桂中地区石炭系寺门组砂岩储层特征研究

Study on Sandstone Reservoir Characteristics of Simen Formation of Carboniferous System in Central Guangxi

明确桂中地区石炭系寺门组砂岩储集特性,为油气勘探提供指导意义。本文以前人研究成果为基础,结合现有资料,通过铸体薄片鉴定、扫描电镜观察等手段综合分析,结果表明:(1)桂中地区寺门组砂岩岩石类型主要以细砂岩为主;砂岩分选性以中和好为主,磨圆度主要为次棱状,其次为次圆状和次圆-圆状;砂岩填隙物主要包括粘土杂基和不同类型的胶结物;(2)寺门组砂岩原生孔隙含量相对较高,约占59%,次生孔隙约占31%,裂隙孔约占10%,总面孔率达3.55%;(3)寺门组砂岩孔隙度主要分布在3%~5%之间;砂岩渗透主要分布在小于0.01mD、0.2~0.4mD和大于1mD三个区间中。(4)孔隙度与渗透率但整体较差,表明属于低孔低渗-特低孔特低渗储层。

The sandstone reservoir characteristics of simen formation in carboniferous system in central guangxi are clarified,which provides guiding significance for oil and gas exploration.Based on previous research results,combined with existing data,this paper made comprehensive analysis by means of casting thin section identification and sem observation.The results show that:(1)the sandstone types of simen formation in guizhong region are mainly fine sandstone;Theseparability of sandstone is mainly medium and good,and the roundness is mainly sub-ribbed,followed by sub-circular and sub-circular.Sandstone interstitial materials mainly include clay matrix and different types of cement.(2)the primary pore content of the sandstone in simen formation is relatively high,accounting for 59%,31%of secondary pores,10%of fissure holes,and 3.55%of the total face rate.(3)the porosity of the sandstone in simen formation is mainly distributed between 3%and 5%.Sandstone permeability is mainly distributed in three intervals:<0.01mD,0.2~0.4mD and>1mD.The overall porosity and permeability are poor,which indicates that it belongs to low porosity,low permeability and ultra-low permeability reservoir.(4)compaction and dissolution and cementation are not conducive to reservoir development to some extent;Dissolution can promote formation of favorable reservoirs under certain conditions.