Modeling electromagnetics on cylindrical meshes with applications to steel-cased wells

Table 1:Simulation details for the results shown in Figure 4. Note that the discretizations in the Commer FE and FD codes use one element or one cell across the width of the casing, as does the UBC code. The SimPEG simulation uses 4 cells across the width of the casing. For the time-stepping, each chance in step length requires a matrix factorization. Values for the Commer FE and FD solutions are from Commer et al. (2015)Um et al. (2015).

MeshTimesteppingCompute ResourcesCompute Time
Commer FE8 421 559 tetrahedral elements

893 time steps

9 factorizations

single core

Intel Xeon X5550 (2.67 GHz)

63 hours
Commer FD2 182 528 cells

Δt=3×1010\Delta t = 3 \times 10^{-10} s

120 598 277 time-steps

512 cores

Intel Xeon (2.33 GHz)

23.2 hours
UBC OcTree5 011 924 cell

154 time steps

10 factorizations

single core

Intel Xeon X5660 (2.80 GHz)

57 minutes
SimPEG314 272 cells

187 time-steps

7 factorizations

single core

Intel Xeon X5660 (2.80GHz)

14 minutes
References
  1. Commer, M., Hoversten, G. M., & Um, E. S. (2015). Transient-electromagnetic finite-difference time-domain earth modeling over steel infrastructure. Geophysics, 80(2), E147–E162. 10.1190/geo2014-0324.1
  2. Um, E. S., Commer, M., Newman, G. A., & Hoversten, G. M. (2015). Finite element modelling of transient electromagnetic fields near steel-cased wells. Geophysical Journal International, 202(2), 901–913. 10.1093/gji/ggv193