale seismic petrophysical modeling method

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