Oil generation threshold(OGT)of the Funing Formation(Ef

Eocene series)in Gaoyou depression of Subei Basin is one of the most important research subjects which arouse reseachers' wide interests.In this study

a suit of samples collected from the same source bed(Ef

4

)but buried at different depths due to the staircase faults are investigated.Based upon the comprehensive studies of various organic geochemistry indices

such as vitrinite reflectance(R°%)

odd-even predominance(OEP)of n-alkanes

centents of sterane and terpaneand their configuration parameters(e.g.C

29

-((20S)/(20S+20R))-5α(H)

14α(H)

17α(H)-sterane

C

29

-moretane/C

29

-hopane ratio

C

31

-((22S)/(22S+22R))-17α(H)

21β(H)-hopane)and the like.The OGT of the Funing Formation has been determined at the depth of ca 2

750m referring to the judging criteria of OGT at home and abroad.In terms of the result

it has been suggested that the Funing Formation in this area only buried at the depth of 2

750m or more is the real source rock of petroleum.Thus provide a prospective evaluation for this oil-bearing basin with effective parameter.