f Reduction of 3D Geometry - Generated Artefacts

In most land 3D surveys (and in some marine 3D surveys) the low density of source and receiver points results in amplitude and phase perturbations which, in the presence of multiple reflections or radial noise, can hinder the extraction of stratigraphic information from the data. Analysis of the generation of these perturbations has been studied: it was shown that the amplitude of the perturbation was a direct function of the size of the elementary pattern which by translation generates the 3D grid. Two types of action can be taken to protect the data from these artefacts: at the acquisition stage, a design that minimizes artefacts may be preferred. To help select a design, we propose simulating 3D stack using either synthetic Of real data. At the processing stage, In Severe cases, conventional prestack processing techniques may not provide a satisfactory cancellation of residual perturbations. Furthermore, a poststack geometryderived filter can reduce these perturbations.