By Ron Bousso LONDON (Reuters) – Top Western oil producers could experience a hit to revenue if disruptions at a Russian Black Sea port curtail output from Kazakhstan’s giant oilfields, highlighting the growing global supply risk after Moscow’s invasion of Ukraine. Chevron, Exxon Mobil, Shell, TotalEnergies and Italy’s Eni are among international companies with stakes in Kazakhstan’s oilfields. Most of the central Asian country’s crude is exported via the Caspian Pipeline Consortium (CPC) pipeline to the port of Novorossiisk, supplying around 1.2% of global oil demand. The port’s operator shut…