沉积学报2025，Vol.43Issue(2)：376-386,11.DOI:10.14027/j.issn.1000-0550.2023.073
黏土沉积微结构特征及其沉积环境
Microstructure Characteristics and Sedimentary Environments of Clay Sediments
摘要
Abstract
[Objective]As an important component of unconventional oil and gas resources,the basic research of shale oil and gas resources has gradually gained momentum.With the continuous microscopization of the study scale,it is increasingly important to study the microstructures of clay sediments.Microstructures of clay sediments have an impact on shale foliation and lamination structure,thus influencing the shale reservoir capacity and development ef-fect.Therefore,further understanding of clay sediments microstructures is conducive to the distribution prediction and exploitation of shale oil and gas resources.[Methods]In addition to being affected to rows and columns by physi-cal action,clay particles also undergo chemical adsorption and flocculation to form floccules with varying degrees.The basic floccule unit is tabular particles or domains,further forming flocs or chains,before finally forming a card house structure under the electric charge.There are many types of structures,reflecting the difference of flocculation.In the sedimentary stage,the physical and chemical factors affecting the flocculation include particle size,particle content,external hydrodynamic strength and flow properties,climate,electrolyte concentration,ion type,pH val-ue,and organic matter.By studying the physical and chemical factors affecting the microstructures of clay sediments and analyzing the other components of mudstone composite particles such as volcanic rock fragments,shale lithics,muddy intraclasts,and fecal pellets,the sedimentary environments of mudstone and shale can be identified and de-scribed.[Results]Flocculation enables clay minerals to be deposited in high-energy hydrodynamic environment.The larger the clay particle size is,the less likely it is to flocculate.Moreover,relatively turbulent water interferes with flocculation and prevents mudstone particles from forming layers.Climatic stratification and storm pressure conduc-tion affect the microstructure of clay deposits.Strong acidic water is conducive to the flocculation of clay particles such as kaolinite.The effects of salinity and organic matter are controversial.The sedimentary environment of shale is diverse,and the sedimentary dynamics include isobaric flow,upwelling flow,gravity flow,viscous underflow,sus-pended sedimentation,tsunami,and storm.However,this study is still in its infancy,and no perfect sedimentary geological model has been established;The quantitative research of floccules and other components of mudstone com-posite particles is insufficient,and artificial intelligence image recognition technology has not been used well;The study on the sedimentary micro-environment and internal association characteristics of marine black shale in western China needs to be deepened;The research technology and method are slightly single.[Conclusions]Based on the qualitative and quantitative description of microstructures of clay sediments and demonstration of sedimentary envi-ronments of mudstone composite particles,fine description of complex and changeable sedimentary environment and sedimentary micro-environment can be achieved,deepening our understanding of the differentiation characteristics of sedimentary environments of shale such as lakes and seas,further revealing the differences in shale reservoir quality within the high-precision range,and laying a foundation for the selection and development of geology and engineering"desserts"in shale;this study has great significance for the deep utilization of shale oil and gas geological resources.关键词
泥页岩/沉积微结构/絮凝/物理化学因素/沉积微环境Key words
shale/sedimentary microstructure/flocculation/physicochemical factor/micro-environment分类
地质学引用本文复制引用
吴冬,邓虎成,解馨慧,刘慧,曹凯旋..黏土沉积微结构特征及其沉积环境[J].沉积学报,2025,43(2):376-386,11.基金项目
国家自然科学基金项目(42072182) （42072182）
中石化西南油气分公司项目(KJ-766-2330)[National Natural Science Foundation of China,No.42072182 （KJ-766-2330）
SINOPEC Southwest China Oil and Gas Branch Project,No.KJ-766-2330] （）
