歧口凹陷滩海区下第三系地震反射特征及层序划分

本文主要利用地震反射同相轴的终止形式和不连续类型 ,对歧口凹陷滩海区下第三系地层进行层序的划分 ,并对不同体系域内部及层序界面的地震反射特征进行较为详尽的描述。研究结果表明 ,歧口凹陷下第三系发育有六个层序 ,每个层序的顶、底界面分别对应于区内七个地震反射界面。不同成因及不同沉积环境的层序内部具有不同的地震反射相。并讨论体系域与油气赋存的关系

Seismic Reflections and Sequence Division of Lower Tertiary in Qikou Sag

The features of seismic reflections of different t ract system by employing the seismic data, logging recorder and some other mater ials are discussed. There are one secondary level sequence and six third level s equences of Lower Tertiary in Qikou sag. Studies of controlling factors of seque nce development show that there are two kinds of sequence developed in Qikou sag and they are tectonic sequence and climate sequence. Sequence 1, sequence 3,seq uence 4, sequence 5 and sequence 6 are tectonic sequences because the boundary f aults controls the space of sedimentation. Sequence 2 is a climate sequence. Dur ing the sedimentary process of the sequence 2, the primary controlling factor on the sequence model is the climate and the changes of the water level of lake ar e not influenced by the uplift of bases rock and the boundary faults. The top and bottom boundaries of each sequence correspond to 7 seismic reflect ion interfaces. The sequences with different sedimentary faces have different se ismic reflection features. Sand bodies have "forereaching reflections", whereas the condensed section has "high amplitude, high continuity and parallel reflecti ons". All those findings could be used to predict the location of sand bodies an d have great significances in directing the petroleum exploration.