辽河坳陷西部凹陷南段古近系沙河街组致密砂岩特征与成因机制  

Characteristics and forming mechanism of tight sandstones in the Paleogene Shahejie Formation of southern West Sag,Liaohe Depression

作　　者：孟元林[1] 王志轩[1] 张凤莲[2] 孟凡晋 焦金鹤[1] 施立冬 

机构地区：[1]东北石油大学地球科学学院,黑龙江大庆163318 [2]中国石油辽河油田勘探开发研究院,辽宁盘锦124010 [3]Resolution Energy Services, Houston TX 77002, USA

出　　处：《古地理学报》2016年第4期569-580,共12页Journal of Palaeogeography：Chinese Edition

基　　金：国家自然科学联合基金项目(批准号:U1262106);国家自然科学基金项目(批准号:41572135);国土资源部示范工程项目(编号:1211302108019-2)资助~~

摘　　要：渤海湾盆地辽河坳陷西部凹陷南段古近系沙河街组中发现了低产油气流和工业油气流,储集层具有低—特低孔隙度、特低—超低渗透率、低压的特征,属于典型的致密砂岩储集层。应用大量的薄片、扫描电镜、粒度分析、压汞和物性等测试资料,研究了致密砂岩的微观特征,探讨了致密砂岩的形成机理。研究结果表明,致密砂岩(孔隙度小于10.0%)大多发育在凹陷区;矿物成分、粒度、分选、磨圆等沉积学参数与致密砂岩的形成关系不大;致密砂岩的孔隙类型主要为次生孔隙,孔隙结构整体上具有中孔径、微细喉以及喉道分选不均匀等特征;机械压实作用和胶结作用导致了致密砂岩的形成,该致密砂岩属于次生型致密砂岩。Low-yield and commercial oil flows have been discovered in the Paleogene Shahejie For-mation,southern West Sag,Liaohe Depression,Bohai Bay Basin.The reservoirs are typical tight sand-stone reservoirs characterized by low-ultralow porosity,extra-low-ultralow permeability and low pressure. Based on data of thin sections,SEM,grain size,mercury pressure analysis and physical property,the micro-characteristics and formation mechanisms of tight sandstones were analysed.The results show that：The tight reservoirs （with porosity value lower than 1 0%） are mainly distributed in the sag area;The for-mation of tight reservoirs are not controlled by factors such as mineral composition,grain size,grain sor-ting and roundness;Pore types mainly consist of secondary pores and pore structures are characterized by medium pore diameter, tiny throat and heterogeneous throat sorting; The tight sandstones are mainly formed through compactions and cementations and are thus categorized as diagenetic tight sandstones.

关 键 词：致密砂岩 非常规油气 成因机制 西部凹陷 辽河坳陷 古近系 

分 类 号：TE122.221[石油与天然气工程—油气勘探]