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火山岩优质储层包括火山机构等控制的原生孔隙和裂缝,以及风化作用和断裂控制的次生孔隙和裂缝,查清塔北地区二叠系火山岩优质储层的类型及物性的变化规律对指导该区勘探具有重要意义。在对野外露头及井下岩心进行观察和采样的基础上,通过薄片及铸体薄片观察、扫描电镜观察、常规物性测试、压汞法毛细管压力曲线分析等方法研究塔北地区二叠系火山岩的储层特征。研究发现塔北地区二叠系火山岩储层的储集空间可分为原生和次生2种:原生孔隙包括气孔、气孔杏仁构造等,原生的裂缝包括柱状节理、冷凝收缩缝和隐爆裂缝等;次生孔隙包括斑晶内溶孔、铸模孔、基质内溶孔和溶蚀缝。优质储层主要由次生孔隙和裂缝构成,孔隙度可高达15.05%,渗透率最高可达22×10-3μm2,剖面上火山岩储层物性由下到上逐渐变好,上部次生改造作用强烈,次生孔隙及裂缝更加发育,具有很好的勘探前景。
The volcanic rocks of high quality reservoirs include primary pores and fractures controlled by volcano bodies and secondary pores and fractures controlled by weathering and fracture control. The changes of types and physical properties of Permian volcanic reservoirs in Tarim Basin are investigated. Area exploration is of great significance. Based on the observation and sampling of the outcrop and core in the field, the reservoir of Permian volcanic rocks in the north of Tarim Basin was studied by the observation of lamellar and cast thin slices, scanning electron microscopy, conventional physical property test and capillary pressure curve analysis of mercury injection Layer characteristics. It is found that the reservoir space of the Permian volcanic reservoirs in Tarim Basin can be divided into two types, primary and secondary: primary pores including stomata and apical almond structures, and primary cracks including columnar joints, condensation and shrinkage cracks and implosion cracks Secondary pores include intra-plastid pores, mold holes, stroma dissolved pores and dissolution cracks. The high-quality reservoirs are mainly composed of secondary pores and fractures. The porosity is as high as 15.05% and the permeability is as high as 22 × 10-3μm2. The physical properties of volcanic reservoirs in the section gradually get better from bottom to top, , Secondary pores and cracks more developed, with good exploration prospects.