鄂尔多斯盆地奥陶系白云岩成因及白云岩储层发育特征

发布时间：2018-03-26 21:23

本文选题：鄂尔多斯盆地　切入点：奥陶纪　出处：《天然气工业》2017年01期

【摘要】：白云岩是鄂尔多斯盆地奥陶系最重要的有效储集岩类,由于岩石结构及产状特征复杂多变,对其成因认识尚存在争议。为此,综合宏观区域地质背景、微观岩石结构、矿物学及岩石地球化学等分析研究成果,将该区奥陶系白云岩划分为泥—细粉晶、粗粉晶、细(中)晶3种类型,指出其分别形成于"蒸发泵吸准同生云化""淡水与富镁卤水混合水云化""回流—渗透云化"3种不同的白云岩化成岩作用环境,并在层位及空间展布上表现出明显的"层控性"及"区位性"分布特征。进而探讨了白云岩的成因,结果认为:① 3种白云岩化作用在时空演化特征上表现出一定的相关性,即均与蒸发背景下的膏盐矿物沉淀有着密切的成因联系;②白云岩中所发育的溶孔、白云石晶间孔及生物格架孔等主要孔隙类型分别形成于3种白云岩类型中,对白云岩类型表现出一定的"专属性",表明孔隙成因与白云岩化成岩作用环境密切相关;③白云岩有效储层的发育与分布主要受原始沉积相带、大区白云岩化的成岩作用环境、相对海平面变化产生的层序界面等3类要素的控制。
[Abstract]:Dolomite is the most important effective reservoir rock of Ordovician in Ordos Basin. Because of the complex and changeable characteristics of rock structure and occurrence, there is still controversy on its origin. According to the results of mineralogical and petrogeochemical analysis, dolomite of Ordovician system in this area is divided into three types: mud-fine silt, coarse silt, fine (middle) grain, etc. It is pointed out that they are formed in three different dolomite diagenesis environments: evaporative pump suction syngenic cloud formation, mixed water clouding of fresh water and massium-rich brine, and "refluxing and permeating cloud formation". The distribution characteristics of "stratification" and "location" are obvious on the horizon and spatial distribution. Furthermore, the origin of dolomite is discussed, and the results show that there is a certain correlation in the evolution characteristics of space-time evolution of the dolomitization of 1: 13 kinds of dolomitization. That is to say, both of them are closely related to the deposit of gypsum minerals in evaporative background. The main pore types, such as dolomite intergranular pore and bioglass pore, are formed in three dolomite types, respectively. It shows that pore genesis is closely related to dolomite diagenesis environment. The development and distribution of effective reservoir of dolomite are mainly affected by the original sedimentary facies zone and diagenetic environment of dolomitization in large area. The control of three kinds of elements such as sequence interface produced by relative sea level change.
【作者单位】：中国石油长庆油田公司;低渗透油气田勘探开发国家工程实验室;
【基金】：“十三五”国家科技重大专项“大型油气田及煤层气开发”(编号:2016ZX05004-006)
【分类号】：P618.13;P588.245

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