摘要
鄂尔多斯盆地盒8段致密砂岩气是国内典型的致密气勘探领域,为了明确盒8段致密砂岩气储层微观特征及其形成机理,开展了相关研究。在钻井岩心观察的基础上,进行了铸体薄片、场发射扫描电镜、CT扫描及恒速压汞等多种实验,研究认为盒8段致密砂岩类型以石英砂岩、岩屑石英砂岩为主,总体特征表现为中—粗粒、分选中等,颗粒以棱角状、次棱角状为主,颗粒间以点、线接触为主,填隙物种类多样。储层储集空间类型主要包括残余粒间孔隙、溶蚀孔隙、微纳米孔隙及裂缝等,微纳米孔隙占储层孔隙90%以上;喉道类型包括缩颈型、弯曲片状及管束状等,孔喉特征总体表现为喉道细、连通性好—中等,平均喉道半径与渗透率的相关性最好。沉积作用和沉积组构控制了储层原始物性差异,辫状河心滩砂体和三角洲分流河道砂体物性比冲积扇扇中水道砂体物性好,后期经历的强压实作用是储层致密的主控因素,胶结作用加剧了对储层孔隙结构的破坏,而普遍、强烈的溶蚀作用在一定程度上改善了致密储层的储集性能。
The He 8th member in the Ordos Basin is a typical field explored for tight sandstone gas.Studies have been carried out to figure out the microscopic characteristics and forming mechanisms of the tight sandstone gas reservoir.After observation of cores,a variety of experiments were carried out,such as cast thin sections,field emission scanning electron microscope,CT scanning and constant-rate mercury injection.It is concluded that the tight sandstones in the He 8th member are quartz sandstone and lithic quartz sandstone,which are moderate to coarse,moderately sorted,angular and subangular,point or line contact among grains and filled with various cements.The reservoir space is composed of residual intergranular pores,dissolution pores,micro-and nano-pores and fractures,and micro-and nan-pores contribute over 90%to the reservoir porosity.Throats are contracted necks,curved sheets and tubes.They are thin and commonly connected.The average throat radius is well correlated to permeability.Sedimentation and sedimentary structure control the difference in original reservoir physical properties.The central sandstone in the braided river and the delta distributary channel have better physical properties than those of the channel sandstone in the alluvial fan.Late strong compaction tightened the reservoir,cementation damaged the pore structures,and strong dissolution improved the reservoir properties to some extent.
作者
张春林
李剑
刘锐娥
Zhang Chunlin;Li Jian;Liu Ruie(PetroChina Research Institute o f Petroleum Exploration&Development;CNPC Key Laboratory o f Gas Reservoir Formation and Development)
出处
《中国石油勘探》
CAS
CSCD
北大核心
2019年第4期476-484,共9页
China Petroleum Exploration
基金
国家科技重大专项“大气田富集规律与勘探关键技术”(2016ZX05007-002)、“中国大型气田形成条件、富集规律及目标评价”(2011ZX05007)
关键词
鄂尔多斯盆地
盒8段
致密砂岩气
微观特征
形成机理
Ordos Basin
He 8th member
tight sandstone gas
microscopic characteristic
forming mechanism
