Abstract:

Comparative analyses of petrology,thermodynamic characteristics and components of inclusions in the 2^nd member of Xujiahe Formation in northwestern Sichuan show that the inclusions had been formed in 4 different stages,i.e.in Late Triassic to Shaximiao age,middle-late Late Jurassic to early Early Cretaceous,Early Cretaceous to pre-Himalayan, and post-Himalayan, respectively,which represent 4 hydrocarbon charging processes.Analysis of the fluid inclusions can reveal paleo-elevation-density and-pressure when the inclusions were entrapped.These data can be used to calculate the fossil fluid potential.This method has been used to calculate the fossil fluid field of the 2 ndmember of Xujiahe Formation in northwestern Sichuan.The results show that regional fluid field obviously has gone through an evolution process of variation adjustment revariation-readjustment.

Key words: fluid potential, fluid inclusion, 2^nd member of Xujiahe Formation, northwestern Sichuan