河北宽城蓟县系铁岭组岩石特征及沉积环境分析

Analysis on Petrological Characteristics and Sedimentary Environment of Tieling Formation of Jixian System in Kuangcheng Area of Hebei Province

河北宽城蓟县系铁岭组主要为一套滨海潮坪相碳酸盐岩沉积,剖面实测厚度211.11m,可划分为两段。该套地层岩石类型主要为碳酸盐岩,其次为泥页岩和硅质岩。碳酸盐岩可进一步划分为砾(砂)屑灰(白云)岩、瘤状灰岩、叠层石灰岩、泥(粉)晶灰(白云)岩和泥质灰(白云)岩。根据岩石学特征及沉积构造等相标志,划分为潮上带、潮间带(上、下)和潮下带(上、下)3种沉积环境。地化特征表明,铁岭组一段沉积期气候干燥炎热、海水古盐度较高;铁岭组二段沉积期则气候温暖潮湿、古盐度较低、陆源物质供应较多的环境。石油地质条件初步分析表明,铁岭组灰岩储层具备油气成藏的烃源岩条件、储集条件和盖层条件,该组合找到原生油藏的可能性较大,具有良好的勘探潜力。

The Tieling Formation of Jixian System in Kuangcheng Area of Hebei Province was a set of carbonate deposition of coastal tidal-flat facies with measured profile thickness of 211.1m and from the bottom to top it could be divided into two sections.The rock types of this set of strata were mainly carbonate rocks,the next were mud shale and silicalite.Carbonate rocks could be further divided into calcarenite(dolomite),knollenkalk,stromatolitic limestone(dolomite),micrite(dolomite),and argillaceous limestone(dolomite).According to the petrological characteristics as well as sedimentary structures and other facies' signs,the sedimentary environment could be supratidal zone,intertidal zone and subtidal zone.The geochemical characteristics indicates that the first section of Tieling Formation was formed in a hot,dry climate with higher palaeosalinity,and the second section was formed in a warm,humid climate with lower palaeosalinity and greater supply of terrigenous materials.The preliminary analysis indicates that because of its hydrocarbon source rock conditions,reservoir conditions and caprock conditions,the Tieling limestone reservoir possesses good exploration potential and it is probable to find original petroleum reservoir here,it has a good potential of oil exploration.