冀中坳陷宝坻—桐柏镇变换带形成机制与油气意义

THE FORMING MECHANISM OF THE BAODI-TONGBAIZHEN TRANSFER ZONE IN THE JIZHONG DEPRESSION AND ITS OIL-GAS BEARING

借助三维地震数据体资料,通过构造剖面解释、断层落差计算、平衡剖面构造演化史分析,以及变换带类型的划分,对冀中坳陷宝坻—桐柏镇变换带形成机制进行研究。结果表明:宝坻—桐柏镇变换带属于同向传递型,内部构造样式为地垒和变换断层,而琥珀营断层、杨税务断层等对其起反向调节作用;沙四期变换带南北两侧伸展差异最大,沙三期强烈活动并构造定型,沙二—沙一时期继承性发育并迅速减弱,东营期活动再次变强,之后衰亡,构造活动呈现出阶段式减弱的趋势。结合区域构造分析表明,宝坻—桐桐柏镇变换带为调节大厂—武清凹陷与廊固凹陷伸展差异的构造,构造变形与边界断层活动具有时空匹配性。最新油气勘探研究表明,变换带两侧的强、弱构造域分别发育烃源岩和圈闭,而变换断层则沟通源储,故该区域是油气勘探的有利指向区。

Based on the 3D seismic data, through structural section interpretation, fault throw calculation, structural evolution analysis of balanced section and classification of transfer zone types, the formation mechanism of the Baodi-Tongbaizhen transfer zone in the Jizhong Depression is studied in this article. The results indicate that： the Baodi-Tongbaizhen transfer zone is classified as synthetic collinear-type with horst and transfer fault as the main internal structural styles, while the Hupoying fault and the Yangshuiwu fault provide the conjugate accommodation. The Baodi-Tongbaizhen transfer zone acted intensively in Es4 because of the maximum differential extension, and its active intensity decreased gradually in Es3-Es1. However, the transfer zone fell into weakening again in N-Q after strong reaction in Ed. Hydrocarbon source rocks and traps developed respectively in the strong and weak structural regions on the two sides of the transfer zone, and the transfer faults connected with source reservoirs, which makes the area a favorable oriented region for oil and gas exploration.