饶阳凹陷大王庄地区古近系沙一段至东营组层序地层与沉积体系分析

STUDY ON SEQUENCE STRATIGRAPHY AND DEPOSITIONAL SYSTEM FROM THE FIRST SEGMENT OF SHAHEJIE FORMATION TO DONGYING FORMATION IN DAWANGZHUANG AREA,RAOYANG SAG,CENTRAL HEBEI PROVINCE

运用高分辨率层序地层学理论和分析方法,综合研究钻井、测井和三维地震资料,在饶阳凹陷大王庄地区古近系沙二段上亚段至东营组中识别出6个层序界面,将其划分为1个超长期基准面旋回(二级层序)Ssq1和5个长期基准面旋回(三级层序)Sq1、Sq2至Sq5。综合分析认为大王庄地区古近系沙一段至东营组沉积发育在饶阳凹陷断陷演化阶段的断陷萎缩期,发育辫状河三角洲、湖泊和河流3类沉积体系,在等时地层格架约束下,阐述了各类沉积体系在工区的亚相、微相类型,系统分析了沙一段至东营组的沉积相类型、平面分布特征及沉积体系演化特征,指出Sq2基准面下降半旋回所形成的辫状河三角洲前缘分流水道砂和席状砂为有利的储集砂体。

One super-term stratigraphic base level circle(the 2nd sequence) Sq1 and the corresponding 3 long-term stratigraphic base level circles(the 3rd sequence) Sq1、Sq2、Sq3、Sq4 and Sq5 could be distinguished:the first segment of Shahejie Formation and Dongying Formation within the six sequence boundaries in Dawangzhuang area,Raoyang sag by using the ways and principles of the high resolution sequence stratigraphy.It is pointed out after the integrate analysis that the first segment of Shahejie Formation is the outcome of the the rift depression vanishing stage in Raoyang sag.Within the correlation framework,three-type depositional systems are identified,namely braided river delta、lake and fluvial depositional systems and the composition of the depositional system and facies development in the cycles are analyzed.It is pointed out that Sq2 cycles are the most favorable segment of the reservoir rock,and the rock of the braided river delta is the target of the oil exploration.