辽河东部凹陷古近系层序地层格架及成因分析

本文以地震剖面、测井／录井资料为基础,运用Cross提出的以基准面为参照面的高分辨率成园地层学理论,采用基准面旋回上升和下降二分法,在该凹陷古近系内部识别出3个二级层序界面及5个三级层序界面,建立了辽河盆地东部凹陷古近系高分辨层序地层等时格架,并划分出两个长期基准面旋回和7个中期基准面旋回。在此基础上,研究了不同构造演化阶段的沉积地层充填样式和沉积体系展布,分析了地层格架的主要控制因素,并预测了各层序格架内部有利储集体的发育与分布。指出该凹陷两翼古水系发育,是扇三角洲或浊积扇体发育的有利地区,为寻找隐蔽油气藏指明了方向。

Analysis of Tertiary sequence-stratigraphic framework and genesis in east Liaohe sag.

Based on seismic sections and logging data, the paper uses high-resolution genetic stratigraphy theory taking datum as reference plane, presented by Mr. Cross, and datum cyclic upturn and downturn approach to identify 3 secondary sequence-stratigraphic interfaces and 5 third-order sequence- stratigraphic interfaces inside the Tertiary of the sag, build up Tertiary high-resolution isochronal sequence-stratigraphic framework in east sag of Liaohe basin and divide the Tertiary into 2 long-term and 7 middle-term datum cycles. On that basis, the paper studies fill-up pattern of sedimentary formation and distribution of sedimentary system at different tectonic evolutional stages, analyzes main controlling factors of formation framework and predicts the development and distribution of favorable reservoirs within separate sequence-strati-graphic framework. The paper points out that there was the palaeodrainage pattern developed on both sides of sag,favorable area to develop fan delta or turbidite fan,and pointed out the direction for looking for subtle oil/gas reservoirs.