歧口凹陷古近系东二段沉积体系空间配置研究

综合岩心、录井、测井、3D地震、生物组合等资料,对东二段沉积体系进行了重点研究。分析认为,该时期研究区主要发育4种沉积体系。在此基础上结合砂分散体系分析,揭示了东二段沉积期沉积体系的空间配置关系,重建了沉积体系域。其中,扇三角洲发育于沧东断层控制的陡坡背景边缘,呈裙带状分布;辫状河三角洲主要发育在凹陷北部的北塘地区,向南延伸至长芦-新港断层下降盘演变为远岸水下扇;源于北部的远岸水下扇受活动性较强的滨海断层、港西断层和歧中断层的影响,呈多阶梯状分布;埕宁隆起刘官庄地区和沙垒田隆起西部发育较小规模的辫状河三角洲;湖泊的发育主要受控于长芦-新港断层、滨海断层、港西断层、张东断层和歧东断层,滨浅湖发育于增幅台、王岗庄、曹妃甸等地区,半深湖-深湖位于驴驹河、高尘头等地区。基于上述研究,预测研究区存在三个有利勘探区带。

Distribution of Paleogene Sedimentary Systems of the Second Member of the Dongying Formation in the Qikou Sag

Integrated study of well core,drilling,logging,3D seismic,and biological association shows that there are four sedimentary systems in the second member of the Dongying Formation in the Qikou sag:fan delta,braided delta,distal subaqueous fan,and lake systems.And the distribution of the sedimentary systems as demonstrated by the sand bodies may be concluded as follows:1) crony-like fan delta developed in steep background which was controlled by the Cangdong fault;2) braided delta developed in the Beitang area of the northern Qikou sag,and evolved into 3) distal subaqueous fan near the downthrow wall of the Changlu-Xingang fault and ladder-like sediment system was controlled by the Binhai fault,Gangxi fault and Qizhong fault;while 4) lake system was mainly controlled by the Changlu-Xingang fault,Binhai fault,Gangxi fault,Zhangdong fault and Qidong fault,within which the shallow lake system located in the Zengfutai,Wanggangzhuang and Caofeidian areas,where as the semi-deep lake system and deep lake system located in the Lvjuhe and Gaochentou areas.Based on the research,three favorable areas are proposed,i.e.,fan delta front sand in the Banqiao sag,braided delta sand in the northern Qikou sag,and distal subaqueous fan sand in the middle of the Qikou sag.