Optimization of Infill-shot Layout Based on Target Illumination Analysis

The surface and target reflector shooting methods are two ways of determining infill-shot geometry based on targets, and both methods have advantages and disadvantages. This paper presents a new method that utilizes the advantages of both methods in order to optimize the infill-shot design. The target layer’s weak-illumination areas (shadow zones) resulting from the conventional geometry are determined through 3D geological modeling and seismic illumination analysis. Then, the target reflector shooting method is used to calculate the ray amplitude density map on a surface relative to the weak-illumination area, and this map is used to determine the initial locations of the infill shots. Finally, the surface shooting method is used again to select infill shots that have maximum illumination strength on the shadow zones of the target reflector. In summary, the optimized geometry is determined by adding these selected infill shots to the conventional geometry, and this optimized geometry both fits the constraints of seismic field operations and effectively improves illumination in target shadow zones using fewer infill shots.