In-well virtual source method

Abstract

The invention relates to the technical field of seismic exploration, in particular to an in-well virtual source method which comprises the following steps: S1, acquiring exploration data according toan exploration task; S2, constructing an in-well virtual seismic source and a ground virtual seismic source for the data acquired in the step S1 by adopting a reverse time invariance principle, and forming a single-shot record received by the ground excitation ground and a single-shot record received by the in-well excitation well through correlation or convolution operation; S3, forming a horizontal view angle and vertical view angle double-view-angle seismic section through conventional seismic data processing; and S4, analyzing the horizontal distribution range of the anomalous body by utilizing the horizontal view angle profile, analyzing the vertical distribution range of the anomalous body by utilizing the vertical view angle profile, and obtaining the spatial distribution range of the anomalous body in the exploration area through result simultaneous analysis. The geophysical characteristics of a medium in an exploration area can be displayed from a vertical view angle and a horizontal view angle, direct waves, reflected waves and multiple waves are used for comprehensive imaging, and the resolution ratio is high.

Description

technical field [0001] The invention relates to the technical field of seismic exploration, and more specifically, relates to a virtual source method in a well. Background technique [0002] Seismic exploration in an urban environment is a complex and difficult task, and conventional methods face many problems and challenges. First of all, there are environmental noises caused by traffic and irregular vibration in the city, which have a serious impact on seismic data acquisition, thereby reducing the accuracy of exploration; secondly, the urban shallow engineering geological conditions are complex, within a few meters from the ground, artificial structures and There are many pipelines, and the anisotropy of the medium caused by human factors is extremely large; moreover, the accuracy of urban geophysical exploration is high, the accuracy of conventional geophysical exploration is at the meter level, while the accuracy of urban geophysical exploration is at the centimeter lev...

AI Technical Summary

Problems solved by technology

[0003] It is difficult to carry out conventional seismic exploration in mountainous areas with complex terrain conditions. Even if it is carried out, it is difficult to achieve the purpose of exploration, and the exploration effect is poor, because the complex terrain conditions seriously affect the quality of data acquisition, and the complex geological structure affects the application conditions of data processing technology.

[0004] Well-well (or cross-hole) seismic wave CT tomography is suitable for application in urban environments or complex terrain conditions, but the well-well geophysical method has low construction efficiency, high cost, and small amount of information obtained from a single hole; in addition, from From a technical point of view, transmitted wave imaging is limited by the disturbance ratio of anomalies to travel time, that is to say, the scale of anomalies is too small compared to the inter-aperture distance, so it cannot be distinguished, and the main frequency of transmitted waves is relatively low, and the resolution of anomalies is low.

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