霸县凹陷构造特征及新生代构造演化

霸县凹陷是由牛东断层控制的西断东超的新生代箕状凹陷。本文以连片三维地震资料为基础，采用断层落差法和平衡剖面技术研究了凹陷的构造特征与构造演化特征。结果表明：牛东断层可以分为3 段，北段为一系列NE-NNE 向东倾断阶带，中段为铲式-略微坡坪式断裂带，南段为帚状断裂带。霸县凹陷相应划分出北部、中部、南部3 个构造单元。牛东断层具有分段活动的特点，具体表现为：早期（Ek-Es⁴）中北段活动强烈、中期（Es³-Es²）中南-中北段活动强烈、晚期（Es¹-Ed）整体强烈活动、北段剧烈活动，活动强度具有自南向北迁移的规律，其活动性差异控制了变换带的形成和凹陷的构造格局。霸县凹陷新生代构造演化可以分为古近纪的裂陷阶段和新近纪以来的拗陷阶段， 其中古近纪分为Ek-Es⁴ 较强裂陷期、Es³-Es²弱裂陷期和Es¹-Ed 强裂陷期，由此控制烃源岩、储层的形成、油气的运聚和分布。

Structural characteristic and Cenozoic tectonic evolution in Baxian sag

Baxian sag, controlled by the Niudong fault, is a Cenozoic half-with faulting in west and overlap in east. Based on continuous 3D seismic data, various methods including fault throw method, balanced cross-section technique are adopted in this paper to analyze the structural characteristics and Cenozoic evolutionary process. The results show that Niudong fault can be divided into three sections: In north, it shows a series of NE-NNE fault terrace zone dipping east; in central, it presents as listric fault; in south, it is characterized as brush structure. Baxian sag is divided into three sections accordingly. Niudong fault shows a sectional activity in Paleogene, and activity strength migrates from south to north with time. There are mainly three periods: In Ek-Es⁴ period, north-central segment present a stronger activity; in Es³-Es² period, south-central and north-central segments became stronger; in Es¹-Ed period, the whole fault has strong activity while the north has stronger activity. Baxian sag underwent rifting stage in Paleogene and depression stage in N-Q. And the rifting stage is subdivided into three sub-rift screens: Ek-Es⁴ period、Es³-Es² period and Es¹-Ed period. The evolution characteristics of Baxian sag had an appreciable effect on development and distribution of source rocks, reservoirs, traps.