Two-parameter expansion method and device confirming underground velocity structure

Abstract

The invention provides a two-parameter expansion method and a device confirming an underground velocity structure, and belongs to the technical field of seismic explosion. First, velocity of longitudinal wave scanning calculation is conducted to original seismic data to obtain a velocity spectrum and the number and the approximate position of a master stratum. An initial velocity field is obtained through speed analysis. An initial velocity ratio gamma field is set by using the initial velocity field, initial two-parameter velocity analysis and calculation are conducted to obtain an energy curved surface which changes along with two-parameter, namely, a two-parameter velocity spectrum. Then, two-parameter velocity analysis and calculation are further conducted to the selected two-parameter value on the two-parameter velocity spectrum to obtain a novel stack energy profile and a novel two-parameter spectrum. A point with high stack energy is selected on each velocity analysis position and each two-parameter velocity spectrum, the two-parameter field of the point is further confirmed, and an imaging formula is expanded by the two-parameter for imaging. At last, the two-parameter filed is used for acquiring the layer velocity of each layer, and the underground velocity structure is obtained.

Description

technical field [0001] The invention relates to the field of seismic exploration, in particular to a double-parameter expansion (PRO) method and device for determining underground velocity structures. Background technique [0002] In the prior art, there are two seismic wave velocity analysis methods based on the CMP (CommonMidPoint) theory, NMO (NormalMoveout, dynamic correction) and DMO (DipMoveout, dip moveout correction), among which the NMO method is the common center Point-draw gathers, use velocity, and through NMO, flatten the CMP time-distance curve to obtain NMO velocity. The central idea of ​​DMO is to use the transformation operator to transform the original seismic data with non-zero offsets into the coincident data of shot points and receiver points, eliminate the influence of formation dip angle, and improve the quality of stacked sections and the accuracy of underground velocity. Purpose. [0003] Compared with the above-mentioned methods, the two-parameter...

AI Technical Summary

Problems solved by technology

However, in the actual geological structure, the reflection interface is often inclined or even sharply curved. Therefore, it is difficult for DMO technology to eliminate the influence of formation dip angle during the actual seismic data processing, so as to obtain the theoretically defined zero-offset profile and the corresponding The true velocity of the medium, and there will also be seismic drift

Images