Application study of 3D seismic survey in engineering investigation

3D seismic reflection method is rarely utilized in the urban engineering investigation. Especially, application on this aspect is nearly vacant in China. In order to investigate the application effect of 3D seismic method under the complex condition of cities, we selected a subsurface reservoir as exploration goal in Shanghai and carried out 3D seismic data acquisition. The cross observation system was used and shot/receiver interval was lm. The fold is 36. We use a hydraulic impact mechanism as hypocenter. The geophone's natural frequency is 28Hz. The raw show gathers show that the surface wave and correlation noise are so strong that the reflection signal is hard to identify. So we use surface wave zone noise suppressing methods and FX correlation noise suppressing technology to wide off the noises. Moreover, surface consistent amplitude compensation, inverse deconvolution, residual static, velocity analysis, stack processing technologies and so on are used and the stack sections are acquired. The results show that the reflection from bedrock is interrupted, due to the boundary of the reservoir, by which the area coverage of the reservoir is nearly determined. However, because the reservoir is buried very shallow and its structure is so complex, other geophysical methods and drilling data are needed to identify its precise position. Our study lays a foundation for the further research.