深层碎屑岩自生矿物成因机理及其对储层物性的影响——以渤海歧南断阶带侏罗系为例  

Genesis Mechanism of Authigenic Minerals in Deep Clastic Rocks and Its Influence on Reservoir Physical Property: An Example from the Jurassic in Qinan Fault Step Belt, Bohai Sea, China

作　　者：郭颖 杨波 韩自军 李果营 吴庆勋 叶涛 Guo Ying;Yang Bo;Han Zijun;Li Guoying;Wu Qingxun;Ye Tao(Tianjin Branch,CNOOC China Limited,Tianjin 300459,China)

机构地区：[1]中海石油(中国)有限公司天津分公司,天津300459

出　　处：《吉林大学学报（地球科学版）》2021年第4期973-990,共18页Journal of Jilin University：Earth Science Edition

基　　金：国家科技重大专项(2016ZX05024-003)。

摘　　要：自生矿物特征和成因机理对深层碎屑岩储层物性具有重要影响。以渤海海域歧南断阶带侏罗系为例,通过岩心、薄片、扫描电镜、电子探针、同位素、包裹体、X衍射分析等技术手段,对研究区侏罗系深层碎屑岩储层自生矿物的类型、特征、成因机理及对优质储层发育的控制作用进行研究。结果表明:研究区侏罗系碎屑岩属于中孔-低渗储层,非均质性强;主要自生矿物类型为硅质矿物、碳酸盐矿物、黏土矿物3类;早期形成的硅质石英衬垫和碳酸盐胶结物控制了孔隙的发育和演化,沿颗粒表面分布的早期硅质石英衬垫有效抑制了后期石英加大生长,并增强了岩石的抗压能力,有利于原生孔隙保存;早期碳酸盐胶结物增强了储层抗压实能力,并为后期储层遭受溶蚀形成溶蚀孔提供了物质基础,有利于高孔隙储层形成;黏土矿物控制了储层渗透率差异,储层渗透率与自生高岭石体积分数呈正相关性,较高渗透率储层分布于侏罗系中段高岭石富集带内。研究区侏罗系碎屑岩发育原生孔隙体积分数高、微晶石英衬垫发育的Ⅰ类有利储层和粒间溶蚀孔隙较发育、具显著表生成岩作用特点的Ⅱ类有利储层,二者孔隙演化存在明显差异。Ⅰ类有利储层主要受早—中成岩期微晶石英衬垫抗压实作用控制,浅层和深层均可发育高孔隙储层;Ⅱ类有利储层主要受表生期风化淋滤作用控制,可在风化壳附近形成优质储层,整体上Ⅰ类储层物性优于Ⅱ类。The characteristics and genetic mechanism of authigenic mineralshave important influence on the physical properties of deep clastic rock reservoirs. By taking the Jurassic clastic reservoirsin Qinan fault step belt of Qikou sag, offshore Bohai Sea as anexample, the types, characteristics, genetic mechanism of authigenic minerals, and their controlling effect on the development of high-quality reservoirs were studied on the basis of core observation, thin section identification, scanning electron microscope, electron probe, isotope, inclusion, and X-diffraction analyses. The results show that the Jurassic clastic reservoirs in the study area have moderate porosity and low permeability with strong heterogeneity. The main types of authigenic minerals are siliceous minerals, carbonate minerals, and clay minerals. The early microcrystalline quartz liners are distributed along the surface of the particles that effectively inhibited the overgrowth of late quartz and enhanced the resistance to compactionof the rock, which was beneficial to the preservation of primary pores;The early carbonate cementation enhanced the anti-compaction ability of the reservoirs, and provided the material foundation for the formation of dissolution pores generated by the late dissolution, which was conducive to the formation of high-porosity reservoirs;The clay minerals controlled the difference in reservoir permeability, which is positively correlated with the content of authigenic kaolinite. The reservoirs with higher permeability are distributed in the kaolinite enrichment zone in the middle part of the Jurassic. Two types of favorable reservoirs are developed in the study area: Type Ⅰ is with high content primary poresand well-developed microcrystalline quartz gaskets;Type Ⅱ is with more developed intergranular dissolution pores and more obvious epidiagenesis characteristics, and they are significantly different in pore evolution. Type Ⅰis mainly controlled by the compaction resistance of the microcrystalline quartz liners in the e

关 键 词：自生矿物 成因机理 储层物性 歧南断阶带 侏罗系 深层碎屑岩 

分 类 号：P544[天文地球—构造地质学]