Study On Application Of One-way Wave Equation Prestack Depth Migration

The wave equation pre-stack depth migration imaging is to resolve the problemsabout seismic imaging of complex geologic bodies in the strong laterally varyingcondition. The wave equation pre-stack depth migration can be divided into one-waywave pre-stack depth migration and two-way wave stack depth migration. The typicaltwo-way wave pre-stack depth migration is the reverse-time migration, which canadapt to any change of the velocity field without inclination limit. But it is lowefficiency requires high computer capacity. One-way wave pre-stack depth migrationapproximately decompose by two-way wave equation, but it has inclination limit, inother words, the propagation of seismic wave can be describe within some spreadangle. But its advantage is more efficient to adapt to imaging of geological conditionswith certain inclinations.One-way wave Pre-stack depth migration has high imaging precision compare toKirchhoff Pre-stack Depth migration, high efficient compare to two-way wavePre-stack Depth migration, and the method can meet the imaging requirements ofmost complex structure. Therefore, it has broad applied prospects in practice. In thepaper, the corresponding research results have been obtained, through to research thetheory of one-way wave Pre-stack depth migration, and analyst and test the keyparameters by a number of commercial software, including the following:1) Basic theory of wave equation pre-stack depth migration; the basic principlerealization, process and key parameters of phase shift+interpolation+correctionone-way wave pre-stack depth migration, finite difference one-way wave pre-stackdepth migration in frequency space domain, and step Fourier one-way wave pre-stackdepth migration.2) The basic method and process of pre-stack depth migration processing incomplex structure area, mainly include: seismic data pre-processing of complex surface structure(including migration datum, static correction, pre-stacksignal-to-noise ratio improvement, etc), migration velocity analysis and the basicprocess based on Kirchhoff integral method.3) Analysis of real data processing: In this paper, one-way wave pre-stack depthmigration processing were done on real seismic data, then it’s compared withKirchhoff pre-stack depth migration to demonstrate its effect. The result shows thatone-way wave pre-stack depth migration greatly improve the quality of the migrationimaging, all kinds of geological phenomenon are more clear, and it lays a foundationfor the follow-up detailed interpretation.