Converted Wave Pre-stack Migration Methods of Ground Seismic
|School||Chengdu University of Technology|
|Course||Earth Exploration and Information Technology|
|Keywords||migration one-way equation time consistency imaging principleSSF converted wave|
Seismic data migration is an important part of seismic data processing, whichis similar to the structure inversion,providing important material and the basis forfollow-up to interpreting the work carried out. At present, the conventional conversionof non-PP wave migration has achieved many results, and the support of the waveequation theory and the premise of the rapid development of digital computers,migration technics have been from poststack to prestack, from the time migration todepth migration,and to right severe lateral velocity, and construct complexunderground geological conditions, imaging is more and more precision, giving layerdivision of oil and gas instructions such of seismic interpretation work carried out to astrong guarantee.P-SV converted wave exploration method, relative to the P-P waveexploration, comprehensive utilization of the shear-wave information, higherresolution, and can take advantage of the shear wave polarization characteristics do thework of fracture prediction and conventional treatment is difficult to complete theresults, the other with the PP-waveeffective contrast to improve the reliability ofinterpretation. Likewise, similar to the PP-wave migration, the P-SV converted wavemigration has an important role in the converted wave exploration. But compared tothe PP wave migration, the P-SV wave migration have their differences anddifficultiesFor the point calculation for the wave field separation and CCP and CCPgathers extraction and other problems. This paper first introduces the P-P and the P-SVconverted wave migration history of the development, followed by the wave equationmigration theory-the continuation and imaging. The focus is described to adapt to thelateral velocity’s depth migration and adapt to the complex medium prestack migration.Mainly one-way wave equation for the wave equation. Migration have done on thebasis of established P-wave velocity model in continuation and imaging methods that described in this paper,evaluating the results, judgment of geological bodies homingeffect and the adaptability migration operator. Then writing on one-way wave prestackforward theory, Describing physical processes and geometric process of propagation ofwave field.Making wave equation continuation theory more clear, help furtherunderstanding of one-way wave theory, in theory, verify the correctness of P-P wavemigration test. Finally the establishment of the compressional and shear wave velocitymodel for the elastic wave equation to get X-component records, turning to the specialtreatment for some of the converted wave exploration (Migration)-wave fieldseparation and polarity problem,analyzing the results of forward and migration ofconverted wave, getting some of the characteristics of the converted wave section,andto raise some questions and future research directions.