姬塬油田长9油层组成岩作用及孔隙演化特征

运用铸体薄片、扫描电镜、物性分析等方法对姬塬油田长9油层组成岩作用、孔隙演化特征进行研究.结果表明:油层组主要成岩作用为压实-压溶、胶结、溶蚀、交代和重结晶作用.根据成岩特征综合分析,储集砂岩主要形成于水体能量相对较强的三角洲平原分流河道微相环境中,以中-细粒岩屑长石砂岩为主,颗粒较粗,分选为好-中等,因此,原生孔隙度较大,大于30.07%.在压实作用和胶结作用下,孔隙最高可完全损失,但在绿泥石环边存在,其他胶结物相对含量较少的情况下,可保留2.0%～14.5%的残余原生粒间孔.后期长石及浊沸石的溶蚀作用可以形成0.60%～4.25%的次生溶孔,对岩石孔隙度的增加具有一定的贡献.

Diagenesis and pore evolution of Chang 9 reservoir in Jiyuan Oilfield

Diagenesis and pore evolution of Chang 9 reservoir in Jiyuan Oilfield is studied according to casting thin-section,scanning electron microscope and physical property data.The results show that the diagensis types are mainly compaction-pressure solution,cementation,dissolution,metasomatism and recrystallization.According to the comprehensive analysis of diageneses,it is held that the reservoir sandstones are mainly formed in the distributary channel microfacies of delta plain whose water energy is relatively strong.Reservoir lithology is mainly medium-fine lithic-feldspathic sandstone,the sandstone is of coarser grain and good--medium sorting.So the original porosity of the reservoir is greater than 30.07%.After compaction and cementation,the porosity can be lost completely,but when there is rim chlorite and the content of other cements is relatively less,2.0% ～ 14.5% intergranular pore can be remained.In the later stage of diagensis,the dissolution of feldspar and laumontite can produce 0.60% ～ 4.25% secondary dissoluton pore,which makes a contribution to increasing rock porosity.