Abstract: The petroleum reservoir formation system is an approach for further subdivision of petroleum evaluation units proposed based on petroleum system study. It adheres to the principle of petroleum system, and possesses the regulations of the system. It can be as a geologic unit for petroleum evaluation. The analytical hierarchy process belongs to a new branch of the system study, and is in accordance with the properties of sets, correlation, hierarchy and non-simple addition. So it is also a decision-making approach of the qualitative integrated with quantitative analysis. By applying the analytical hierarchy process to quantitative evaluation of Upper Triassic in the middle area of Sichuan basin,good results are obtained.

Key words: Sichuan basin, quantitative, evaluation, reservoir-formed system, hierarchy analysis