SimPEG.EM Casing Example based on the Schenkel and Morrison Casing Model

SimPEG.EM Casing Example based on the Schenkel and Morrison Casing ModelLindsey J. [e-mail] 29, 2016OverviewHere we create and run a FDEM forward simulation to calculate the vertical current inside a steel-cased. The model is based on the Schenkel and Morrison Casing Model, and the results are used in a 2016 SEG abstract by Yang et al. This example uses the open source simulation and parameter estimation package SimPEG (http://simpeg.xyz).- Schenkel, C.J., and H.F. Morrison, 1990, Effects of well casing on potential field measurements using downhole current sources: Geophysical prospecting, 38, 663-686.The model consists of:- Air: Conductivity 1e-8 S/m, above z = 0- Background: conductivity 1e-2 S/m, below z = 0- Casing: conductivity 1e6 S/m - 300m long - radius of 0.1m - thickness of 6e-3mInside the casing, we take the same conductivity as the background.We are using an EM code to simulate DC, so we use frequency low enough that the skin depth inside the casing is longer than the casing length (f = 1e-6 Hz). The plot produced is of the current inside the casing.These results are shown in the SEG abstract by Yang et al., 2016: 3D DCresistivity modeling of steel casing for reservoir monitoring using equivalentresistor network. The solver used to produce these results and achieve the CPUtime of ~30s is Mumps, which was connected using pymatsolver(https://github.com/rowanc1/pymatsolver)Instructions:- python is required to run the example- dependencies can be installed using pip: `pip install -r requirements.txt`- to run the example: `python EM_Schenkel_Morrison_Casing.py`