鄂尔多斯盆地三叠系延长组地震层序解释

以层序地层学理论为指导,以地震勘探资料为依据,通过地震层序解释,明确了鄂尔多斯盆地延长组层序关键界面识别标志,划分了新的层序,并建立了延长组三级层序格架.提出在延长组传统分层中存在明显穿时现象,延长组中部SQ4底界穿时最为明显,大致规律是:在湖盆中心的华池、合水地区,SQ4底界位于长7上部,向外围的北东和南西方向,SQ4底界逐渐抬升到长6_1底部.此外,还分析了新的层序划分对油气富集的控制作用.

Seismic Sequence Analysis on Triassic Yanchang Formation, Ordos Basin

Based on sequence stratigraphy theory, the seismic sequence of the Triassic Yanchang Formation of the Ordos basin was analyzed and 6 third-order sequences were recognized. The result also shows that obvious diachronous phenomena exist in the traditional rock stratigraphic unit, especially in the middle part of Yanchang Formation, for example, the bottom of the SQ4 uprises from Chang 7_1 in the centre of the lake basin to the Chang 6_1 north-eastwardly at the Wuqi-Yan'an, north Shaanxi and south-westwardly at the Zhenyuan-Jinchuan area, east Gansu. This paper also made an analysis on oil enrichment controlled by sequence boundaries and flooding surfaces.