辽河滩海地区东部断层走滑特征

辽河滩海地区东部现有的地震资料信噪比偏低,导致对主要的走滑断层——燕南断层、燕东断层的构造特征认识不清,制约了研究区内的勘探工作。在叠前深度偏移地震资料精细解释的基础上,利用构造演化分析,结合断层平面展布特征以及应力场机制,以滩海地区东部的燕南断层、燕东断层及东部凹陷内走滑断层3条主走滑断层和1条浅层走滑断层燕东东断层为研究对象,分析辽河滩海地区断层走滑作用及特征。研究结果表明:燕南断层、燕东断层、东部凹陷内走滑断层和燕东东断层,走滑作用发育的时间、强度以及所受区域应力场均不相同,燕南断层以及东部凹陷内的走滑作用主要发生在渐新世中、晚期,燕东断层走滑作用发生在渐新世早期,而燕东东断层则是新构造运动浅层挤压走滑的产物。走滑断层特征的重新认识对辽河滩海地区后续勘探工作具有一定参考意义。

STRIKE-SLIP CHARACTERISTICS OF THE EASTERN FAULT IN LIAOHE OFFSHORE

The low signal-to-noise ratio of the existing seismic data in East Liaohe Offshore results in the unclear understandings of the tectonic characteristics of the main strike-slip faults-Yannan Fault and Yandong Fault,thus the exploratory task in the study area has been constrained.Based on the interpretation results of the pre-stack depth migration seismic data,by means of the structural evolution analysis,integrated with the planar spread features of the faults and stress field mechanism,taking Yannan Fault,Yandong Fault,three main strike-slip faults in East Sag and one shallow strike-slip fault (East Yandong Fault) as the research objects,the fault strike-slipping actions and characteristics in Liaohe Offshore were figured out.The study achievements show that there are a certain differences in the strike-slipping action time,strength and impacted regional stress field for Yannan Fault,Yandong Fault,strike-slip faults in East Sag and East Yandong Fault,the strike-slipping actions of Yannan Fault and faults in East Sag were generated in Middle and Late Oligocene,the strike and slipping of Yandong Fault were in Early O ligocene,while East Yandong Fault is the product of the shallow compact strike-slip of the new structural movement.The new understandings of the strike-slip fault characteristics possess a certain reference significance for the later exploratory work.