Abstract: With the increasing of exploration maturity,the focus of exploration target evaluation has gradually shifted from basins to plays and traps.As the major targets to hydrocarbon discovery,preliminary exploratory plays are the main targets to achieve exploration benefit.However,evaluation of preliminary exploration target is very challenging due to the low exploration maturity and multiple evaluation parameters which are difficult to quantify.Based on the principles of exploration risk analysis,this paper established the model of probability of hydrocarbon discovery-strategic value of resources for evaluation of preliminary exploratory plays,and provided relevant assessment parameters,assignment criteria,computational formula and results classification methods,making it possible to evaluate preliminary exploration target on an unified platform.Five preliminary exploration plays in the Sichuan Basin,such as Tongnanba,Exi-Yudong,Nanjiang,lower combination of southeast Sichuan and Zhixinchang-Longbaoliang,are selected and evaluated with this model.

Key words: evaluation model, strategic value of resources, probability of discovery, play evaluation, preliminary exploratory play