VSP-CDP stacking method and three-dimensional VSP coverage number calculation method

Abstract

The invention provides a VSP-CDP stacking method and a three-dimensional VSP coverage number calculation method. The method comprises the following steps: inputting rms velocity spectra of upstream waves and downstream waves; dividing imaging grids according to a three-dimensional rms velocity model, the grid spacing being the size of a three-dimensional surface seismic imaging grid, and sequentially finding corresponding receiving points according to the grids; laying a three-dimensional VSP observation system; applying binning iteration-based VSP-CDP stacking method to the calculation of coverage number of the observation system. The binning iteration-based VSP-CDP stacking method uses a lateral variation velocity field to replace a single well based velocity model, and a binning iterative method to replace a reflection point based analytical method. The VSP-CDP stacking method and the three-dimensional VSP coverage number calculation method provided by the invention have the advantages of further enhancing the accuracy of VSP stack imaging, ensuring that enough coverage number is obtained in a target area, and the time of acquisition design can be obviously reduced.

Description

technical field [0001] The present invention relates to the field of optimal design of vertical seismic exploration three-dimensional observation system, more specifically, relates to an improved three-dimensional vertical seismic profile (VSP)-common depth point (CDP) stacking technology and an improved VSP-CDP stacking technology A fast calculation method for 3D vertical seismic section coverage times. Background technique [0002] In order to overcome the defect of a certain angle limitation in the coverage area, a three-dimensional vertical seismic profile (collectively referred to as VSP) technology with omnidirectional excitation in the area around the well was developed. The 3D VSP data has high resolution and can image small structures that cannot be imaged by surface seismic in the area near the wellbore. The 3D VSP data is rich in anisotropy information, which can realize high-resolution 3D imaging around the wellbore, which is beneficial to the study of lithologi...

AI Technical Summary

Problems solved by technology

[0003] The calculation of 3D VSP coverage times usually adopts the ray tracing statistical method based on CRP coverage times. Since this method uses the ray method for depth domain modeling, it has the following deficiencies: ① It is difficult to establish an accurate depth domain model, and there is no lateral gradient in the layer velocity ;②Depends on the ray tracing parameters, the results will change with the parameters, and if the parameters are not filled in properly, there will be lighting blind spots;③Due to different statistical methods, there is a big difference between the number of CRP coverage and the number of coverage after acquisition, and there are differences in the imaging range. It is difficult to detect the accuracy of the design; ④ There are problems such as low calculation efficiency in the calculation of "3D" vertical seismic section coverage times

Images