Abstract: In 2006, the author in this paper used the play assessment method to predict the size, number and undiscovered oil & gas resources of the undiscovered oil and gas fields in 39 units of the Pearl River Mouth Basin, based on 438 undrilled traps and the geological model of each unit. On the basis of giving the major evaluation parameters, results, and basic conclusions, the author focuses on comparing the exploration results in main exploration areas from 2006 to 2009 with the forecast accomplished four years ago, which are proved the same in general. The play analysis method is proved to be necessary and feasible after case study of above-mentioned verification. It is believed that the play assessment should be the mainline in geology study of oil companies. It is the core of geological evaluation to predict the size and number of undiscovered oil & gas fields in a specific unit, to predict the probability that at least one oil and gas field should be found in the units that no commercial discoveries have been made, and to verify the predictionhaving been made as the exploration progresses. Finally the author discusses the concerned problems in the Pearl RiverMouth Basin resources assessment such as the data updating of undrilled traps, the oil-trend or gas-trend in southern margin of Baiyun Sag, the deeply study of main-control elements on reservoir forming, and the reserve growth as well as its meaning.

Key words: Pearl River Mouth Basin, play assessment, verification by exploration