低渗透储层微观孔隙结构研究——以华庆地区长6_3为例

Study on micro-pore structure characteristics in Low permeability sandstone reservoir——A case of Chang 6_3 in Huaqing Area

鄂尔多斯盆地华庆地区长63储层绝大部分为低渗-特低渗储层,物性差,非均质性强,研究其微观孔隙结构有利于充分认识储层特征、了解渗流规律进而提高采收率。利用扫描电镜、铸体薄片、高压压汞实验等对长63储层的岩石学特征、物性特征、微观孔隙结构进行研究。结果表明研究区目的层受成岩作用影响较大,微观孔隙结构复杂多变;据压汞资料Ⅰ类孔喉排驱压力低,孔喉分布集中、分选中等,属于研究区储集性能和渗流能力最好的储层类型,Ⅱ类所占比例最大。

Reservoirs of Chang 6_3 in Huaqing of Ordos Basin,are mostly low and extra- low permeability. It is characterized by strong heterogeneity、poor physical property. Studing the microscopic pore structure is conducive to realize reservoir characteristics sufficiently and understand permeability law to improve oil recovery. Scanning electron microscope,casting thin sections,high- pressure mercury injection experiment was used to study petrologic characteristics,physical characteristics,microscopic pore structure on 6_3 reservoir. Experimental results showed that the diagenesis had enormous implications in the study area,and the microscopic pore structure types of reservoir are complex. First type of sandstone pore- throat structure have lower displacement pressure,the distribution of it is concentrated and its separation is medium,which belongs to the best type of reservoir on the reservoir properties and the flow capability in the study area,second kind of sandstone pore- throat structure have the largest proportion.