Pre-stack interpretation for seismic imaging of complex structures

摘要

The object of this thesis is the study of methodological rules that ensure a correct and complete extraction of kinematical information contained in 2D complex seismic data. We recall that 2D pre-stack interpretation results must be coherent surfaces in the 3D cube of 2D seismic data. We then analyze in detail the difficulties of interpretation in the time and depth domains and we emphasize the necessity of a coherent interpretation between both domains. We show that common offset depth migration, thus facilitating the interpretation. We propose to use the post migration stack as a guide for interpretation, due to its improved signal to noise ratio, combined with its kinematical properties that link it to the cube of pre-stack depth migrated data. Finally, using a velocity determination method based on reflection tomography, we first validate these interpretation principles on a quite complex synthetic data set, and then illustrate its intrinsic difficulties on a real data set. (author). 103 ref., 112 figs., 1 tab., 2 appends.