Two-dimensional gravity gradient and seismic data joint inversion method based on unstructured grid

Abstract

The invention discloses a two-dimensional gravity gradient and seismic data joint inversion method based on an unstructured grid. The method comprises the following steps: obtaining gravity gradient abnormal data; dividing the underground half space into a plurality of triangular units; achieving forward modeling calculation of the two-dimensional gravity gradient and seismic sound wave data under the irregular grid; then obtaining independent inversion results of the two-dimensional gravity gradient and the seismic sound wave data under the irregular grid; introducing a cross gradient constraint function into the irregular grid to realize joint inversion of the two-dimensional gravity gradient and the seismic sound wave data under the irregular grid; and performing iterative computation for multiple times, and checking the inversion fitting degree until a high-precision inversion result is obtained. According to the method, irregular mesh generation is realized for a two-dimensional discrete space, an irregular target geologic body is better fitted, a cross gradient constraint function is introduced into an unstructured mesh, and combined inversion of gravity gradient and seismic data under the irregular mesh is realized.

Description

technical field [0001] The invention belongs to the technical field of geophysics, and in particular relates to a joint inversion method of two-dimensional gravity gradient and seismic data based on an unstructured grid. Background technique [0002] Gravity gradient exploration is based on the difference in density between the exploration target and the surrounding rock, and the geological structure characteristics of the underground space are studied by measuring the gravity gradient anomaly. Because of its advantages such as economy, large exploration depth and rapid acquisition of area information, it has been widely used in the fields of deep earth structure detection, regional geological structure unit division, sedimentary basin delineation, solid mineral and oil and gas resource exploration and other fields. Seismic signals record the response of seismic waves passing through different subsurface media, are sensitive to the wave velocity parameters of the media, and ...

AI Technical Summary

Problems solved by technology

However, as the depth increases, the sensitivity of the gravity gradient anomaly to the underground target body attenuates, and the vertical resolution is lacking; the seismic signal records the response of the seismic wave passing through different underground media, which is sensitive to the wave velocity parameters of the medium, and in dense ray coverage Areas with high vertical resolution

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