伊通盆地岔路河断陷始新统岩性圈闭研究

Study of Eocene lithologic traps in Chaluhe fault depression of Yitong Basin

伊通盆地岔路河断陷是一双断式内陆断陷,其内,始新统发育6个三级层序地层单元。通过对各层序中不同体系域单元的沉积特征分析认为,该区始新统水进体系域和高水位体系域的暗色泥岩,与低水位体系域的低水位楔、低水位扇及高水位体系域的大型三角洲等湖相砂体呈横向上相变过渡,纵向上交互,构成了良好的生储盖组合；在新安堡凹陷內的低水位体系域申形成了透镜状岩性圈闭,在新安堡凹陷及万昌构造带周缘的低水位体系域中形成了岩性或复合型岩性圈闭,为该区岩性油气藏的形成创造了条件。

Chaluhe fault depression is a grahen inland one, where there are 6 third class sequence stratigraphic units. By analyzing the depositional features of the different system tract of every sequence, the authors consider that the dark mudstone of transgressive system tract and highstand system tract is characterized by phase presenting transition laterally and alternation vertically, by comparison with the lowstand system wedge, fan of the [owstand system tract, and the large^scale delta- limnetic facies ore mass of highstand system tract. The mudstone formed a favorable source-reservoir-caprock associateion, lensing lithologic traps in the lowstand system tract in Xin＇anbao sag, and lithologic or complex lithologic traps in the lowstand system tract around the Xin＇anbao sag and Wanchang tectogene. It created favorable condition for forming the lithologic oil reservoir in the region.