2.5D induced polarization forward modeling using the adaptive finite-element method
Ye Yi-Xin1,2,3, Li Yu-Guo1, Deng Ju-Zhi2, and Li Ze-Lin2
1. Key Lab of Submarine Geosciences and Prospecting Techniques of Ministry of Education, Ocean University of China, Qingdao 266100, China.
2. Fundamental Science on Radioactive Geology and Exploration Technology Laboratory, East China Institute of Technology, Nanchang 330013, China.
3. Hubei Subsurface Multi-scale Imaging Lab (SMIL), China University of Geosciences (Wuhan), Wuhan 430074, China.
Abstract：
The conventional finite-element (FE) method often uses a structured mesh, which is designed according to the user’s experience, and it is not sufficiently accurate and flexible to accommodate complex structures such as dipping interfaces and rough topography. We present an adaptive FE method for 2.5D forward modeling of induced polarization (IP). In the presented method, an unstructured triangulation mesh that allows for local mesh refinement and flexible description of arbitrary model geometries is used. Furthermore, the mesh refinement process is guided by dual error estimate weighting to bias the refinement towards elements that affect the solution at the receiver locations. After the final mesh is generated, the Jacobian matrix is used to obtain the IP response on 2D structure models. We validate the adaptive FE algorithm using a vertical contact model. The validation shows that the elements near the receivers are highly refined and the average relative error of the potentials converges to 0.4 % and 1.2 % for the IP response. This suggests that the numerical solution of the adaptive FE algorithm converges to an accurate solution with the refined mesh. Finally, the accuracy and flexibility of the adaptive FE procedure are also validated using more complex models.
YE Yi-Xin,LI Yu-Guo,DENG Ju-Zhi et al. 2.5D induced polarization forward modeling using the adaptive finite-element method[J]. APPLIED GEOPHYSICS, 2014, 11(4): 500-507.
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2014, Vol. 11 
