An integrated long-wavelength static correction method for complex near-surface area
Wang Zhigang1,2,3, Liu Zhiwei1,2, Wang Yanchun1, Pan Yinhai4, Xu Wenli5
1. Geodetection and Information Technology Institute, China University of Geosciences (Beijing), Beijing 100083, China; 2. Key Laboratory of Earth Prospecting and Information Technology, China University of Geosciences (Beijing), Beijing 100083, China; 3. Beijing Tiecheng Construction Supervision Co. Limited, Beijing 100855, China; 4. Petroleum Geophysical Exploration School, BGP Inc., CNPC, Zhuozhou, Hebei 072751, China; 5. Faculty of Earth Resources, China University of Geosciences (Wuhan), Wuhan, Hubei 430074, China
Abstract：Long-wavelength static corrections in complex near-surface area are always one of the difficulties in seismic data processing. A single statics method cannot presently obtain high-quality gathers because of data sparse coverage or/and unmet hypothesis. In complex near-surface terrains, to obtain accurate weathering velocity and thickness, and refraction velocity is severe nonlinear problem. In this paper, we propose an approach to solve long-wavelength static corrections by linearization of nonlinear problem and model replacement. Both LVL data and seismic data contain rich long-wavelength information, therefore two types of data should be comprehensively taken in account for solving the problem. We first build initial velocity field with the constrain of LVL data and first breaks, then obtain near-surface model by invert velocity with tomostatics, and finally use first break traveltime fitting on common shot gathers, common receiver gathers, and common offset gathers. Applications in complex near-surface area, western China show the validity of this integrated method.
