塔东地区寒武系碳酸盐岩成岩作用及储层成因机理

通过岩心观察和薄片鉴定,结合阴极发光实验等方法,研究塔东地区寒武系碳酸盐岩成岩作用及储层形成机理。结果表明:研究区寒武系碳酸盐岩沉积后经历了多种成岩作用的改造,既有对储层孔隙发育具有建设性的(白云化作用、溶蚀作用和破裂作用等),又有破坏性的(压实作用、压溶作用、重结晶作用、硅化作用、黄铁矿化作用等)。储层储集空间主要有晶间孔和晶间溶孔、溶蚀孔洞和未充填裂缝空间;储层类型主要有白云岩溶蚀孔隙型和白云岩溶蚀缝孔洞型两类。白云化作用为储层发育提供了基础条件;后期热液溶蚀作用对于储层发育起关键性作用;晚期由于构造破裂作用对于改善储层的储渗性能具有重要意义。白云岩较为发育的斜坡和台地相区与断裂的叠合区域,热液溶蚀和构造破裂更加发育,是研究区寒武系碳酸盐岩优质储层发育的有利区带。

The carbonate diagensis and formation mechanism of the reservoir of Cambrian in east Tarim Basin

The study of the diagenesis and reservoir formation mechanism of carbonate rocks from the Cambrain in Eastern Tarim Basin was based on some data from core analysis, thin-section identification and cathodoluminescence experiments. The result shows that there were obvious diagenetic effects after sedimentation, some had constructive effects to the reservoir, such as dolomitization, dissolution and disruption. Some,as for compaction,pressolution,recrystallization and sillication were destructive to the reservoir in the study area. It also shows that the main reservoir spaces were intergranular pores, intergranular dissolution pores, dissolved pores and fractures which were not filled. The main reservoir types were dolomite dissolution pores and dolomite dissolution fracture pores. Dolomitization provided the basic condition to the reservoir, the late hydrothermal solution was crucial to the reservoir and the disruption later improved the permeability of the reservoir. Dolomite was more enriched in the area which slope and platform superposed with fractures. In this area hydrothermal solution and structural fracture were more developed thus make it the favorable zone of study area.