This article examines the mechanisms of hydrocarbon losses to the atmosphere during oil field processing, including evaporative, fugitive, and process-related emissions. A detailed classification of emission sources is provided along with a physicochemical description of vaporization and leakage processes. Regulatory frameworks are reviewed. Special attention is paid to modern engineering, technological, and diagnostic approaches to emission reduction, such as vapor recovery units (VRUs), floating roof tanks, pressure equalization systems, and digital leak monitoring technologies. It is shown that an integrated approach can reduce total hydrocarbon emissions by 60–80%, improve environmental performance, and enhance resource efficiency in oil production.