This article describes the opportunities of differential thermomagnetic analysis of epigenetic variations of iron compounds under the hydrocarbon effects' study. The object of research is the rock of subsoil layer on the territory of northern site of Saraylinskoye oil-field. Ninety-three samples were examined. Zoning of the territory's part of research under the types of differential thermomagnetic analysis's curved lines was made. Territory's outline, for which is typical the presence of pyrite and siderite in the samples, spatially control the oil deposits in the Tula terrigenous rocks of the Lower Carboniferous and Timanskian terrigenous rocks of the Upper Devonian
