塔里木盆地巴麦地区巴什托—亚松迪区块小海子组滩相储层特征研究

Research on Point Beach Facies Reservoir Characteristics of Xiaohaizi Formation in Bashituo and Yasongdi Area,Bachu Uplift-maigaiti Slope of Tarim Basin

通过分析岩芯、薄片和测井资料,发现巴什托—亚松迪区块小海子组为典型的点滩相沉积,滩相主要为台缘滩和台内滩,其特有的滩相环境对后期的成岩演化起到决定性作用。该区域小海子组储集空间以粒间溶孔为主,伴生晶间孔,粒内溶孔。控制孔隙发育的成岩作用主要有胶结作用、溶蚀作用、白云岩化作用。胶结作用发生在成岩阶段的各个时期而阻碍了孔隙的发育,其中以第一期纤维状胶结与第二期粒状胶结为主。溶蚀作用与白云岩化作用相辅相成,共同促进孔隙空间的发育。其中白云岩化形成的晶间孔为部分滩相的暴露溶蚀提供了流体通道进而扩大了溶蚀孔洞空间。薄片和扫描电镜观察到小海子组颗粒灰岩伴生有萤石、重晶石等热液矿物以及大量孔隙中充填的地开石,证明小海子组滩相颗粒灰岩后期孔隙演化受到热液的影响。

By analyzing the drilling core,thin section and logging data,Xiaohaizi formation is the typical point beach facies reservior in Bashituo and Yasongdi area.The point beaches are mainly platform margin beaches and internal platform beaches.The unique beach facies play a decisive role in the diagenetic evolution.The reservior space of Xiaohaizi formation is mainly intergranular dissolution pores,accompanying with intercrystalline pores and intragranular dissolution pores.There are mainly cementation,dissolution and dolomitization in the diagenetic evolution.Cementation that appears mainly the first phase fibrous cement and the second phase granular cemente hinder the development of the pores in the various periods of diagenesis.Dissolution and dolomitization promote the development of pore space together.Intercrystalline pores forming by dolomitization provide the fluid channel for erosional dissolution of point beach,which enlarges the reservoir space.By analyzing thin section and scanning electron by microscope,Xiaohaizi formation granula limestone accompany hydrotherm mineral,such as fluorite and barite,at the same time,dickite silt so much pore,which can prove hydrotherm impact upon reservior space of Xiaohaizi formation granula limestone.