秦皇岛地区上古生界沉积特征与沉积演化

目前渤海湾盆地中浅层油气资源勘探已进入中、高成熟阶段,上古生界现成为寻找和发现潜在油气资源的重要领域,对上古生界地层特征、沉积相类型及沉积演化过程进行深入研究,对于油气勘探具有一定的指导作用。以沉积学理论为指导,以华北东部地区秦皇岛石门寨上古生界野外露头剖面为基础,通过对其进行详细勘测,识别岩性特征、地层序列以及发育的沉积相类型,明确沉积演化过程。研究表明,秦皇岛地区上古生界自下而上可分为本溪组、太原组、山西组、下石盒子组、上石盒子组及石千峰组,共识别出潮坪相、潟湖相、障壁岛相、台地相、浅水三角洲相及河流相6种主要的沉积相类型;本溪组—太原组发育潮坪相、潟湖相、障壁岛相、台地相,山西组发育浅水三角洲相,下石盒子组—石千峰组发育河流相。研究区上古生界经历了由海相—海陆过渡相—陆相的沉积演化过程。

Sedimentary characteristics and evolution of the Upper Paleozoic strata in Qinhuangdao area

The exploration of oil and gas resources in the middle-shallow strata of the Bohai Bay Basin has entered medium-high maturity stage. The Upper Paleozoic have become an important target for exploring and discovering potential oil and gas resources. The study of stratigraphy,sedimentary facies and evolution of the Upper Paleozoic strata has a certain guiding significance for oil and gas exploration. In this study,guided by the theory of sedimentology,the Upper Paleozoic outcrop profile of Shimenzhai in Qinhuangdao was investigated in detail. The lithological characteristics,stratigraphic succession and sedimentary facies types were identified and the sedimentary evolution process was clarified. The results revealed that the Upper Paleozoic strata in Shimenzhai of Qinhuangdao consisted of Benxi Formation,Taiyuan Formation,Shanxi Formation,Xiashihezi Formation,Shangshihezi Formation and Shiqianfeng Formation from bottom to top. Six types of sedimentary facies,including tidal flat,lagoon,barrier island,platform,shallow water delta and fluvial facies were identified. Tidal flat,lagoon,barrier island and platform facies developed in the Benxi-Taiyuan Formations. Shallow water delta facies developed in the Shanxi Formation, whereas fluvial facies developed in the Xiashihezi,Shangshihezi and Shiqianfeng Formations. The Upper Paleozoic strata of the study area underwent a sedimentary evolution process from marine facies,marine-continental transitional facies to continental facies.