文昌A凹陷10区珠海组低渗储层孔喉结构特征

Characterization of pore-throat structure in low-permeability reservoir from Zhuhai formation of 10 area in Wenchang A sag

文昌A 凹陷10区珠海组以低渗储层为主,部分为中渗特征,储层低渗透、非均质性强是制约研究区增储上产的关键问题.利用铸体薄片、扫描电镜观察、常规压汞、恒速压汞和核磁共振等方法,分析储层渗流能力的微观孔喉结构及影响因素,精细表征其储层孔喉结构,定量评价孔喉结构的差异性.结果表明：文昌10区为原、次生共存的孔隙组合特征,孔隙半径主要分布在90. 0 -160.0μm之间,喉道半径分布在1. 0 -6. 0μm之间,孔喉结构表现为中-大孔、细-较细喉特征,不同粒级储层物性主要取决于喉道半径;储层类型以Ⅱ、Ⅲ类储层为主,部分为Ⅰ2 类.储集岩粒度与压实作用是研究区孔喉结构主要影响因素,次为胶结作用和自生黏土.该结果为研究区天然气勘探开发提供储层综合评价的地质依据.

The reservoir from Zhuhai formation of 10 zone in Wenchang A sag are characterized by lowpermeability,partly moderate permeability and strong heterogeneity which is the key to constraint increasing reserves and production.To find out micro pore-throat characteristics and its influencing factors which decide reservoir percolation ability.Fine characterization of pore-throat structure and quantitative evaluation of the difference of pore and throat structure was studied by cast liquid photos,scanning electron microscope observation,conventional mercury injection the constant-rate mercury injection experiment and NMR analysis.The result shows that the pore is characterized by primary and secondary pore coexistence.Pore radius mainly lies between 90~160μm,throat radius mainly lies between 1~6μm;pore-throat structure is characterized by mesopore,macropore,fine throat.The reservoir of different particle sizes is good or does not mainly depend on the size of throat radius and the reservoir is characterized by Ⅱ,Ⅲtypes mainly andⅠ2partly.It is approved that the grain size and compaction strength are the main factors on influencing pore-throat structure,secondly cementation and authigenic clay.The research of pore-throat structure is the great significance to gas exploration and development.