The first oil-producing regions in the human history were located near Baku. Until the beginning of the 20th century, the Balachany-Sabuncu-Ramany region produced more than 60% of Baku's oil. This oil sources are largely exploited and contain yet only heavy extractable fractions of crude oil. Experiments with oil samples from this oil fields show, that irradiation with microwaves under addition of magnetite catalysts leads to a reduction of petroleum viscosity. It seems to be a new attempt for intensive extraction of petroleum.