廊固凹陷古近系陆相断陷湖盆层序地层发育主控因素研究

Study on key influential factors of sequence stratigraphy development in fault lacustrine basin

廊固凹陷是一个典型的陆相断陷湖盆,多物源、近物源、相带窄、相变快等特点决定了其层序发育控制因素与被动大陆边缘海相盆地存在较大差异。廊固凹陷古近系可划分出3个二级层序7个三级层序。3个二级层序发育时期与廊固凹陷断陷发育早期、断陷发育中期、断陷改造期相吻合;构造运动在影响二级层序发育的诸多因素中占主导地位。考虑到盆地对构造和气候的沉积响应极为复杂,因此分析三级层序发育的控制因素时,不能把构造、气候等因素分开,而是特别注意各因素对沉积基准面旋回的贡献;认为构造和气候是影响三级层序发育的主控因素。湖进体系域烃源岩发育,低位以及高位体系域储层发育,具有良好的生储盖组合条件。

The Langgu depression is a typical terrestrial rift lacustrine basin. The stratum of Paleogene System in the Langgu depression can be divided into 3 second order sequences and 7 third order sequences. According to the analysis, the authors think that the tectonic movement is the most important factor affecting the second order sequence development. In view of the fact that the controlling factors of the sequence development are extremely complicated, the factors, such as tectonic and climate etc. can not be separated, but a special attention is given to the compound function of the factors to the sedimentation basedevel cycle. The authors think that the tectonic movement and climate are the main factors affecting the third order sequence. Good source rocks formed in transgressive systems tract, the reservoirs usually develop in highstand systems tract and lowstand systems tract, and the contribution of sand bodies and source rocks is great.