This paper presents an original method for azimuthal residual velocity analysis in a context of wide azimuth acquisition geometry. The 3D analysis is performed on individual Common Image Gather and takes full advantage of the offset vector binning concept which preserves the offset and azimuth information in a consistent manner. The proposed azimuthal residual velocity analysis is based on semblance optimisation by scanning isotropic and anisotropic components of a parabolic elliptical model. The significant imaging improvement that we are seeing with our land data case demonstrates the accuracy of the extracted azimuthal parameters. The azimuthal residual moveout allows seismic events to be stacked constructively when strong azimuthal variations occur.

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High-density wide azimuth (WAZ) land surface acquisitions have demonstrated superior imaging capabilities. Apart from the traditional poor signal-to-noise ratio of land data we face a new challenge: the necessity of reconciling the kinematics of the various azimuths. In this paper, we present an imaging case history involving WAZ non-linear slope tomography. Using surface information (kinematic invariants), velocity model updates are performed both in depth and time. We chose to start from an initial pre-stack time migrated (PreSTM) dataset. After applying a structurally consistent filtering to improve the S/N ratio on stacked data, we used a dense automated tool for dip picking. In parallel residual move-out (RMO) was computed on all azimuths simultaneously. Our case study demonstrates that WAZ non-linear slope tomography in the depth domain greatly improves the imaging of the structures when compared to the initial PreSTM result. We observe that even if tomography in the time domain significantly enhances imaging, it cannot successfully honour the kinematics of the various azimuths within the constraints of time imaging assumptions. On the contrary, WAZ non-linear slope tomography in the depth domain offers an efficient way to reconcile these kinematics, thus promoting the use of depth imaging when processing high-density WAZ data, even in the context of mild geological complexity.

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