Quantifying Seismic Interpretation and Modeling Uncertainties while Building Salt Caverns

As part of building a new salt cavern gas storage facility within a complex Zechstein salt canopy next to the village of Jemgum (Lower Saxony basin, Germany) a detailed geological site characterization was requested. Key input was a reprocessed anisotropic (TTI) controlled beam 3D prestack depth migration were 5D data regularization has been applied in advance of migration to improve seismic imaging. 3D velocity building was further supported by integration of 3D gravity data. In order to precisely determine the distance between cavern edges and salt interface various different salt models have been created by applying different workflows (manual seismic interpretation, adaptive seismic geobody building, supervised neural network building). Subsequently, instead of purely visual assessment, Hausdorff metrics have been calculated to numerically determine mesh differences of the salt interface. These numerical values have then been draped over the mesh to better visualize and efficiently detect mesh differences. Deployed methods and workflows have a very positive impact on spatial precision. It furthermore accelerates model building considerably.