鄂尔多斯盆地东南部延长组储层成岩体系研究

鄂尔多斯盆地东南部延长组具有丰富的油气资源，储集层为一套致密低渗透砂岩，油气的富集与致密低渗透背景下的高效储层有关。通过铸体薄片、背散射、扫描电镜及能谱分析，结合孔、渗测定，认为:①延长组高效储层的形成与绿泥石环边有密切关系，绿泥石环边的出现是三角洲前缘沉积环境、富黑云母的长石砂岩和咸—微咸水的湖泊水体在空间上耦合的产物；②绿泥石环边抵消了一部分埋藏过程中上覆地层的机械压实作用，减缓了由于压实作用而引起的原生孔隙的减低，而且有抑制石英次生加大的作用；③同生期形成的方解石可以使颗粒呈嵌晶接触，形成致密层，但是这部分方解石量小且分布不均匀；④自生石英在纵向上变化明显，封闭体系中形成的SiO2由于绿泥石环边的抑制作用，以雏晶的形式产出；而半封闭体系中形成的SiO2可向上发生运移，在绿泥石环边不连续或欠发育的层段以加大边的形式产出。通过成岩体系研究，可以明确高效储层的形成机理，指导岩性油气藏的勘探。

Research on Diagenesis System of Yanchang Formation Reservoirs, Southeast Ordos Basin

Yanchang Formation sited in the southern-eastern Ordos Basin has been proven a prolific reservoir unit for hydrocarbon resources.Featured by relatively low porosity and effective permeability,the quality of the reservoir has a significant impact on the migration and accumulation of oil and gas.By analyzing the petrophysic data from thin-section samples,BSE,Energy Spectrum Analysis and core plugs,we reached the following conclusions: 1.The rimming of chlorite has an important control on the reservoir quality...