Near-surface characterization, challenges, and solutions for high-density, high-productivity, broadband vibroseis point-source and receiver survey - a case study

摘要

We present the results of the near-surface characterization for a 3D survey in thrust belt area in Sharjah, United Arab Emirates. The near surface is very complex, with steeply dipping layers, faults, extreme lateral and vertical velocity variations, and vertical velocity inversions: all these features challenge conventional, refraction-based seismic methods. Surface-wave analysis and inversion provide a geologically consistent near-surface velocity model. Integration and validation of the model using other near-surface data, such as analysis of refractions and upholes, is presented along with a workflow for integrating near-surface measurements and statics computation. The shallow earth model, besides being used for the near-surface perturbation corrections, is interpreted together with other measurements. We show that the near-surface complexity is not only a cause of distortions and perturbations in the deep seismic images. The near-surface characterization can provide geologically consistent models, with high spatial resolution to identify structural and lithological elements of the near surface, which can be used for geological modeling and in general exploration.