松辽盆地古龙凹陷嫩江组二、三段层序地层及油气藏分布规律

Sequence stratigraphy and distribution law of oil-gas reservoirs of 2nd and 3rd members of Nenjiang Formation in Gulong Sag, Songliao Basin

通过高分辨率层序地层学研究,在松辽盆地古龙凹陷嫩江组二、三段识别出最大湖泛面、最后湖泛面和沉积作用转换面,识别出高水位体系域和湖盆收缩体系域,划分出3个准层序组11个准层序,建立了高频层序地层格架;指出古龙凹陷油气藏分布受烃源岩成熟度、沉积相带、构造等因素综合控制,凹陷低部位发育岩性透镜体油气藏,周边鼻状构造部位发育上倾尖灭及构造油气藏,总体呈环带状分布,纵向自下而上具有岩性透镜体、上倾尖灭及构造油气藏分布特征。

Based on the theory of high-resolution sequence stratigraphy, maximum lake-flooding surface, ultimate lake-flooding surface, sedimentation transfer surface, highstand systems tract and lake regression systems tract of the second and third members of Nenjiang Formation in Gulong Sag, Songliao Basin have been identified, The 2nd and 3rd members of Neijing Formation has been di- vided into 3 para-sequence sets and 11 para-sequences, and the high-resolution sequence stratigraphic framework has been established. It points out that the distribution of oil-gas reservoirs in Gulong Sag is controlled by the maturity of source rocks, sedimentary facies belts and structure. Lithologic lens oil-gas reservoirs distributed in the lower part of Gulong Sag, and up-dip pinch-out and structural oil-gas reservoirs were developed in structural nose. These oil-gas reservoirs distributes generally in ring-belt. The distribution of oil-gas reservoirs in vertical from down to up is featured with lithologic lens, up-dip pinch out and structural oil-gas reservoirs.