塔里木盆地古城地区下古生界碳酸盐岩成岩作用及储层孔隙特征

LOWER PALEOZOIC CARBONATE RESERVOIR DIAGENESES AND PORE CHARACTERISTICS IN GUCHENG AREA OF TARIM BASIN

以古城地区寒武系、中下奥陶统碳酸盐岩为主要研究对象,应用岩石普通薄片、铸体薄片、阴极发光和扫描电镜等实验分析技术,对研究区主要成岩作用类型及其对储层孔隙的影响进行研究。研究结果表明:古城地区主要的成岩作用有胶结、充填、硅化、压溶、溶蚀和白云石化作用,对于储层孔隙而言,胶结、充填、硅化和压溶作用是破坏性成岩作用,溶蚀和白云石化作用是建设性成岩作用,它们产生的溶孔、溶洞和裂缝是天然气的主要储集空间和运移通道。根据碳酸盐岩储层孔隙的特征,总结出古城地区储层发育灰岩溶蚀孔隙型、白云岩溶蚀孔隙型及白云岩溶蚀缝洞型3种孔隙类型。

Taking Cambrian and Middle-Lower Ordovician carbonate rocks in Gucheng area as the research objects,by means of ordinary thin section,cast section,cathode luminescence,SEM and other analyzing techniques,the main diageneses and their influences on the reservoir pores were studied. The achievements show that the principal diageneses are shown as follows: cementation,filling,silicification,presssolution,dissolution and dolomitization,for the pores,the former four actions are destructive to the diageneses,while the latter two are constructive,for the produced / secondary pores,caves and fissures are the main reservoir spaces and migration ways of the natural gas. According to the characteristics of the reservoir pores in the carbonate rocks,three kinds of the pore types are developed and summarized in Gucheng area: limestone dissolved pores,dolomite dissolved pores and dolomite dissolved caves-fissures.