Maps and GPS directions to Eni Constanta 1-TOMIS and other ENI locations in Romania. Find your nearest ENI. ENI petrol filling stations in Romania. Eni S.p.A. is an Italian oil and gas company. ENI is present in 79 countries. ENI operates in a large number of fields including contracting, nuclear power, energy, mining, chemicals and plastics, refining/extraction and distribution machinery, hospitality industry and even textile industry and news.