PETROLEUM GENERATION MODEL OF A SULFUR—RICH KEROGEN FROM THE LINNAN SAG, THE BOHAI BAY BASIN

Kerogen from some source rocks in the third and forth members of the Sahejie Formation in the Linnan Sag,the Bohai Bay Basin have been reported to be sulfur-rich.However,there has been little knowledge about the petroleum-generating model of this type of kerogen.In this paper,the kinetics method was applied to investigate petroleum generation kinetics parameters and geological model for a typical sulfur-rich kerogen from the sag.The results have shown that the oil-generating threshold of the kerogen occurs at EasyR_o of 0.53%,the oil-generating peak range from 0.60% to 0.75% and oil-generating death line at 0.85%,corresponding to burial depths of 2 500 m,2 600～3 250 m and 3 850 m,respectively,and its gas-generating threshold is at EasyR_o of 1.05% and main gas generation stage occurs from 1.23%,with a burial depth of 4100m and 4 650 m,respectively.Compared with conventional kerogen petroleum-generating models,this sulfur-rich kerogen is characterized by a narrow oil window and an earlier occurrence of oil-generating peak.This result will provide a guide to the petroleum evaluation and exploration in this area.