Seismic Wave-field Numerical Forward Modeling And Migration For The Complex Geological Body

Complex geological body is main types of complex oil and gas reservoir, and it'sirregular geometrical shape and acutely variable velocity have an effect upon theaccurate imaging of complex reservoir. The dissertation focuses on seismic wave-fieldnumerical forward modeling and migration for the complex geological body. Thepaper integrates and researches the wave-field extrapolation operator for lateralvariation of velocity, analysis of the migration velocity and the wave-fieldcharacteristic, numerical forward modeling, time migration and depth migration of2D/3D pre-stack and post-stack seismic wave-field. In term of analyzing andsummarizing the existing achievement, an advanced and practical wave-fieldextrapolation operator and arithmetic of the complex model building, numericalforward modeling and migration are advanced. Numerical simulation are achievedand it' s results are completely and systemically analyzed and then new field ofcomplex geological body seismic wave-field numerical simulation and application infrequency-wavenumber domain is exploited.Firstly, the dissertation describe complex 2D/3D geological body with theideology of block and advance scheme of block 2D/3D complex geological modelbuilding with the reference point and scheme of block 2D complex geological modelbuilding with the theoretical model. The block structure describe the complexfractured reservoir by approximately computing the apparent attribute parameter.Model building is the base of seismic wave-field numerical forward modeling andmigration for the complex geological body. Secondly, Numerical forward modelingand imaging of the complex compact carbonate rocks fractured reservoir are achievedby the Phase-shift migration (PS) and the Phase-shift Plus Interpolation migration (PSPI),and then summarize the characteristic of its wave-field. Numerical forward modelingand imaging of the 3D complex geological body are achieved by the Split-step Fouriermigration (SSF), and then summarize the characteristic of its wave-field. The resultshow that it is essential and important to research complex geological body by 3Dseismic prospecting. Thirdly, To seriously understand thought of mathematicalgeophones and equal-time stack principle with applications to seismic pre-stacking numerical forward modeling, the method of wave-field modeling of commonshot gather records based on Huygens's principle is put forward. The common shotseismic gathers records and common shot gather multiples records with complexgeological model are simulated by using one-way wave equation technique, and thencontrast and analyze the characteristic of wave-field. The result show that it is alsoimportant that high S/N ratio records can be efficiently obtained by the schemeswhich can simulate complex geological model and different sorts of complexmultiples and can help recognize the types of multiples and interpret the seismicstratum. Fourthly, the accurate velocity is the base of the accurate imaging and thevelocity error result in inaccurate imaging. To discuss the different effect on timemigration and depth migration of horizontal stratified model and complex fracturedreservoir caused by different migration velocity error, and the summarize the law ofeffect on migration by velocity error.