Acoustic reflection well logging modeling using the frequency-domain finite-element method with a hybrid PML
Wang Bing1, Kuo Zhang2, Guo Tao3, He Liu1, and Zhang Xiao-Liang4
1. State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing 102249, China.
2. China Center for Information Industry Development, Beijing CCID Publishing & Media Co., Ltd., Beijing 100048, China.
3. Department of Petroleum Geoscience, Khalifa University, Abu Dhabi, United Arab Emirates 2533.
4. Well Logging Company, Western Drilling Engineering Corporation, CNPC, Karamay, Xinjiang 834000, China.
Abstract：
In this paper, we propose a hybrid PML (H-PML) combining the normal absorption factor of convolutional PML (C-PML) with tangential absorption factor of Mutiaxial PML (M-PML). The H-PML boundary conditions can better suppress the numerical instability in some extreme models. and the computational speed of finite-element method and the dynamic range are greatly increased using this HPML. We use the finite-element method with a hybrid PML to model the acoustic reflection of the interface when wireline and well logging while drilling (LWD), in a formation with a reflector outside the borehole. The simulation results suggests that the PS- and SP- reflected waves arrive at the same time when the inclination between the well and the outer interface is zero, and the difference in arrival times increases with increasing dip angle. When there are fractures outside the well, the reflection signal is clearer in the subsequent reflection waves and may be used to identify the fractured zone. The difference between the dominant wavelength and the model scale shows that LWD reflection logging data are of higher resolution and quality than wireline acoustic reflection logging.
. Acoustic reflection well logging modeling using the frequency-domain finite-element method with a hybrid PML[J]. APPLIED GEOPHYSICS, 2018, 15(1): 35-45.
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2018, Vol. 15 
