Abstract: Based on the principles of petroleum accumulation system,this paper systematically summarizes and perfects the traditional techniques of petroleum resource assessment,and expounds the connotation of resource evaluation under a petroleum accumulation system.On the basis of a deep understanding of the controlling factors of petroleum accumulation and the principles of statistical models,we defined the key objectives of resource assessment at various exploration stages,categorized and standardized the most popular mainstream approaches used in the industry and academia,as well as me-thods evolved during the development of PetroV(a petroleum resource evaluation system of Sinopec),and proposed a methodology framework for resource assessment of a petroleum accumulation system.The categorized five methodology series include 1)probabilistic inference or analogue approaches for frontier targets,2)Monte Carlo approaches for conceptual plays,3)statistical methods for established plays in early exploration stage,4)probabilistic reasoning models for targets in mature plays and 5)discovery process and spatial statistical models in well explored regions. We elaborate the objectives of assessment and the suitability of statistical methods under a variety of exploration scenarios through real examples.In practice,the proposed assessment framework can effectively reduce the sensitivity on parameter selections and the impact due to differences in the geological models on output,thus enhancing applicability of the statistical methods.In addition,the proposed framework may also provide useful information for direction on future methodology development.

Key words: geological model, statistic model, resource assessment, petroleum accumulation theory