Abstract:

By means of the methods of sonic time difference and Easy%Ro modeling based on vitrinite reflectance，the erosion thickness of Sanduo Formation is reconstructed in Jinhu sag，Subei basin.It is pointed out that the fundamental reason for the "shallow matured" phenomenon in the uplift zones and outer-slope area is due to the particular geological setting of the ancient burial depths which was greater than the present ones (or called degenerative thermal history).As a result of the ancient burial depth larger than the present，and the paleo-temperature gradient larger than the present，source rock in Funing Formation reached its maximum thermal evolution degree at the end of Sanduo Formation sedimentation period.Based on the reconstruction of erosion thickness of Sanduo Formation，the paleo-structure of main carrier beds and hydrocarbon generation status of Funing source rocks in the end period of sedimentation of Sanduo formation are reconstructed，and petroleum migration and accumulation units are divided and evaluated.

Key words: sonic time difference, erosion thickness, burial history, thermal evolution, Jinhu sag