The man dug the tunnel in the oil-rich Novosibirsk region to reach the Omsk-Irkutsk pipeline, which belongs to Transsibneft, a subsidiary of Russian oil pipeline monopoly Transneft.
"A businessman working in the freight traffic industry dug a 60-metre underground tunnel to steal crude oil. He crawled through the tunnel, made a tie-in and connected a hose to it," the spokesman said.
Over a three-month period, the thief stole 30 tonnes of crude, and the pipeline's losses are estimated at 500,000 rubles ($16,200), police said.
The businessman, who faces charges of large-scale theft, later reportedly claimed that his efforts had been unprofitable, as he had spent more money obtaining the crude oil than he had earned from stealing it.
"The man confessed that stealing the crude had turned out to be difficult on a practical level, as the fuel was always overflowing, soiling his clothes," police said.