鄂尔多斯盆地华庆长63储层微观孔喉结构特征及其对水驱油效率的影响

Microscopic pore-throat structure characteristic and its influence on oil displacement efficiency in Chang-63 reservoir of Huaqing area inOrdos Basin

应用常规压汞、扫描电镜、铸体薄片、砂岩微观模型水驱油等多种实验,讨论了鄂尔多斯盆地华庆地区长63储层微观孔喉结构特征及其对驱油效率的影响,结果表明,长63储层的储集空间主要为粒间孔,其次是溶蚀孔。应用纳米CT技术将储层的喉道分为点状喉道、缩颈喉道、片状喉道以及筛管状喉道四类;根据常规压汞实验和毛管压力曲线将研究区储层的微观孔喉结构分为Ⅰ类、Ⅱ类、Ⅲ类、Ⅳ类四种类型,这四种类型的储层对应的驱油效率和驱油路径有明显差异;与孔隙度相比,渗透率对驱油效率的影响更明显。

Through experiments on conventional mercury injection,scanning electron microscope,casting thin slice and water drive displacement test with real microscopic sandstone models,the characteristic of the microscopic pore-throat structure and its influence on the oil displacement efficiency were discussed.The results indicate the primary pore of the reservoir space is inter-granular pore and the secondary pore is dissolved pore.By applying NM-CT technology,the reservoir throats can be divided into four types:dotting throat,necking shape throat,flaky throat and sieve-tube throat.Based on conventional mercury injection and the capillary pressure curve,the pore structure can be divided into four types,namely type-I,type-II,type-III and typeIV.Different pore structures correspond to different Oil displacement efficiency and the displacement path.Permeabilityeffect on oil displacement efficiency is bigger than that of the porosity.