Petroleum is often referred to as the blood of industry; it is a vital strategic mineral resource that underpins the development of the modern energy sector, the petrochemical industry, and industrial manufacturing. The following section provides an overview—from a standard industry perspective—of the common classification methods for petroleum and the characteristics of its various applications.
Based on its physical state upon extraction, petroleum is broadly categorized into three main types: crude oil, natural gas, and condensate. Crude oil is a viscous liquid mineral extracted from underground reservoirs that has not yet undergone refining or processing; it constitutes the primary raw material form for the petroleum industry. Natural gas is frequently found in association with crude oil, existing within geological formations in a gaseous state. Condensate possesses dual gas-liquid characteristics: it exists as a gas underground but condenses into a liquid upon extraction to the surface and subsequent cooling; it is considered a high-quality, light-grade petroleum resource.
Based on density and specific gravity, petroleum can be classified into light crude oil, medium crude oil, and heavy crude oil. Light crude oil features low viscosity and minimal impurity content, making it easier to refine and yielding higher proportions of premium fuels such as gasoline and aviation kerosene. Heavy crude oil, conversely, contains higher levels of resins and asphaltenes; due to its high viscosity and processing complexity, it is primarily utilized in the production of industrial heavy fuel oil, road asphalt, and similar products.
Based on sulfur content, petroleum is further subdivided into low-sulfur crude oil, sulfur-bearing crude oil, and high-sulfur crude oil. Low-sulfur crude oil is of superior quality, causes minimal corrosion to equipment, and possesses distinct environmental advantages. High-sulfur crude oil, however, necessitates specialized desulfurization processes; consequently, it represents a critical focal point for process control within refining enterprises, as well as a key category for environmental monitoring and regulation.
From the perspective of processing applications, petroleum can be broadly classified into two categories: fuel-grade and chemical feedstock-grade. Fuel-grade crude oil undergoes refining to produce products such as gasoline, diesel, kerosene, and industrial heavy fuel oil, which are widely utilized in transportation, heating systems, and industrial combustion processes. Chemical feedstock-grade crude oil serves as the raw material for manufacturing a diverse array of chemical products—including plastics, synthetic rubber, synthetic fibers, and coatings—thereby becoming deeply integrated into various aspects of both daily life and industrial production.
A clear understanding of these standard petroleum classifications is essential for comprehending the distinctions in fuel quality, the variations in refining processes, and the underlying logic behind environmental management and regulatory controls within the industry. Against the backdrop of Dual Carbon development, the refined sorting, clean processing, and efficient resource utilization of petroleum have emerged as the mainstream trends in the industry. By leveraging a standardized classification system, it is possible to further enhance energy utilization efficiency and facilitate the green, low-carbon, and high-quality development of the energy sector.