准噶尔盆地阜东斜坡区侏罗系三工河组碎屑岩成岩作用及孔隙演化

Diagenesis and Pore Evolution of Jurassic Sangonghe Clastic Rock Formation of Fudong Slope Zone,Junggar Basin

通过岩心观察、薄片鉴定和扫描电镜等技术手段,研究了准噶尔盆地阜东斜坡区三工河组碎屑岩储层的成岩作用及其对储层物性的影响,并分析了储层孔隙的演化形态。研究表明,三工河组储层成岩作用主要包括压实作用、胶结作用和溶蚀作用,压实作用和胶结作用造成岩石储层孔隙的损失分别在50%~80%和10%~30%之间,对储层物性起破坏作用,溶蚀作用形成的次生孔隙和微裂缝是重要的油气储集空间和渗流通道,起到改善储层物性的作用。综合成岩作用、古温度和自生矿物等标志特征,将研究区储层成岩阶段划分为早成岩阶段(A期、B期)和中成岩阶段(A期、B期)。在早成岩阶段,储层孔隙以原生孔隙为主,在中成岩阶段A期,次生孔隙开始发育,并在中成岩阶段B期达到最大值,然后又逐渐减少。

Diagenesis and pore evolution of Sangonghe clastic rock formation of Fudong slope zone are studied by core observation,thin section identification and scanning electron microscope.The results show that diagenesis mainly includes compaction,cementation and dissolution.The former two have negative effect on reservoir physical property,decreasing reservoir pores by 50%-80%,irrespectively;otherwise the latter one is very good for reservoir physical property by providing dissolution pores and micro cracks,which are important reservoir space and permeability channel.The diagenetic stages of Sangonghe Formation are divided into the early part(including period A and period B)and the middle part(including period A and period B).In early diagenetic stage,primary pores predominate in reservoir pores,then secondary pores starts to grow in the period A of the early diagenetic stage,and reach the maximum in the period B,after that they starts to decrease.