松辽盆地生油门限重新厘定及其意义

Oil generation threshold depth of Songliao Basin: Revision and its significance

对松辽盆地滨北地区、主力烃源岩区（齐家－古龙凹陷和三肇凹陷）、主力烃源岩层（白垩系青山口组一段、青二段－青三段）成烃转化率－埋深关系曲线及R0－埋深关系曲线进行了系统分析，重新厘定盆地生油门限深度。结果表明，松辽盆地主力烃源岩的生油门限深度可能为1400～1700m，而不是过去认为的1200m左右。生油门限深度的变化对盆地各地区资源潜力和勘探方向具有不同的影响：对于主力烃源岩区，生油门限变深，将使评价所得生、排烃量减少，但对资源潜力没有明显影响，可能影响对勘探方向和有利目标的评价；对于烃源岩埋藏相对较浅的滨北地区，生油门限变深，勘探潜力、勘探方向、有利目标评价将受到至关重要的影响；对于盆地内抬升剥蚀量较大的东南隆起区，生油门限变浅，约为700m，将明显提升朝阳沟阶地、长春岭背斜和宾县－王府地区的勘探潜力。

A systematic analysis was carried out on the relation curve of hydrocarbon transformation ratio vs. buried depth and that of vitrinite reflectance （Ro） vs. buried depth in Binbei area, major source rock area （Qijia-Gulong Sag and Sanzhao Sag）, and major source rock layer （Cretaceous Qing-1 Member, Qing-2 - Qing-3 Members） in Songliao Basin, to re-determine the oil generation threshold depth of the basin. The oil generation threshold depth of the major source rocks is likely to range from 1 400 m to 1 700 m, rather than 1 200 m in the previous estimation. The change of oil generation threshold has different effects on the resources potential and exploration orientation of various areas： For the major source rock areas, increase of oil generation threshold depth will cause decrease of oil generation and expulsion quantity, with no evident effect on the resources potential of major source rock area, but with certain effect on the exploration orientation and favorable target evaluation. For the Binbei area with shallower buried depth of source rocks, it will have great effect on the exploration potential, exploration orientation and favorable target evaluation. For the southeastern uplift area with great denudation in the basin, the oil generation threshold depth is reduced to about 700 m, which will improve the exploration potential of Chaoyanggou terrace, Changchunling anticline and Binxian-Wangfu area.