四川盆地宣汉—达州地区下沙溪庙段储层特征研究

RESERVOIR CHARACTERISTICS OF LOWER SHAXIMIAO FORMATION IN Xuanhan-Dazhou AREA,SICHUAN BASIN

通过岩心、普通薄片及铸体薄片的观察、物性分析、X-衍射等分析手段,对四川盆地宣汉—达州地区下沙溪庙段的储层特征进行了研究。结果表明,研究区下沙溪庙段储层孔隙类型以残余原生粒间孔和粒间溶孔为主,次为粒内溶孔,发育少量粒缘缝、微裂缝,储层喉道几何形态主要为缩颈喉道、片状喉道、管束状喉道。平均孔隙度为2.27%,平均渗透率为0.21mD,整体以"低孔-低渗"为特征;储层的孔隙度与渗透率基本呈指数正相关关系,孔-渗相关性较好。

In this study,the reservoir characteristics of Lower Shaximiao Formation in Xuanhan-Dazhou area,Sichuan Basin,are studied based on core observation,thin-section analysis and X-refraction of casting thin-section.Results show that :(1) pore types mainly include residual primary intergranular pore and intergranular dissolution pore,second for intragranular dissolution pore,with a little grain edge fracture and microfracture;(2) for throat,its geometry is mainly necking,sheetlike and tube-bundle throats;(3) this reservoir is characterized by low porosity and low permeability,average porosity of 2.27% and average permeability of 0.21mD and(3) there is roughly a positive and better correlation between porosity and permeability.