摘要
为了弄清新疆三塘湖盆地马朗凹陷芦草沟组泥页岩层系中SiO_2对储集层物性、脆性等特性的影响,通过全岩和黏土矿物X衍射、岩石力学性质、阴极发光、扫描电镜及电子能谱等实验手段对其中SiO_2的赋存状态进行了研究,初步探讨了SiO_2不同形态赋存的机理,并在此基础上探究了石英含量对储层的影响。研究表明:凝灰岩、泥页岩和粉砂质泥岩中二氧化硅多以非晶态形式存在。二氧化硅在凝灰岩中多呈不规则球粒状,而在泥页岩和粉砂质页岩中无固定形态。凝灰质泥岩、凝灰质白云岩和白云岩中二氧化硅呈现一定的晶体形态。在凝灰质泥岩中,二氧化硅以自生石英形态聚集呈条带状,在凝灰质白云岩中则以自生石英形态发育于孤立的孔、洞之中,而白云岩中二氧化硅只能生长成Opal-A/Opal-CT阶段。凝灰质成分及其脱玻化作用为自生石英的生长提供了二氧化硅和生长空间,是控制SiO_2赋存状态的根本因素。此外,储集层孔隙度、渗透率和抗压强度都与石英含量呈一定正相关性,泊松比则与其呈负相关性。
In order to figure out the influence of SiO2 to reservoirs property,such as physical property and brittleness,in the shale system of middle Permian series Lucaogou Formation in Malang sag,Santanghu Basin in Xinjiang,SiO2 occurrence and origins of different occurrences for samples from the Lucaogou Formation was studied by a series method,including XRD of whole rock and clay minerals,mechanical properties of rocks,cathode luminescence,SEM and EDS,then on the basis of these analysis,the effect of the content of quartz on reservoir property was explored.The research indicates that silica in tuff,mud shale and silty mudstone is mainly amorphous and displays irregularly in tuff,while can be any geometry in others.However,silica in tuffaceous mudstone and tuffaceous dolomite shows crystal morphology.Silica in tuffaceous mudstone shows as authigenic quartz gathering like ribbon,and occurs separately in tuffaceous dolomite,while silica in dolomite is in the stage of Opal-A/Opal-CT.Tuffaceous matter and its devitrification provide silica and space for authigenic quartz formation.They are the key factors of SiO2 occurrence.Furthermore,porosity,permeability and compressive strength have a positive relationship with the content of quartz,while Poisson＇s ratio has a negative relationship with quartz.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2016年第6期1220-1235,共16页
Acta Geologica Sinica
基金
国家自然科学基金项目“湖相富有机质页岩自生石英形成及其页岩油地质意义”(编号:41272156)资助的成果
关键词
二氧化硅
自生石英
脱玻化作用
三塘湖盆地
马朗凹陷
amorphous silica
authigenic quartz
devitrification
SEM
Santanghu Basin
Malang Sag
