Inversion to Common Scatterpoint Gathers and its Application in Time-domain Velocity Analysis and Imaging

Abstract

Common ScatterPoint (CSP) gather has several advantages over Common MidPoint (CMP) gather, such as higher fold and larger offset range, which enables better focusing of the velocity semblance and accurate velocity analysis. CSP gather sorting is a linear mapping process using the Equivalent Offset Method (EOM). Direct implementation of EOM might introduce coherent mapping noise, which will smear the velocity spectrum and decrease the imaging resolution. In this abstract, we recast the mapping process under the framework of least-squares inversion, which we call Inversion to CSP (ICSP). Compared with conventional CSP forming method, ICSP method can provide noise-free CSP gather and subsurface image with higher resolution by Normal Move-Out (NMO) and stacking. Compared with least-squares prestack time migration, ICSP method is much more efficient. Numeircal tests demonstrate the effectiveness of our proposed method.