CAJ | 학술논문

利用普通薄片、铸体薄片、扫描电镜等实验数据，结合测井资料，分析了渤海湾盆地歧北斜坡沙河街组储层岩石成分、孔渗分布、孔隙结构及储层品质指数（ RQI）等特征，探讨了储层形成机理。研究结果表明，沙河街组砂岩成熟度较低，孔隙类型多样，孔隙结构以Ⅳ类为主，孔喉为细－微孔小喉，以次生粒间孔为主，属于典型的低孔低渗储层。储层形成的主控因素有沉积作用、次生溶蚀作用及深部异常高压等。水道沉积环境控制储集岩的碎屑粒度、胶结物性质及含量、孔隙的孔喉半径和分选系数等，水道主体砂岩比侧缘砂体孔隙度高出3％～5％，且厚度较大，易形成良好的储集层。压实作用和胶结作用使原生孔隙消失殆尽，砂岩中长石等的溶蚀作用造成了次生孔隙的发育，为储集空间的主要贡献者。异常压力的发育抑制了压实作用，促进了溶蚀作用，起到了增加储层孔隙的作用。综合分析认为，重力流水道和扇三角洲前缘相带中的次生溶蚀发育带是储层发育的有利区带。
이용보통박편、주체박편、소묘전경등실험수거，결합측정자료，분석료발해만분지기북사파사하가조저층암석성분、공삼분포、공극결구급저층품질지수（ RQI）등특정，탐토료저층형성궤리。연구결과표명，사하가조사암성숙도교저，공극류형다양，공극결구이Ⅳ류위주，공후위세－미공소후，이차생립간공위주，속우전형적저공저삼저층。저층형성적주공인소유침적작용、차생용식작용급심부이상고압등。수도침적배경공제저집암적쇄설립도、효결물성질급함량、공극적공후반경화분선계수등，수도주체사암비측연사체공극도고출3％～5％，차후도교대，역형성량호적저집층。압실작용화효결작용사원생공극소실태진，사암중장석등적용식작용조성료차생공극적발육，위저집공간적주요공헌자。이상압력적발육억제료압실작용，촉진료용식작용，기도료증가저층공극적작용。종합분석인위，중력류수도화선삼각주전연상대중적차생용식발육대시저층발육적유리구대。
Experimental means , including ordinary slices , casting sections and electron microscope , were used to study samples from reservoirs in the Shahejie Formation of Qibei slope in Bohai Bay Basin .The results were then combined with logging data to analyze the features(lithological composition,porosity and permeability distribution,pore texture and re-servoir quality index ( RQI) ) and forming mechanism of the reservoirs .The analyses show that the sandstone reservoirs in the formation are typical low-porosity and low-permeability reservoirs featuring in low maturity ,various types of pores ,Ⅳtype of pore structure ,small-to micro-sized pore throat and secondary intergrannual pores .The forming mechanisms of the reservoirs include sedimentation ,secondary dissolution and deep overpressure .It also indicates that sedimentary setting of the channels controlled the particle size ,cement properties and content ,pore throat size and sorting coefficient of the re-servoirs.Sandstone in the main channels offered better conditions for the forming of reservoirs as it is thicker and has a porosity of 3%-5%higher than that at the side edges .Primary pores in the reservoirs were almost killed during compac-tion and cementation , while dissolution of feldspar and other minerals created secondary pores and provided reservoir space .Overpressure in the reservoirs restrained compaction but boosted dissolution and enlarged reservoiring space .A comprehensive analysis of all the information suggests that secondary pore zones in gravity flow channels and fan delta fronts be the most favorable locations for reservoirs to develop .