Local geoelectrical inhomogeneities (abnormally conductive embedded bodies) can be mapped using sheet and tomographic areal observation systems within the limits of the 3D frequency-geometrical technology. The overlap sheet-mapping system is considered in detail. An original algorithm is proposed for estimation of the mean inhomogeneity parameter from data of tomographic surveys within a study tomographic square. The two observation systems were experimentally applied on a test ground within a stockwork zone in Zapolie, Orenburg Region, and the practical results are analyzed. With mathematical modeling, we studied the potential of the two survey systems, used within the 3D frequency-geometrical technology, for localization of embedded bodies. The studies allowed us to develop recommendations for achieving higher resolution of observations when using the sheet-mapping system.