A New Coarse-to-fine 3-D Magnetotelluric Inversion Method - Application to Field Data for Hydrocarbon Exploration

摘要

Full three-dimensional (3-D) inversion of magnetotelluric (MT) tensor has a great potential for the characterisation of complex geological structures at different scales. We developed a simple and robust 3D MT data inversion method based on the coarse-to-fine parameterisation that was used to provide a detailed geological image of sedimentary basins hidden by thick basaltic cover. For the purpose of petroleum exploration, 3D MT surveys have been recently completed for the understanding of the regional geometry of basins in a volcanic province and continental rift. We present the two examples of Isle of Skye (Scotland) and Omo Basin (Ethiopia) as case studies for 3D MT imaging assessment. For each case, the resolution of the 3-D MT model obtained after full tensor inversion was sufficient to constrain an interpretation of the structural and tectonic history of the basin, and, in Omo Basin, a preliminary assessment of its hydrocarbon potential.