Multi-component converted wave fracture prediction method based on rank correlation analysis

Abstract

The invention provides a multi-component converted wave fracture prediction method based on rank correlation analysis. The predication method includes steps of selecting a calculation time window, intercepting the radial component and the transverse component of a to-be-handled sampling point according to the calculation time window; performing rank correlation analysis on the to-be-handled sampling point and acquiring a maximal rank correlation coefficient; judging whether the to-be handled sampling point has fracture development and determining the location of the fracture development; separating the radial component and the transverse component to the to-be-handled sampling point judged to have fracture development and acquiring a quick transverse wave and a slow transverse wave; calculating the anisotropy coefficients according to the time difference between the quick transverse wave and the slow transverse wave; repeating the steps from calculation time window selection to anisotropy coefficient calculation for the next to-be-handled sampling point until calculation on seismic data is completed. According to the invention, judgment is made on calculation results by adopting adiscrimination method, so that areas with distinctive non-development of fractures are removed and accuracy in fracture development statistics is improved.

Description

technical field [0001] The invention relates to the field of petroleum exploration, in particular to a multi-component converted wave fracture prediction method based on rank correlation analysis. Background technique [0002] Fractured oil and gas reservoirs are one of the key points of petroleum geophysical exploration research today, and how to accurately determine the existence of fractures in the underground is a difficult point among the key points. Judging from the statistics of developed oil and gas fields in the world, fractured reservoirs account for about half of the world's total in terms of oil and gas resources and production capacity. Identifying and characterizing fault and fracture systems is a critical step in reservoir evaluation, block evaluation, and enhanced oil and gas recovery. In the current fracture prediction methods, the commonly used method is to use post-stack seismic data to calculate attributes or attribute volumes such as coherence or curvat...

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Problems solved by technology

When the azimuth angle interval is large, the energy ratio detection method has insufficient detection accuracy for fracture direction, especially for shallow EDA media, due to the irregular and uneven distribution of sub-azimuth gathers, the calculation error is relatively large, so it is only suitable for wide Azimuth 3D Observation System

Both of the above two methods do not have a filtering mechanism for the calculation results, that is, the azimuth and time difference are also calculated in some areas where fractures are not developed, and drawn in the fracture development map

Moreover, due to the relatively expensive shear wave source and the low signal-to-noise ratio and resolution of the shear wave excited by the shear wave source, it is still difficult to achieve large-scale application by using a pure shear wave source for shear wave splitting exploration.

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