【摘要】 珠江口盆地是研究深水沉积过程和南海油气勘探的热点区域。利用地震、测井和钻井岩屑等资料,发现珠江口盆地深水区晚渐新世至中中新世期间,发育混合沉积体系。该混合沉积体系岩相主要表现为碳酸盐岩与硅质碎屑以不同比例的混合堆积,垂向岩相变化存在突变式、渐变式和交互式三种递变类型。根据地震反射以及岩相特征,混合沉积体系可划分为4个沉积阶段:第1阶段主要为原位混合沉积,形成渐变式或突变式混合沉积;第2阶段为相缘混合,产生渐变式混合沉积层系;第3、4阶段为间断混合,形成交互式混合沉积。在硅质碎屑沉积为主的背景下,混合沉积由于碳酸盐碎屑的加入,可能会形成潜在的油气储层,对今后深水油气勘探有一定的启示意义。更多还原

【Abstract】 The Pearl River Mouth Basin is a hotspot to the study of deep-water sedimentation and petroleum exploration in the South China Sea.This study is contributed to the mixed depositional system developed from late Oligocene to Middle Miocene,based on seismic,logging and cuttings data.This mixed depositional system is characterized by the mixtures of different proportions of carbonate and siliciclastic debris.In the vertical sequence,there are three types of lithofacies,i.e.mutational,tapered and alternated types.Based on seismic reflections and lithofacies characteristics,the formation of the mixed depositional system may be further divided into four stages and three mixing processes:the stage 1 of in-situ mixing;the stage 2 of mixing at facies border;and the stage 3 and 4 of punctuated mixing.It is proposed in this paper that these mixed depositional sequences developed in a siliciclastic-dominated environment,may be significant to the formation of potential petroleum reservoirs and has implications for deep-water petroleum exploration in the South China Sea.更多还原