Exploration and application of near-surface modeling method by tomography and refraction constrained iterative inversion
The southwest piedmont of the Tarim Basin is one of the important exploration successor fields,whose sur-face is covered with extremely thick loess,with a thickness of over 500 m.The velocity changes rapidly in both verti-cal and horizontal directions,and the surface structure is complex.In order to improve the seismic imaging effect and address the issue of difficulty in meeting the accuracy requirements of surface models in complex surface areas,re-search has been carried out in areas such as fitting time depth curve template,tomography inversion,and refraction inversion.The results indicate that the comprehensive application of multiple surface modeling methods is an effec-tive way to improve the accuracy of near-surface models;the loess curve template can reflect the variation law of near-surface velocity in the continuous medium area;The near-surface modeling method by tomography and refrac-tion constrained iterative inversion can control the model accuracy error within 5％;step-by-step progressive tomo-graphy constrained inversion can expand the depth of credible velocity field by about 1 500 m.The above achieve-ments have guiding significance for constructing near-surface models of high precision and improving seismic imaging accuracy in similar exploration areas.
tomographyrefractionnear-surface modelingsouthwest of the Tarimloesssurface structureseismic imagingcontinuous medium
NETL
NSTL
万方数据
维普
