珠江口盆地白云北坡韩江组层序格架及富砂沉积体研究

Study on sequence framework and sand-rich sediment body of Hanjiang formation in the north slope of Baiyun sag, Pearl River Mouth Basin

关键词:  珠江口盆地  白云北坡  韩江组  沉积层序  富砂沉积体

Key words:  Pearl River Mouth Basin  the north slope of Baiyun sag  Hanjiang formation  depositional sequence  sand-rich sediment body

摘要:

通过钻井、测井、地震资料分析,并利用层序地层学、地震沉积学等方法,对珠江口盆地白云北坡韩江组的层序地层格架、体系域和富砂沉积体进行研究。结果表明:SQhj1层序体系域可四分为低位体系域(LST)、海侵体系域(TST)、高位体系域(HST)和下降体系域(FSST),SQhj2层序可划分出低位体系域、海侵体系域及高位体系域,其中低位体系域具有两期特征,可细分为LST1和LST2;SQhj1层序的FSST三角洲砂体和SQhj2层序的低位扇体是研究区重要的富砂沉积体,SQhj1层序FSST中的三角洲前缘近端坝、远端坝以及SQhj2层序LST1和LST2中的斜坡水道复合体、盆底扇以及低位楔三角洲前缘砂体等均为有利的富砂沉积体;SQhj1、SQhj2沉积层序发育演化受盆地古地貌、同沉积断裂及断裂坡折带、沉积物供以及海平面变化等因素的影响。

Abstract:

According to the approach of sequence stratigraphy and seismic sedimentary, the sequence framework and sand-rich sediment body of Hanjiang formation in the north slope of Baiyun sag in the Pearl River Mouth Basin were analyzed based on drilling, logging and seismic data. The result shows that the sequence SQhj1 can be divided into low standard system tract (LST), transgression system tract (TST), high standard system tract (HST) and falling stage system tract (FSST). The sequence SQhj2 can be divided into low standard system tract (LST), TST and HST. The LST of sequence SQhj2 can be divided specifically into two parts of LST1 and LST2. Two sand-rich sediment bodies were found in study area, including FSST delta whose sandstone riches in mouth bar and distal bar, and LST fan whose sandstone riches in low standard delta, basin floor fan and slop fan complex. The evolution of depositional sequence was influenced by geomorphology of basin, syndepositional fault and faulted slope break zone, sediment supply and sea-level change.