<p>Oil and natural gas production in China has become a key governance target of volatile organic compounds (VOCs). To develop countermeasures, direct emission data obtaining from industrial sources is crucial, but so far has been lacking. In this work, an industrial case in Junggar Basin was studied. Through direct sampling and data analysis, emission characteristics at the source level were revealed, as well as inventory and environmental risks. Emission sources studied here included storage tanks, accident emissions, loading operations, wastewater collection and treatment system, process vents, and equipment leaks. Among them, storage tanks were found most important, as they resulted in 90% of emitted VOCs, 89.2% of the OFP, and 81.6% of the SOA yield. 74 VOC species were discovered, among which alkanes contributed the most. Half of alkanes in this case were long-chain alkanes (C₇ ~ C₁₂). Instead of focusing on surrounding air, this case directly targeted various emission sources along the production chain. Octane and decane were top 2 species rather than propane and ethane, in contrast to previous studies. In addition to alkanes, oxygenated VOCs and aromatics should also be considered when choose treatment technologies, in terms of environment risks. VOCs reduction recommendations are provided for each emission source.</p>