歧口地区港西凸起周缘沙二段沉积体系特征

Sedimentary features of the second member of Shahejie Formation in the Gangxi Uplift of Qikou Area

为明确歧口地区港西凸起在沙二段沉积期沉积体系分布格局,基于地震、测井、录井、岩心及薄片等资料,结合轻重矿物分布特征,分析沉积古背景及沉积特征,总结港西凸起两翼不同的砂体发育模式,明确有利储集相带及其控制因素。结果表明:港西凸起两翼沉积特征存在明显差异,南翼歧北地区受港西凸起、孔店-羊三木凸起及燕山物源的影响,主要为宽缓湖湾沉积,从西南向北东方向依次形成粒屑滩-滩坝-砂质云坪-扇三角洲相的沉积格局;北翼港北地区受港西凸起物源的影响,发育断槽输砂及斜坡控砂的砂体分布模式,主要为扇三角洲和滩坝沉积;港西凸起两翼发育的扇三角洲水下分支河道砂体及沿岸大面积分布的滩坝砂体厚度适中、储集物性较好,且分布稳定,为油气聚集的优势储集相带。

In order to determine the distribution of sedimentary systems in period of the second member of Shehejie Formation in the Gangxi Uplift of Qikou,we used the data of seismic,logging,core and thin slice based on fine structure interpretation and evolution,combined with the distribution characteristics of light and heavy minerals,analyzed the paleo-sedimentary environment and features.The sand body model developed in the pendants of Gangxi Uplift was summarized and the favorable reservoir facies and its controlling factors were shown clearly.The study suggested that there were significant differences in the sedimentary characteristics of the two pendants of Gangxi Uplift.The south area was affected by the source of Gangxi Uplift,Kongdian-Yangsanmu Uplift and Yanshan,and deposited broad lake.It formed granular beach,beach bar,sandy dolomitite flat and fan delta facies.The north area which was affected by the source of Gangxi Uplift,showing that sandbody transporting in grooves and controlled by slope developed fan delta and beach bar.The fan delta and beach bar in the two pendants of Gangxi Uplift,are featured by medium thickness,good reservoir properties and distributional stability.They showed favorable belt of petroleum.