淮北青东井田早二叠世浅水三角洲沉积特征及模式研究

利用研究区内162口钻孔岩芯精细观察资料及100多个薄片粒度分析样,系统地分析了研究区内沉积特征,建立了淮北青东井田早二叠世山西组、下石盒子组地层的浅水三角洲沉积模式.研究认为研究区是浅水三角洲沉积体系由东南入海而成,山西组主要发育前三角洲、三角洲前缘、三角洲平原亚相,可细分为远砂坝、河口砂坝、分流河道、分流间湾等微相.下石盒子组主要发育上三角洲平原,可细分为分流河道、分流间湾等微相.研究发现,浅水三角洲发育于台地背景下,水体浅,水深一般小于100 m,主要由三角洲平原亚相组成,分流河道是其主要的沉积微相,三角洲前缘亚相和前三角洲亚相的沉积厚度较薄.在上述研究基础上,建立了整个研究区的浅水三角洲沉积模式.

Study of Sedimentary Characteristics and Model of Shallow-Water Delta during the Early Permian in Qingdong Well Field of Huaibei

Based on 162 borehole meticulous core observation and more than 100 thin section size analysis,sedimentary characteristics and mode of shallow-water delta of Shanxi Formation and Lower Shihezi Formation in Qingdong well field of Huaibei are analyzed. It is realized that the study area is made from shallow-water delta sedimentary system to the southeast into the sea. Prodelta,delta front and lower delta plain subfacies are developed in Shanxi Formation,which can be further classified into distal bar,mouth bar,underwater distributary channel and underwater distributary-interchannel and so on. Upper delta-plain subfacies is developed in Lower Shihezi Formation,which can be further classified into distributary channel and interdistributary bay. The study finds that shallow water delta is developed in the background of the platform. Water body is shallow,and water depth is generally less than 100 m. It is mainly composed of delta plain subfacies,and distributary channel is the main sedimentary microfacies. The sedimentary thickness of prodelta and delta front is thinner. Based on the above research,the shallow-water delta depositional model is set up in the whole study area.