Morphostructural modeling of the block structure of a part of the Scandinavian crystalline shield has shown that the ring structure of the Siljan Ring impact crater is located in the center of a morphostructural node, a ring structure with a diameter of 300 km, marking a large disjunctive tectonic knot. The crater area consists of a central block, which is a granite massif, and of a surrounding mobile morphostructural boundary forming a wide small-block ring depression zone, where oil and gas shows have been revealed within the crater. This zone is regarded as the most promising one for search for migration channels and atypical shows of hydrocarbons.