鄂尔多斯盆地志靖-安塞地区延长组长10储层特征及主控因素分析

Characteristics and its main controlling factors of Chang 10 reservoir in Yanchang formation in Zhijing-Ansai area,Ordos basin

针对鄂尔多斯盆地志靖-安塞地区长10砂岩储层油气勘探开发的问题,通过岩心、薄片鉴定、扫描电镜、X-衍射等资料对研究区长10砂岩储层的岩石学特征、成岩作用、孔隙类型、物性特征以及主控因素进行详细的分析。结果表明:长10砂岩储层以中粒长石砂岩为主、岩屑质长石砂岩次之,成熟度较低;储集空间类型主要为残余粒间孔、长石溶孔和浊沸石溶孔,孔隙度和渗透率平均值较低,分别为11.4%和2.35mD,且部分地区具有典型致密砂岩储层特征;储集物性受多种因素控制,其中物源是物质基础,沉积相带是环境基础,强烈压实作用和胶结作用导致孔隙大量损失,而溶蚀作用使得储层物性大大改善;东部较西部具有优越的物质基础,受来自长9烃源岩层更多酸性物质的影响,导致东部溶蚀作用较强,物性条件比西部要好。

In view of the problem of oil and gas exploration and development of Chang 10 reservoir in Yanchang formation in Zhijing-Ansai area,Ordos basin,using comprehensive methods such as cores,thin section analysis,SEM and X-ray diffraction analysis,the petrologic features,diagenesis,pore types,physical characteristics and the controlling factors of the Chang 10 Reservoir in the study area are analyzed in detail.The results show that the reservoir is mainly medium-granular arkose,secondly is lithic feldspathic sandstones with lower mineral maturity.The reservoir space type is mainly composed of residual intergranular pore,feldspar dissolved pore and laumontite solution pore.The average porosity is 11.4%,the average permeability is 2.35 mD,and some areas have typical tight sandstone reservoir characteristics.Reservoir properties are controlled by many factors,which the provenances supply and sedimentary environment are the foundation.Strong compaction and cementation are main causes leading to the physical property of the reservoir becoming poor,and the dissolution makes the reservoir physical property largely improved.The east side has a better material base compared with the west（the content of feldspar and laumontite is higher）,the east side is also influenced by more acidic material from Chang 9 hydrocarbon source rocks,which results in strong dissolution makes the reservoir physical property is much better than that in the west.