| In the underground geological exploration of actual seismic wave has the characteristics of elastic wave,elastic wave can be decomposed as wave component,so we adopt elastic vector wave exploration technology,vector wave consists of PP and PS wave,at the same time imaging can get abundant wave field propagation information,the PS wave seismic tomography can provide complementary information for subsequent seismic interpretation,At the same time,longitudinal and transverse waves can provide more important geological information,such as:PP wave in reflection wave exploration is mainly used for underground structure interpretation,and PS wave in vector wave is mainly used for underground rock mass internal micro-structure.At present,velocity tomography can be divided into wave tomography(such as full waveform inversion)and ray travel time tomography according to its wave characteristics and kinematic characteristics.In industry,ray chromatography is relatively mature and practical,and prestack depth domain migration is more applicable than prestack time domain migration for practical production.In this paper,the travel time tomography method of elastic vector wave which is suitable for prestack depth Gaussian beam migration of elastic wave is adopted.Gaussian beam migration is the wave equation prestack depth domain focused on highfrequency solutions in the field of radiation,the gaussian beam offset can calculate the medium transmission of ray Angle information,obtained by gaussian beam deviation Angle domain common imaging point gathers for travel time residuals,and optimize the Angle gathers and horizon of loot,Langan method is adopted to improve the flexibility of vector wave get sensitivity matrix grid ray tracing,At the same time,horizon information is added for inversion constraints.Firstly,track aggregation information and horizon information of the Angle domain are picked up and fitted by the amplitude information,and then travel time residuals and grid tomography horizon constraints are obtained.Based on the uniqueness principle of Radon transform,the joint iterative equations of elastic vector wave velocity tomography were constructed.Finally,LSQR was used to iteratively calculate the velocity updating quantity and carry out the tomographic updating of the velocity field.This paper mainly studies the elastic for elastic wave migration method vector wave velocity tomographic method analysis and inversion problem,whether through Angle domain set is flattening,as the important basis of velocity tomographic update accurate or not,through several classical model and actual data test,vector wave velocity tomographic inversion method presented in this paper the effectiveness and applicability.At the same time,we verify the feasibility and correctness of the ray travel time vector wave velocity tomography method based on the angular domain track set in this paper through model tests. |
