渤海湾盆地新北油田古近系油气成藏特征

Hydrocarbon Accumulation Characteristics of Palaeogene in Xinbei Oilfield,Bohai Bay Basin

新北油田位于渤海湾盆地垦东凸起北部,勘探程度较低。为认识新北油田古近系成藏规律,通过对该区古近系地层展布分析、单井相分析、连井剖面对比以及针对油气来源、输导路径、圈闭和油藏类型分析得出以下结论:新北油田古近系沙河街组和东营组地层自北向南层层超覆于垦东凸起之上,其中沙河街组以滨浅湖滩坝沉积为主,东营组6砂组发育近岸水下扇沉积相,东营5-1砂组发育扇三角洲沉积相;受沉积相控制,沙河街组与东营组6砂组储层主要沿湖盆边缘展布,东营5-1砂组储层全区发育;储层与断层、不整合面配置发育了构造、地层超覆和岩性上倾尖灭圈闭;来自桩东凹陷的油气,沿断层、砂体以及不整合面进入圈闭,形成了构造、地层超覆以及岩性上倾尖灭油气藏。

Xinbei Oilfield with low exploration degree,lies in the northern slope of Kendong Uplift.In order to study reservoir characteristics and accumulation rule of Palaeogene in Xinbei Oilfield,the stratigraphic sequence,sedimentary characteristics and hydrocarbon accumulation characteristics were studied.The formation of Palaeogene consists in ascending order of Dongying and Shahejie Formation.The sedimentary facies of Palaeogene mainly included fan dalta,shore-shallow lacustrine and subaqueous fan.The hydrocarbon mainly comes from the Zhuangdong Sag,the hydrocarbon migration model can be divided into two types:fault-sand-fault and fault-unconformity-fault.By structure characteristics and hydrocarbon migration mode control,the oil reservoir types are mainly structural reservoir and stratigraphical overlap reservoir.