Research on oil exploration seismic Rayleigh wave imaging based on multi-channel analysis of surface waves and genetic-damped least squares joint inversion

Rayleigh waves in oil exploration seismic records usually have strong energy and are considered as noise, but Rayleigh waves also carry information about subsurface. In this paper, we process Rayleigh waves from a set of oil seismic data to detect underground structures of shear-wave velocity (vs) using multi-channel analysis of surface waves (MASW). Fundamental mode and higher order mode dispersion curves of the Rayleigh wave were automatically extracted by a modified phase shift method. We then use the genetic and damped least squares (DLS) joint inversion algorithm to inverse the dispersion curves and obtain a one-dimensional (1D) vs structure under each shot gather. Finally, all 1D vs structures were combined to create a 3.2 km long two-dimensional (2D) section, revealing a stratum structure down to 80 m depth. The results show that MASW technology successfully improves the use of oil seismic data, the automatic dispersion extraction method based on modified phase shift improves the efficiency of data processing, and the joint inversion algorithm reduces the dependence of the Rayleigh wave dispersion inversion on initial model.