Ukraine's double-barreled drone strikes on Russian oil refineries and Black Sea ports are simultaneously disrupting domestic fuel supplies and blocking crude exports. In the four weeks through August 23, Russia shipped 3.46 million barrels a day, the lowest level in four months, according to tanker-movement data compiled by Bloomberg.

Previously, attacks on refineries had left more crude available for export, causing shipments to rise. However, that trend is now reversing after drone hits on oil tankers cut shipments from the Black Sea. The coordinated campaign prevents Moscow from diverting excess crude into overseas markets, squeezing both domestic refining capacity and export revenue streams.