惠州地区珠江组下部层序划分及沉积相展布特征

SEQUENCE STRATIGRAPHY DIVISION AND SEDIMENTARY FACIES DISTRIBUTION OF LOWER ZHUJIANG FORMATION IN HUIZHOU AREA

惠州地区是珠江口盆地重要的产油区,随着构造油气藏发现越来越困难,岩性地层油气藏的勘探就显得尤为重要,寻找岩性地层油气藏需要建立研究区精细层序地层格架。依据地震、钻测井等资料,在惠州地区珠江组下部共识别出了7个三级层序。其中,SQ1主要发育三角洲平原沉积;SQ2三角洲向陆后退,滨岸、碳酸盐台地和陆架沉积开始发育;SQ3-SQ7发生了一次大规模的海侵,古珠江三角洲逐渐向陆后退,同时,潮汐和波浪对三角洲前缘砂和滨岸砂进行改造形成陆架砂。

Huizhou area of Pearl River Mouth Basin is an important oil-producing region.With less and less structural reservoirs found,lithologic and stratigraphic reservoirs are essential to be prospected,which needs a more precise sequence stratigraphy framework.According to the comprehensive research of seismic reflection characters,logging and core data,seven third-order sequences were identified in the lower Zhujiang Formation,Huizhou area.The sedimentary facies of SQ1 are mainly delta plain.During the period of SQ2,the delta began to retrograde,shoreland,carbonate platform and shelf sedimentation developed subsequently.A large-scale transgression occurred during the time of SQ3-SQ7,and the paleo-Pearl River delta retreated to the continent,detla front sand and shoreland sand were reconstructed by wave and tide to form shelf sand deposition.