Inverse Gaussian-beam common-refl ectionpoint-stack imaging in crosswell seismic tomography*
Wei Zheng Rong, Yang Fei-Long, Liu Bao-Hua, and Pei Yan-Liang
1 College of the Geological Engineering and Geomatics, Chang’an University, Xi’an, 710065 China.
2 College of the Geoscience and Engineering, Xi’an Shiyou University Xi’an, 710064 China.
3 National Deep See Center, Qingdao, 266273, China.
4 The First Institute of Oceanography, SOA, Qingdao, 266061 China.
Abstract：
To solve problems in small-scale and complex structural traps, the inverse Gaussian-beam stack-imaging method is commonly used to process crosswell seismic wave reflection data. Owing to limited coverage, the imaging quality of conventional ray-based crosswell seismic stack imaging is poor in complex areas; moreover, the imaging range is small and with sever interference because of the arc phenomenon in seismic migration. Thus, we propose the inverse Gaussian-beam stack imaging, in which Gaussian weight functions of rays contributing to the geophones energy are calculated and used to decompose the seismic wavefield. This effectively enlarges the coverage of the reflection points and improves the transverse resolution. Compared with the traditional VSP–CDP stack imaging, the proposed methods extends the imaging range, yields higher horizontal resolution, and is more adaptable to complex geological structures. The method is applied to model a complex structure in the K-area. The results suggest that the wave group of the target layer is clearer, the resolution is higher, and the main frequency of the crosswell seismic section is higher than that in surface seismic exploration The effectiveness and robustness of the method are verifi ed by theoretical model and practical data.
2019, Vol. 16 
