According to the introduction and analysis of relevant data, "crude oil" and "petroleum" are two closely related concepts, and it is really difficult to distinguish them without careful analysis. "Petroleum" is a term put forward as early as 1000 years ago. Shen Kuo, a scholar in the Northern Song Dynasty, has already mentioned "oil" in his masterpiece Meng Qian Bi Tan. Shen Kuo noticed that people in some places use underground oily black liquid for lighting and cooking. Shen Kuo called it "oil" because it was taken from underground rocks.

With regard to the specific substance names of "crude oil" and "petroleum", "crude oil" refers to the black or dark brown viscous oily substance taken out from the stratum without any refining. Besides "crude oil", it can also be called "oil". When crude oil is sent to a refinery for processing and refining, the new substance obtained can still be called "oil" or, more accurately, "petroleum products", but it can't be called "crude oil" or "crude oil products" customarily. For example, we can say "gasoline": "gasoline is a kind of petroleum, which is the fractionation product obtained during the fractionation of petroleum within a certain temperature range." In this sentence, the former "oil" cannot be replaced by "crude oil", and the latter "oil"

It can be replaced by "crude oil", that is, it cannot be expressed as: "gasoline is a kind of" crude oil ",which is a fractionation product obtained in a certain temperature range during the fractionation process of" crude oil ". In addition, LPG can only be called LPG, not crude oil gas. Others, such as kerosene, lubricating oil, naphtha and asphalt, can be called "an oil" or "petroleum products", but they cannot be called "a crude oil" or "crude oil products".

To sum up, the extension of "crude oil" is narrow, which only refers to the "oil" in its original state taken out from the stratum without any processing and refining; The extension of "petroleum" is very wide, and we can call the combustible substances taken out of the stratum "petroleum" before and after processing, just processed petroleum products. According to their characteristics and uses, people give them more accurate names, such as "gasoline", "diesel", "lubricating oil" and "asphalt", so as to distinguish them.