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Migration Velocity Error Analysis Based On The Acoustic Wave Equation

Posted on:2007-09-05Degree:MasterType:Thesis
Country:ChinaCandidate:J YangFull Text:PDF
GTID:2120360185469876Subject:Earth Exploration and Information Technology
Abstract/Summary:PDF Full Text Request
The acoustic wave equation depicts the physical principle of the wave phenomenon. This thesis bases on the acoustic wave equation, uses the wavefield extrapolation operator in frequency-wavenumber domain to analyze the migration velocity error.This article reviews the history of wave equation migration in the first place, then compares the advantages and shortcomings of many migration methods and discusses the theory and methods of frequency-wavenumber domain wave equation migration adapted severe lateral variation of velocity in detail.Further, author introduces the concept of many kinds velocity and their inherent physical meaning, and then discusses the theory foundation and methods of migration velocity error analysis based on the acoustic wave equation.Finally, author takes some numerical simulation tests to display the bad effect on wavefield characteristic caused by velocity error. Firstly, toward to the horizontal refl lector and dipping reflector, their migration imaging result are compared under the equal velocity error; Secondly, analyzes the sensitivity of reflector dip, reflector depth and the ratio of horizontal to vertical velocity to the velocity error; Thirdly, discusses the different effect on time migration and depth migration caused by migration velocity error and transform the result in frequency-wavenumber domain to compare the characteristic of wavefield; Fourthly, author studies the evanescent waves, analyzes its bad affection in accurate migration imaging under the condition of migration velocity error. Fifthly, through summarizes the above achievement, we obtain the small velocity migration method to improve the quality of imaging. Sixthly, slightly discusses the relationship between the velocity error, wave dispersion and the migration precision.The above researches are integrated so this article provides the idea and method of the migration velocity error analysis both in quantity and quality and then does comprehensively discussions of the problem in application, adaptive condition and performance, adaptive ability of many operators in migration imaging.
Keywords/Search Tags:Acoustic wave equation, migration velocity, wavefield extrapolation, forward modeling, time migration, depth migration
PDF Full Text Request
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