1. 中国石油大学（北京）油气资源与探测国家重点实验室，北京 102249；
2. 中国石油大学（北京）CNPC物探重点实验室, 北京 102249；
3. Edinburgh Anisotropy Project, British Geological Survey, Edinburgh EH9 3LA, UK
Converted-wave diodic moveout and application in the land gas cloud area
Zhang Si-Hai1,2 , Li Xiang-Yang2,3, and Dai Heng-Chang3
1. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249 China.
2. CNPC Key Laboratory of Geophysical Prospecting, China University of Petroleum, Beijing 102249 China.
3. Edinburgh Anisotropy Project , British Geophysical Survey, Edinburgh EH9 3LA, U.K.
Abstract：
PS converted-waves (C-waves) have been commonly used to image through gas clouds but the C-wave imaging may also be degraded by the diodic effect introduced by the gas cloud. It may be compensated for using a velocity perturbation method which decouples the diodic moveout into two parts: the base velocity and the velocity perturbation. Gas clouds are widely distributed in the Sanhu area in the Qaidam basin of northwest China which is rich in natural gas. A land 2D3C seismic dataset is analyzed from the Sanhu area and signifi cant diodic effects are observed in the data which harm the C-wave imaging. The diodic correction is applied to this data and the resultant C-wave imaging and the details of the reservoir structure are significantly improved. The diodic moveout plays an important role in working out the residual shear wave statics and the association of diodic correction and shear wave residual statics computation is a key step of C-wave high fi delity imaging in the gas cloud area. Finally, the new process workfl ow with diodic moveout is given.
ZHANG Si-Hai,LI Xiang-Yang,DAI Heng-Chang. Converted-wave diodic moveout and application in the land gas cloud area[J]. APPLIED GEOPHYSICS, 2011, 8(3): 171-180.
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2011, Vol. 8 
