Study On The Causes And Characteristics Of Authigenic Chlorite Zhundong Fu North Slope Region Jurassic Toutun River Formation Sandstone

Study area belongs to the typical continental slope East.The Jurassic Toutun River formation is one of the important exploration strata in the North Slope and has received widespread attention.Although many scholars have gained a lot of knowledge about Jurassic source rocks and sedimentary facies,they are mostly based on the whole Junggar Basin.Authigenic chlorite cements are widely developed in the Toutun River formation sandstone.According to a series of test methods such as X diffraction,thin section observation and scanning electron microscope analysis,it is known that the clay minerals in the sandstone of the Toutun River formation in the northern part of the north area are very developed,and most of them are mainly chlorite rings.The authigenic chlorite is common in sandstone reservoir,in order to further enrich the clastic reservoir of clay mineral research,and provide an important geological basis for Fu North area of Jurassic Toutun River formation further oil and gas exploration,Through core sampling observation,cast thin section,scanning electron microscope,X diffraction,NMR methods,alignment of occurrence,causes of authigenic chlorite cements in Junggar basin area north of Toutun River Fu Group in the sandstone reservoir and its influence on the physical properties of the reservoir are studied,The results show that:(1)The Toutun River formation sandstone reservoir of authigenic chlorite cementation common,formed in the early diagenetic stage,mainly in the pore lining cement output;(2)Toutun River group debris content is very high,The volcano rock and tuff debris from the north east direction,provided the source material sufficient for formation of authigenic chlorite film,Authigenic chlorite is formed by alteration of volcanic rock fragments and tuff cuttings under certain conditions;(3)Toutun River group to improve the mechanical strength of authigenic chlorite coated rock and anti compaction ability is limited,only when the authigenic chlorite rim showed a continuous distribution with a certain thickness,can inhibit the nucleation and inhibition of quartz quartz overgrowth,authigenic chlorite in primary pores retain more at the same time,also occupied the primary pores formed the mineral intercrystal pore,but significantly blocked the throat,resulting in the decrease of reservoir permeability;(4)Combination of quantitative and statistical data analysis found that the Toutun River formation of authigenic chlorite coating thickness of the critical value is 8?m,when the coating thickness <8?m,with the increase of authigenic chlorite coating thickness,compaction mitigation ability is strong,and can inhibit the conditions of authigenic quartz formation,reservoir physical property is better;once the coating thickness >8?m,coated on clogging shouted the dominant,self was negatively related to chlorite coating thickness and reservoir property,unfavorable reservoir development.