Numerical modelling and propagation law of seismic wave field in loess plateau of Ordos basin
HAN Linghe1,2,3, HU Ziduo2,3, DI Bangrang1, XU Zhonghua2,3, LIU Wei2,3, LI Xiang2,3
1. National Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum (Beijing), Beijing 102249, China; 2. Research Institute of Petroleum Exploration & Development-Northwest, PetroChina, Lanzhou, Gansu 730020, China; 3. CNPC Key Laboratory of Reservoir Description, Lanzhou, Gansu 730020, China
Abstract：In order to study the propagation law of seismic waves and the generation mechanism of noise in the loess plateau,this paper establishes 3D realistic models （velocity and quality factor Q） of the loess plateau in Ordos basin according to actual surface elevation and velocity structure of the Qingcheng North 3D work area. Then under the condition of undulating land surface,3D numerical modelling using the coordinate transformation method is accomplished based on a viscoacoustic wave equation with explicitly expressed quality factor. This method can simulate the strong energy noise near the offset caused by complex near-surface and strong attenuation effects,and obtain simulation results similar to the real seismic data. Through wave field analysis of the numerical modelling results of the models with different complexity,this paper gradually clarifies the generation mechanism of near-offset strong energy noise,multiple reflection and multiple refraction. Finally,this paper analyzes the differences in wave field characteristics at different locations （plateau,ridge,hillside,ditch） and at different source depth in the loess plateau area based on the numerical modelling and actual data. Analysis shows that when excited in the ditch,the near-offset strong energy noise is weaker,and the data quality is relatively good； As the source depth increases,the high-frequency component of the signal gradually increases； For real seismic data acquiring in the loess plateau,it is necessary to avoid excitation in the dry loess layer and try to excite in the clay layer or deeper layer. The conclusion of wave field analysis has positive guiding significance for real data acquiring and processing in the loess plateau.
韩令贺, 胡自多, 狄帮让, 徐中华, 刘威, 李翔. 鄂尔多斯盆地黄土塬区地震波场数值模拟及传播规律[J]. 石油地球物理勘探, 2024, 59(3): 504-513.
HAN Linghe, HU Ziduo, DI Bangrang, XU Zhonghua, LIU Wei, LI Xiang. Numerical modelling and propagation law of seismic wave field in loess plateau of Ordos basin. Oil Geophysical Prospecting, 2024, 59(3): 504-513.
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