Abstract: Unconventional petroleum refers to petroleum resources that were not commercially extractable in the last 70s to 80s by traditional technologies. Tight petroleum includes petroleum in tight sandstone, shale and coal bed in a broad sense, while it is limited to petroleum only in tight sandstone in a narrow sense. Shale oil may coexist or associate with shale gas closely. Since the current exploitable shale oil is relatively light, it is also called the light tight oil (LTO). The oil shale belongs to solid mineral resources, with no oil in it; and its production after carbonization is not crude oil but oil products.

Key words: unconventional petroleum, tight petroleum, shale oil and gas, light tight oil, oil shale