Wave Equation Based Diffraction Imaging by Dip-Dependent Wavefield Multiplication

Abstract

Summary An efficient and practical wave-equation-based technique is proposed to image subsurface geologic features such as isolated scatterers, reflector edges, faults, fracture zones, and erosional boundaries whose seismic expression is mainly characterized by diffracted waves. This technique has the ability to directly reveal and differentiate important geologic features compared to results obtained using reflected seismic waves. This new technique comprises of three steps. First, the source and receiver wavefields are decomposed into left- and right-downgoing propagating waves, respectively. Second, applying the imaging condition to the right-downgoing source and the right-downgoing receiver wavefields to generate the so-called right-right image. Similarly, a left-left image is generated. Third, the left-left and right-right images are multiplied sample-by-sample to form the final diffraction-based image. The key idea of this method is based on the fact that any dipping reflector will be present in either the left-left or the right-right image, whereas diffractor energy can exist in all dips i.e., both images. After multiplication of both images, only the diffractors remain while the reflectors are suppressed. The new algorithm has been successfully tested on two synthetic data tests shown here.