Rothschild interest in oil dates back to the 1880s when the French bank acquired a refinery at Fiume on the Adriatic and then developed interests in the newly opened oil fields on the Black Sea. Their interests grew until by 1900 they were major operators in the production and marketing of Russian oil, then the largest sector in the world, [before exiting the business in 1912. . . ]
The first Russian oil refineries had been built in 1823 in the north of the Caucasus and around 1830 in Baku. In this region, there were 136 oilwells in 1850 and more than 400 by 1872.
In 1874, Robert Nobel, a Swede, bought a refinery and land in Baku, and it was Nobel who began the first large-scale operations, introducing into Russia tanker-wagons and the first oil tankers (on the Caspian Sea) in 1878. By 1880, Nobel dominated the Russian market and in the following years sought opportunities to extend sales beyond Russia. In 1883, he founded (with the assistance of Deutsche Bank), the Deutsche-russische Naphta-import-Gesellschaft.
By 1900, Russian oil production in effect passed into passed into control of Nobel and Rothschild.
https://guide-to-the-archive.rothschildarchive.org/the-paris-banking-house/depts/french-oil-business
Was Stalin's Father a Rothschild Banker?
https://was-stalin-a-rothschild.blogspot.com/2011/08/rothschilds-and-nobels_22.html