辽东湾坳陷东北部新近系馆陶组辫曲过渡型河流沉积特征

辫曲过渡型河流是发育于辫状河向曲流河演化过程中的一种河流类型.综合现代沉积类比、构造演化分析、岩心分析与地震正演,对渤海湾盆地辽东湾坳陷东北部新近系馆陶组沉积体系类型及沉积演化规律进行了研究,并在层序分析的基础上,对馆陶组辫状河、曲流河与辫曲过渡型河流等3种沉积类型的宏观和微观沉积特征、成藏条件进行了对比.研究结果表明...

Sedimentary characteristics of braided-meandering transitional river of Neogene Guantao Formation in northeastern Liaodong Bay Depression

Braided-meandering transitional river is a type of river developed in the process of braided river transforming to meandering river. Based on modern sedimentary analogy，tectonic evolution analysis，core analysis and seismic forward modeling analysis，the sedimentary system types and sedimentary evolution law of Neogene Guantao Formation in northeastern Liaodong Bay Depression of Bohai Bay Basin were studied. Under the control of sequence strata，the macro and micro sedimentary characteristics and reservoir accumulation conditions of three sedimentary systems of Guantao Formation，including braided river，meandering river and braided-meandering transitional river，were compared. The results show that： （1）During the sedimentary period of Guantao Formation in northeastern Liaodong Bay Depression，the sedimentary system gradually transited from braided river to meandering river，and braided-meandering transitional river developed in the middle Guantao Formation.（2）The braided-meandering transitional river are characterized by strong hydrodynamic force，combined vertical accretion and lateral accretion，moderate reservoir development and maturity，low-frequency interbedded sandstone and mudstone，and superposition of box-shaped and bell-shaped logging curves.（3）Compared with the reservoirs of braided river and meandering river，the braided-meandering transitional river reservoirs have better lateral connectivity，large-scale mudstone interlayers developed at vertical intervals，and better reservoir-cap assemblage conditions，which determines that they are more conducive to large-scale hydrocarbon accumulation.