摘要
在岩心观察的基础上,结合常规、铸体薄片、扫描电镜、压汞和核磁共振等资料对鄂尔多斯盆地合水地区延长组长7段致密油储层岩石学、物性特征及孔隙结构特征进行了研究.结果表明合水地区长7油层组致密油储层储集空间以溶蚀孔隙和微孔隙为主,原生孔隙保留较少,孔喉连通性较差,总体表现为物性差和孔隙结构复杂的特征.储层经历较强的压实作用,胶结物类型主要为碳酸盐和粘土矿物,此外还发育较强的溶蚀作用.根据压汞曲线形态与压汞参数,结合核磁共振T_2谱特征,将长7致密油储层孔隙结构类型划分为四类.并分别阐明了压实作用、胶结作用、溶蚀作用及其微孔隙含量对不同类型孔隙结构的影响,并运用综合考虑了压实、胶结成岩作用以及微孔隙含量的成岩综合系数来阐明并定量表示成岩过程中多种成岩作用对孔隙结构改造的综合效应.成岩综合系数与T_2几何平均值具有良好的统计正相关关系,因此可以作为不同类型孔隙结构定量表征的理想参数.经过对影响孔隙结构特征的成岩作用类型和强度的深入剖析,可在成因机理分析的基础上通过成岩综合系数来实现储集岩孔隙结构的定量评价.同时通过T_2几何平均值可以反推储层在成岩演化阶段所经历的成岩作用类型及强度,进而实现储层精细评价.
The petrology,reservoir properties and pore structure characteristics of Chang 7 tight oil reservoirs in Heshui area of the Ordos Basin were studied by means of core observation,conventional thin section,casting thin section,scanning electron microscope,mercury intrusion tests and nuclear magnetic resonance（ NMR） measurements. The pore structure of Chang 7 tight oil reservoir is divided into four types according to the characteristics of mercury intrusion curves and mercury injection parameters as well as T2 spectrum from NMR measurements. Firstly,the influence of compaction,cementation,dissolution and micropore content on the pore structure of the reservoir is expounded qualitatively. The comprehensive effects of diagenesis on the pore structure are reflected and quantified by using the comprehensive coefficient of diagenesis（ Cg） considering compaction, cementation and micropore content. The comprehensive coefficient of diagenesis has a good statistical correlation with T2 geometric mean（ T2 gm）,therefore it can be used as an ideal parameter for quantitative characterization of various types of pore structures. Based on the analysis of the types and degrees of diagenesis,the quantitative evaluation of pore structure of reservoir rocks can be realized by the comprehensive coefficient of diagenesis on the basis of analysis of the genesis mechanism.
出处
《地球物理学进展》
CSCD
北大核心
2017年第3期1095-1105,共11页
Progress in Geophysics
基金
国家自然科学基金"致密砂岩储层成岩相测井识别评价方法研究"(41472115)资助
关键词
成岩作用
孔隙结构
长7油层组
合水地区
diagenesis
pore structure
Chang 7 tight oil reservoir
Heshui area
