The dissertation focuses on seismic wavefield forward modeling and migration for the fractured reservoir . the paper integrates and researches the wavefield extrapolation operator for lateral variation of velocity , analysis of the wavefield characteristic , forward modeling and depth migration of prestack and poststack seismic wavefield , creation of wavelet , design of the model with fracture and cavity , and computation of reflectivity
2.
In term of analyzing and summarizing the existing achievement , propose an advanced and practical wavefield extrapolation operator and arithmetic of forward modeling and migration , which obtain numerical simulation and analysis completely and systemically and exploited new field of fractured reservoir seismic wavefield numerical simulation and applicationin in frequency - wavenumber domain
3.
A hybrid migration method , named " fourier finite - difference migration " , is a post - stack depth migration scheme . the downward extrapolation operator is split into three operators : one operator is a phase - shift operator for a chosen constant background velocity , another operator is the well - known first - order correction term , and the third operator is a finite - difference operator for the varying of the velocity function . phase - shift downward extrapolation and finite - difference downward extrapolation preserves the advantage of phase - shift method and finite - difference method
4.
Comprehensively discuss the issues in application , adaptive condition and performance , propose a fast arithmetic of forward modeling and depth migration in common shot gathers with one - way acoustic wave equation based on vrselrf , and verify the arithmetic by numerical simulation . concisely discuss the cause of the creation of evanescence and the problem of lateral amplitude discontinuity result from it . fourthly , use the reflectivity model , computed to describe the fracture model , with the formula of computation reflectivity based on elastic - acoustic approximation , and the wavelet model computed by the method , wavelet creation with fourier transform , we proposed , in conjunction with vrselrf wavefield extrapolation operator
5.
The paper concentrates on seismic wave - field forward modeling and migration for the fractured reservoir . it researches the wavefield extrapolation operator for lateral variation of velocity , design four theoretical models and seven practical models with fracture and cavity . base on the progenitor , in the frequency - wavenumber domain with the pspi wavefield extrapolation operator and arithmetic of forward modeling and migration that applied lateral variation of velocity which is strong , the paper obtains the result of numerical simulation and the wavefield characteristic by the way of the forward modeling and depth migration of poststack seismic wavefield
6.
Author , starts from the one - way wave equation of wavefield extrapolation , research the relationship and transform condition of wavefield extrapolation operators , and propose the steady variational reference slowness rytov approximation general screen wavefield extrapolation operator ( vrselrf ) which can adapt severe lateral velocity variations , in frequency - wavenumber domain , and the improved wavefield extrapolation scheme , also give the method to improve the computation efficiency . the achievement establishes the theoretic basis of the whole research
7.
Firstly , the paper starts from the one - way wave equation of wavefield extrapolation , research the relationship and transform condition of wavefield extrapolation operators , and improves on the wavefield extrapolation operator and so heightens the operation efficiency , and chooses the pspi that fits to the lateral variation of velocity to resolve the wave - equation , which lay a foundation of the theoretic study
8.
Author , secondly , starts from the approximate expandness of square root operator , perform mathematical calculations for finite difference operator in frequency - space domain , fourier finite difference operator in mixing domain ( frequency - space and frequency - wavenumber domain ) and general screen operator in mixing domain , compare and discuss their precision of their wavefield , adaptability for lateral velocity variations , computation efficiency and stability . thirdly , author , applies the steady variational reference slowness rytov approximation general screen wavefield extrapolation operator ( vrselrf ) in frequency - wavenumber domain , to the prestack and poststack forward modeling and depth migration
मोबाइल