南襄盆地泌阳凹陷烃源岩成熟度厘定及其意义

摘要

19 source rock samples of lacustrine facies have been collected from the Hetaoyuan Formation in 15 drilling wells in the Biyang Sag of the Nanxiang Basin, and their maturities have been determined by means of fluorescence alteration of multiple macerals (FAMM) technique. The vitrinite reflectance of source rocks from the Hetaoyuan Formation is obviously suppressed, and the suppression corrected value is from 0. 08% to 0. 39% . The level of vitrinite reflectance suppression is relatively higher when source rock quality is better. The maturity of 19 samples has entered oil window (EqVR from 0. 58% to 1. 29% ) instead of 0. 38% -1. 05% from vitrinite reflectance. According to the maturity of source rocks at different depth in 4 wells, paleogeothermal gra-dient is 36-45 ℃ / km, and the depth of threshold for oil generation is 1 800-1 400 m. The correct determina-tion of maturity for the source rocks from the Hetaoyuan Formation provides the basis to evaluate the potential of hydrocarbon reasonably.%　　利用 FAMM 技术对取自南襄盆地泌阳凹陷15口钻井的19件核桃园组湖相烃源岩样品进行了成熟度厘定.结果显示,烃源岩的镜质体反射率(Ro )抑制程度显著,抑制校正值介于0.08%~0.39%,有机质类型越好,镜质体反射率抑制程度越高.19件烃源岩样品的成熟度均已处于生油窗内(等效镜质体反射率值介于0.58%~1.29%),而非镜质体反射率结果所反映的处于0.38%~1.05%.根据4个钻井不同深度段烃源岩的成熟度确定古地温梯度为36~45℃/ km,成烃门限深度为1800~1400 m.核桃园组烃源岩成熟度的正确厘定,为合理评价泌阳凹陷石油资源潜力奠定了基础.