东濮地区奥陶系沉积相特征及其演化

东濮地区奥陶系沉积相展布规律认识不清，严重制约了油气的勘探和开发。以露头、岩心、薄片和测录井等资料为基础，通过地层岩石、古生物、沉积结构和沉积构造等特征的分析，对东濮地区奥陶系沉积相进行了精细研究，将奥陶系划分为开阔台地、局限台地、蒸发台地 3 种沉积亚相及 11 种沉积微相，利用“单因素分析多因素综合作图法”编制了奥陶系各沉积期沉积微相平面图，为储层发育有利沉积相带的研究提供了基础，进而结合海平面变化和沉积微相特征，分析了沉积演化规律。研究区开阔台地主要发育颗粒滩、滩间海和云灰坪 3 种沉积微相；局限台地发育多种类型潮坪和泻湖沉积，共计 10 种沉积微相；蒸发台地发育云坪、灰云坪、膏云坪 3 种沉积微相。东濮地区奥陶系在 1 个海退半旋回和 3 个完整的海侵—海退旋回的控制下，蒸发台地、局限台地和开阔台地交互沉积。其中，海退期沉积的冶里组、亮甲山组、上马家沟组下段、峰峰组下段和峰峰组上段上部，主要由局限台地和蒸发台地环境下的各类型潮坪和泻湖沉积构成；海侵期沉积的下马家沟组、上马家沟组上段和峰峰组上段，主要由开阔台地环境下的滩间海和小规模颗粒滩沉积构成，局部发育局限台地沉积。

Characteristics and evolution of the Ordovician sedimentary facies in Dongpu area,Bohai Bay Basin

The understanding of the Ordovician sedimentary facies distribution in Dongpu area is unclear, which restricts the hydrocarbon exploration and development. Based on the data of outcrops, cores, thin sections and logging,combined with stratigraphy, petrology, paleontology, sedimentary texture and structure, the Ordovician sedimentary facies in Dongpu area was divided into three types of subfacies （open platform, restricted platform and evaporate platform）and eleven types of microfacies. According to “single factor analysis and multi factor comprehensive mapping method”,the map of the Ordovician sedimentary microfacies was compiled. The sedimentary evolution rule was analyzed according to the sea level change and sedimentary microfacies characteristics. The open platform developed three types of sedimentary microfacies: grain banks, interbank sea and dolomitic lime flat. The restricted platform developed ten kinds of sedimentary microfacies, such as tidal flat and lagoon. The evaporate platform developed three kinds of sedimentary microfacies: dolomitic flat, lime dolomitic flat and gypseous dolomite flat. The Ordovician have experienced three and a half transgression-regression cycle from Yeli to Fengfeng period in Dongpu area. During regression period, Eli Formation and Liangjiashan Formation, the upper Majiagou Formation, the lower Fengfeng Formation and the top of upper Fengfeng Formation are composed of tidal flat and lagoon subfacies in the restricted platform and evaporation platform. During transgression period, the lower Majiagou Formation, the top of upper Majiagou Formation and the top of Fengfeng Formation are composed of the interbank sea and the small scale grain bank subfacies in open platform and the local restricted platform environment.