Automatic Picking of Delays On 3D Angle Gathers

Migrated gathers are a key input for velocity model building and for subsurface characterization. Kinematic information is used for velocity model updates, and amplitude and phase attributes are used for the derivation of material properties. Conventional gathers are two dimensional: a vertical axis that is either time, time migrated or depth, and a horizontal axis that can be offset, or angle in the depth migrated domain. With wide azimuth acquisition the gathers are 3D by nature. The additional horizontal axis is the azimuth angle. The importance of the azimuthal information for short wavelength velocity determination has been demonstrated theoretically (Bartana et. al., 2009). The naive way of describing the 3D gathers is by a set of azimuth sectors, where the offsets or angles are binned at each azimuthal sector. In other words, the separation for azimuth sectors treats the 3D gather as a set of multi 2D gathers. In this work we show a different approach, in which the azimuthal information is represented in a continuous manner for the purpose of delay analysis. The method for representing the 3D angle gather and the delay analysis performed in this domain are described. The method is demonstrated on a synthetic example and on field data.