|Title||Marine CSEM of the Scarborough gas field, Part 2: 2D inversion|
|Publication Type||Journal Article|
|Year of Publication||2015|
|Authors||Myer D., Key K, Constable S|
|Type of Article||Article|
We explored the application of 2D inversion of marine controlled-source electromagnetic and marine magnetotelluric data to image an ambiguous target. The Scarborough gas reservoir off the west coast of Australia lies in close repose to a layer in the overburden of similar resistivity-thickness product and also is not far above the resistive basement, making it a difficult electric target. We found that the standard 2D smooth-inversion method yielded models that were unable to resolve this ambiguous structural configuration. We solved this problem by developing a two-step workflow, in which we first invert for a coarse background resistivity model (e.g., anisotropic layers), then invert for the minimum deviation from this background using a much finer model discretization. The main purpose of our two-stage workflow is to inject the knowledge into the inversion that the subsurface is composed of self-similar geologic domains. Though the resulting models did not resolve fine-scale structural details, they might still be used to map the overall extent and bulk qualities of a target in an otherwise confounding setting.