渤海湾盆地东营凹陷孔店组烃源岩特征研究

沙三下和沙四上是东营凹陷的2套优质烃源岩。目前认为东营凹陷南斜坡原油主要属于“沙四型”,而对于东营凹陷孔店组的生烃潜力一直存在着争论。油源对比结果表明,孔店组烃源岩以较高的伽马蜡烷区别于沙三型烃源岩,又以较高的三升藿烷和C₂₉甾烷S构型区别于沙四型烃源岩;南斜坡孔店组及其以下的深层原油与孔店组烃源岩具有亲缘关系。虽然目前发现的孔店组烃源岩有机质含量较低、类型差、成熟度较高,综合评价较差,但是生物标志化合物显示,向沉积中心其有机质有优化的趋势。因此推测在沉积中心发育更优质的孔店组烃源岩,其生烃潜力不容忽视。

CHARACTERISTICS OF SOURCE ROCK OF THE KONGDIAN FORMATION IN SOUTH SLOPE OF THE DONGYING SAG, THE BOHAIWAN BASIN

The source rocks of lower Es~3 and upper Es~4 are high quality source rock in the Dongying Sag of the Bohaiwan Basin.It was considered that the crude oil on south slope of the Dongying Sag mainly came from Es~4 source rock;while it was argued that whether Ek~2 can generate hydrocarbon.The correlation between oil and source rock shows that Ek~2 source rock differs from Es~3 source rock with higher gammacerane and differs from Es~4 source rock with higher trishomohopane and S configuration of C_(29)sterane.There is consanguinity between crude oil in deeper layers and Ek~2 source rock.Although Ek~2 source rock was found belongs to bad source rock with lower organic carbon,poorer type of kerogen and higher maturity,it optimizes toward the sag center based on biomarkers.So it is presumed that there would be good source rock of Ek~2 in its sedimentary center,and the genetic potential of Ek~2 would be large.