3-D Gravity Anomaly Inversion for Imaging Salt Structures, With Application to Vinton Salt Dome, Gulf of Mexico

Salt domes are favorable geological structures associated with hydrocarbon reservoirs and critical mineral resources. Currently, imaging salt diapir subsurface structures have received widespread attention. The gravity method has been widely used to interpret salt structures due to the significant density contrast between salts and surrounding sediments. However, complex mass sources at different depths challenge the interpretation of the gravity data over salt domes. In this study, we put forward the mixed L1- and L2-norm regularized inversion of the gravity data observed on the surface to image the 3-D subsurface structure of salt domes. The synthetic tests demonstrate that the mixed-norm regularization inversion of gravity data can effectively recover subsurface complex density anomalies similar to salt dome structures. The practical application in the Vinton Salt Dome reveals a shallow high-density caprock and a deep low-density salt core beneath Vinton Dome, greatly enriching the underground structure information of the study area. It demonstrates that the mixed-norm regularized inversion is a valuable interpretation technique for detecting and delineating salt structures.