哈日凹陷巴音戈壁组碎屑岩储层及微观孔喉特征

(1.西安科技大学 地质与环境学院,陕西 西安 710054; 2.陕西延长石油(集团)油气勘探公司,陕西 延安 716000; 3.中煤科工集团西安研究院有限公司,陕西 西安 710054)

碎屑岩; 储层特征; 微观结构; 哈日凹陷; 银额盆地

Clastic reservoir and micro-pore-throat characteristics of Bayinggobi Formation in Hari sag
ZHENG Li-wei1,2,DONG Shu-ning1,3,TANG Sheng-li1,WANG Dong-hui2,WANG Zhi-wei2,CHANG Zhi-ren2,CAI Qin-qin2

(1.College of Geology and Environment,Xi'an University of Science and Technology,Xi'an 710054,China; 2.Yanchang Petroleum Group Exploration Company,Yan'an 716000,China; 3.Xi'an Research Institute of China Coal Technology & Engineering Group Corp,Xi'an 710054,China)

clastic rock; reservoir characteristics; microstructure; Hari sag; Yin'gen-Ejinaqi Basin

备注

通过对银根-额济纳旗盆地哈日凹陷巴音戈壁组13块岩心样品的恒速压汞测试,结合扫描电镜观测、显微组分鉴定,对储层岩石学特征、孔隙发育情况及微观孔喉特征进行了研究。结果 表明,岩石以粉砂质泥岩、岩屑石英砂岩为主,孔隙主要发育晶间孔、粒间缝、粒间溶孔和粒内溶孔,孔隙度在0.1%~3.4%之间,渗透率在0.004~1.327×10-3 μm2之间。孔喉主要为片状和弯片状吼道,喉道普遍狭窄,孔喉大小分布不集中,半径分布在0.004~0.066 μm之间,连通性差,储层最大孔喉半径、平均孔喉半径与孔隙度、渗透率之间具有较好的相关性。毛细管压力曲线特征为中排驱压力-微细喉道型和高排驱压力型-微喉道型,特低渗透碎屑岩储层孔隙结构具有孔喉连通性差及孔喉性质差异大的特点,哈日凹陷巴音戈壁组特低渗透碎屑岩储层性质主要由喉道控制,喉道控制储层渗透性,进而决定开发难度和开发效果。

The petrological characteristics of reservoir,pore development and microscopic pore throat characteristics were studied,based on the testing of 13 core samples by constant-rate mercury penetration technique of Bayingebi Formation in Hari sag of Yingen-Ejinaqi Basin,combining with scanning electron microscope observation and maceral identification.The studies show that the rocks are mainly silty mudstone and lithic quartz sandstone; the pores are mainly intergranular pore,intergranular seam,interparticle dissolution pore and intragranular dissolved pore; porosity is between 0.1% and 3.4%,permeability between 0.004 and 1.327×10-3μm2.The radius of the pore throat is between 0.004~0.066 μ m,which is mainly flaky and curved flaky.The throat is generally narrow,the size distribution of the pore throat is not concentrated,and the connectivity is poor.The capillary pressure curve is characterized by mid row displacement pressure minuteness throat type and high displacement pressure micro throat type.The maximum pore throat radius,average pore throat radius are well related with the porosity and permeability.And the pore structure of ultra-low permeability clastic rock reservoir is characterized by poor connectivity of pore throat and great difference of pore throat properties,and the characteristics of ultra-low permeability clastic rock reservoir of Bayingebi formation in Hari sag are mainly controlled by the throat.The throat determines reservoir permeability,and then exerts an influence the development.