鄂尔多斯盆地镇泾地区中生代地层剥蚀厚度估算及古构造恢复

鄂尔多斯盆地镇泾地区中生界及以上地层主要经历了三叠系-侏罗系、侏罗系延安组-直罗组、侏 罗系-白垩系和白垩系-第四系地层不整合面对应的 4 期地层抬升与剥蚀事件。 综合利用压实曲线外 推法及地层趋势对比法估算了三叠纪以来 4 期构造抬升事件导致的地层剥蚀厚度，并对其进行了对比 与验证，采用盆地模拟方法恢复了研究区长 8 油层组顶面构造演化过程。 结果表明，三叠纪末延长组地 层剥蚀厚度为 345～465 m、中侏罗世末延安组地层剥蚀厚度为 150～220 m，侏罗纪末安定组地层剥蚀 厚度为 160～250 m，晚白垩世-新近纪末志丹群剥蚀厚度为 980～1 280 m。 构造沉降及抬升与剥蚀共 同控制了研究区延长组地层的构造形态，自三叠纪以来，其表现为掀斜构造演化过程。

Estimation of denudation thickness of Mesozoic strata and paleostructure restoration in Zhenjing area,Ordos Basin

The Mesozoic and the overlain strata in Zhenjing area underwent four stages of formation uplift and denudation events corresponding to the unconformity surfaces of Jurassic-Triassic, Jurassic Yanan Formation-Zhiluo Formation, Jurassic-Cretaceous and Cretaceous-Quaternary. Compaction curve extrapolation method and formation tendency correlation method were used to estimate the denudation thickness resulted by the four stages of tectonic uplift events from Triassic, and the denudation thicknesses from different stages were compared. Basin numerical modeling method was applied to restore the structural evolution process of the top surface of Chang 8 oil reservoir set. The result shows that the strata denudation thickness of the end of Triassic Yanchang Formation is 345-465 m, the strata denudation thickness of the end of Middle Jurassic Yan’an Formation changes from 150 m to 220 m, and thestrata denudation thickness of the end of Jurassic Anding Formation is 160-250 m. However, the denudation thickness of the end of Late Cretaceous-Neogene Zhidan group is much more than that of the other three stages, and it varies from 980 m to 1 280 m. The structural form of Yanchang Formation in the study area was controlled by tectonic subsidence and uplift and denudation, with tilting structural evolution process from Triassic.