松辽盆地营城组优质烃源岩地质特征及勘探意义

为充分认识松辽盆地营城组烃源岩的发育特征，对已钻探井岩心进行地球化学热解和分子有机地球化学研究，在松辽盆地营城组发现了高丰度的Ⅱ型优质成熟烃源岩；结合层序地层及地球物理技术手段，明确了优质烃源岩在层序地层格架内和平面的分布规律。研究结果表明：研究区烃源岩TOC值平均达到2.46%，有机质类型以Ⅱ型为主，有机质中含有大量的水生藻类，镜质体反射率R_o为0.8%~1.0%，处于生烃高峰期。断-坳转换末期相对平稳的构造背景是烃源岩发育的有利环境，生物标志化合物中低Pr/Ph（姥鲛烷与植烷比值）证实具备有机质保存的有利环境。优质烃源岩在垂向上主要发育在SQ1层序和SQ2层序的湖侵体系域和高位体系域，SQ1层序优质烃源岩的发育厚度一般为20~80 m，SQ2层序优质烃源岩的发育厚度一般为10~30 m。油源对比证明双城地区优质烃源岩直接为油藏供烃，双城地区优质烃源岩的发现对于松辽盆地其他断陷的石油勘探也具有重大意义。

Geological characteristics and exploration significance of high-quality source rocks in Yingcheng Formation,Songliao Basin

In order to comprehensively and effectively recognize source rocks in Yingcheng Formation of Shuangcheng area in Songliao Basin, the geochemical pyrolysis and molecular organic geochemistry characteristics of drilled core are analyzed, high-abundance mature source rocks have been found for the first time. Combining sequence stratigraphy and geophysical techniques, the distribution law of high-quality source rocks is determined. It was recognized that the average total organic carbon (TOC)content is 2.46%, the organic matter is mainly Ⅱ type, there are a plenty of aquatic algae in organic matter, and the vitrinite reflectance (R_o)is in a range of 0.8% -1.0%, so the source rocks are in the peak hydrocarbon-generating stage. A relatively stable tectonic background of fault depression conversion period is a favorable environment for source rocks deposition, low Pr/Ph ratio of nalkane proved favorable environment for the preservation of organic matter. The high-quality source rocks mainly developed in the transgressive system tract and highstand system tract of sequence SQ1 and sequence SQ2, the thickness of high-quality source rocks in SQ1 is generally 20-80 m, while the thickness of high-quality source rocks in SQ2 is generally 10-30 m. The oil source correlation shows that the high-quality source rocks in Shuangcheng area are the direct hydrocarbon source for the reservoir, and the discovery of high-quality source rocks in Shuangcheng area provides reference for other peripheral fault depression exploration.