鄂尔多斯盆地北部下二叠统山西组2段储层特征及影响因素——以东胜气田A井区为例  

Reservoir characteristics and influencing factors of Lower Permian Shan-2 Member,northern Ordos Basin:A case study of Wellblock A in Dongsheng gas field

作　　者：王琼[1] WANG Qiong(Exploration and Development Research Institute,Sinopec North China E&P Company,Zhengzhou,Henan 450006,China)

机构地区：[1]中国石化华北油气分公司勘探开发研究院,河南郑州450006

出　　处：《天然气勘探与开发》2024年第3期23-31,共9页Natural Gas Exploration and Development

基　　金：中国石化华北石油局科研攻关项目(编号:P23030)。

摘　　要：为了进一步明确鄂尔多斯盆地北部东胜气田A井区二叠系下统山西组2段储层特征及影响因素,采用粒度分析、薄片鉴定、压汞试验、物性测试等技术手段及方法,对储层的岩石学及物性特征、储集空间类型与孔隙结构特征进行定性和定量分析,并从沉积作用和成岩作用两个方面探讨影响储层物性的主要因素。研究结果表明:①A井区山西组2段为辫状河三角洲平原沉积,储集层岩性为中—粗粒岩屑石英砂岩和石英砂岩,填隙物为泥质杂基和胶结物,主要发育碳酸盐胶结、黏土矿物胶结和硅质胶结。②储层属于特低孔隙、特低渗透率型,孔隙类型以粒间溶孔、粒内溶孔为主,伴有少量剩余粒间孔和微裂缝;孔隙以细孔为主,喉道主要为中—小喉,孔喉组合关系为细孔-中小喉。③储层物性受沉积作用和成岩作用双重控制,储层物性与岩石粒度呈显著正相关,位于分流河道上的心滩为最有利沉积微相。④破坏性成岩作用(机械压实和胶结作用)是降低储层孔隙度的主要因素,建设性成岩作用(溶蚀作用和裂缝作用)则可显著改善砂岩的孔渗性能。In order to identify the reservoir characteristics and influencing factors of the second member of Lower Permian Shanxi Formation(referred to as Shan-2 Member)in Wellblock A of Dongsheng gas field,northern Ordos Basin,the petrological and physical characteristics,reservoir spaces and pore structure properties are qualitatively and quantitatively analyzed by means of grain size analysis,thin section identification,mercury injection test,and physical property testing.The main factors affecting reservoir physical properties are discussed from the aspects of sedimentation and diagenesis.The results are obtained as follows.(i)The Shan-2 Member in Wellblock A belongs to the deposition of braid river delta plain.The reservoir rocks are composed of medium-to coarse-grained lithic quartz sandstones and quartz sandstones,with the interstitial materials of argillaceous hybrid matrices and cements(carbonate cements,clay mineral cements,and siliceous cements).(ii)The reservoir features ultra-low porosity and permeability,with the pore types comprising mainly intergranular and intragranular dissolved pores,as well as a few of residual intergranular pores and microfractures.The pores and the throats are dominated by micropores and small-medium throats,respectively,resulting in a pore-throat combination of micropores and small-medium throats.(iii)The reservoir physical properties are jointly controlled by sedimentation and diagenesis.There presents a significant positive correlation between the reservoir physical properties and rock grain size.The mid-channel bar located in the distributary channel is the most favorable sedimentary microfacies.(iv)Destructive diagenesis(i.e.mechanical compaction and cementation)is the major factor reducing the porosity of reservoir,while constructive diagenesis(i.e.dissolution and fracture)significantly improves the porosity and permeability of sandstone.

关 键 词：鄂尔多斯盆地 东胜气田 早二叠世 山西组 储层特征 沉积作用 成岩作用 

分 类 号：P618.13[天文地球—矿床学]