High-angle crack prediction method and device

Abstract

The invention provides a high-angle crack prediction method and device. The method comprises the following steps: performing first azimuth anisotropy inversion on wide azimuth seismic data based on aconstructed isotropic low-frequency model to obtain a first anisotropy intensity and a first anisotropy direction, and performing longitudinal wave speed anisotropy analysis to obtain anisotropy of alongitudinal wave speed difference and a fast longitudinal wave speed direction; carrying out anisotropism fitting on the first anisotropism intensity and the longitudinal wave speed difference to obtain the anisotropism intensity based on the longitudinal wave speed difference; and establishing an azimuth longitudinal wave anisotropy low-frequency model according to the anisotropy intensity basedon the longitudinal wave speed difference and the fast longitudinal wave speed direction, performing secondary azimuth anisotropy inversion on wide azimuth seismic data by the azimuth longitudinal wave anisotropy low-frequency model to obtain a second anisotropy intensity and a second anisotropy direction, and analyzing the second anisotropy intensity and the second anisotropy direction to obtaina crack prediction result. According to the scheme, a technical problem that a reasonable low-frequency model cannot be provided in the anisotropism inversion crack prediction process in the existingmethod is solved.

Description

technical field [0001] The invention relates to the technical field of oil and gas exploration, in particular to a high-angle fracture prediction method and device. Background technique [0002] At present, the sweet spot parameters such as fracture distribution density and fracture direction, which are crucial for shale gas exploration and development, are still unable to be obtained. They can only be estimated in point form by drilling information, and quantitative fracture prediction cannot be carried out in the entire region. With the wide-azimuth seismic data The application of it promotes the study of seismic anisotropy, and can effectively solve the problem of HTI (Horizontal Transverse Isotropy), which is an anisotropic medium model consisting of a group of parallel oriented vertical cracks distributed in an isotropic medium. Anisotropy, the seismic wave propagates in this type of medium, and the characteristic that the velocity changes with the direction not only ch...

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Problems solved by technology

[0004] The embodiment of the present invention provides a high-angle fracture prediction method and device, which integrates the anisotropy difference information of the longitudinal wave speed into the low-frequency model to obtain the anisotropy information of the formation, thereby predicting the obtained fracture information and solving the problem of The technical problem that existing methods cannot provide reasonable low-frequency models in the process of anisotropic inversion fracture prediction

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