Abstract: With the development of international oil exploration of SINOPC abroad, some technological specifications relevant to oil and gas exploration need to be in line with international standards. Among of this, it gets more urgent and necessary to establish reserves specifications. In recent years, Chinese companies have required that reserve estimation be implemented for all foreign-related oil fields as per SPE. Therefore, understanding and extending SPE reserves specifications is an important task in oil and gas explorations nowadays. Through analysis and research on documents related to SPE, this paper gives a detailed description to the concept relevant to oil reserves, classifications and applications, illustrates the applied conditions for SPE reserves classifications with some examples, and clarifies the reserves classifications and principles for different reservoirs based on SPE specifications

Key words: oil resources, reserve classifications, prove, probability, possibility