南华北盆地鹿邑凹陷上古生界煤系地层砂岩储层特征  

Sandstone Reservoir Characteristics of the Upper Paleozoic Coal-bearing Strata in Luyi Sag,Southern North China Basin

作　　者：常海亮 杜春彦 张宏伟 王宏伟 祝朝辉 陈敬轶 CHANG Hailiang;DU Chunyan;ZHANG Hongwei;WANG Hongwei;ZHU Chaohui;CHEN Jingyi(Henan Provincial Land and Space Survey and Planning Institute,Zhengzhou,Henan 450053,China;Qinggong College,North China University of Science and Technology,Tangshan,Hebei 064000,China;College of Geosciences and Engineering,North China University of Water Resources and Electric Power,Zhengzhou,Henan 450046,China)

机构地区：[1]河南省国土空间调查规划院,河南郑州450053 [2]华北理工大学轻工学院,河北唐山064000 [3]华北水利水电大学地球科学与工程学院,河南郑州450046

出　　处：《现代地质》2024年第2期373-384,共12页Geoscience

基　　金：河南省财政地质勘查基金项目(豫国土资发[2016]46号,豫自然资发[2019]22号)。

摘　　要：鹿邑凹陷上古生界煤系砂岩储层特征认识不清,制约该区天然气藏相关研究和勘探部署。本文综合运用岩心观察、薄片鉴定、扫描电镜、压汞和声发射试验等分析方法查明砂岩储层特征,并阐释储层发育影响因素。结果表明,砂岩储层岩性以细-中粒、细粒岩屑石英砂岩为主,成岩作用类型多样,压实和胶结作用对储层破坏明显,溶解及破裂作用对储层贡献较大。储层属超低孔、超低渗的致密储层,储集空间类型以溶孔、晶间微孔、裂缝、少量剩余原生孔和铸模孔组合为主。孔隙结构分为3类,Ⅰ类的孔隙结构和物性最好,但发育规模小;Ⅱ类和Ⅲ类的发育规模大,但孔隙结构和物性差。储层发育受多种因素影响,构造背景决定其长期处于中-深埋藏环境;沉积微相控制其发育位置;压实作用导致储层原始孔隙度降低22.01%;多期次矿物胶结使储层更加致密化;含有机酸流体是促使不稳定组分溶解形成次生孔隙的主要因素;破裂作用极大程度地改善储层渗透性,但发育局限。该认识对煤系地层非常规天然气藏的研究具有促进作用,也可为鹿邑凹陷相关勘探工作的部署提供基础参考。Sandstone reservoir characteristics of the Upper Paleozoic coal-bearing strata in Luyi Sag are not yet clearly understood,and this hinders the relevant research and exploration deployment of natural gas in this area.In this study,we use analytical methods such as core observation,thin section identification,scanning electron microscopy,mercury intrusion testing,and acoustic emission testing to investigate the characteristics of sandstone reservoirs and further identify the factors affecting the reservoir development.The study results show that the sandstone reservoirs are dominated by fine and medium-grained and fine lithic quartz sandstone.There are various types of diagenesis,among which compaction and cementation are the ones mostly damaging the reservoirs,while dissolution and fracturing contribute more to the damaging.The reservoirs are tight ones with ultra-low porosity and ultra-low permeability,and the reservoir spaces are dominated by dissolved pores,intergranular micropores,fractures,with minor residual primary pores and mold pore.The reservoir pores can be divided into three categories based on the structures.Type I are good in structures and physical property,but with limited development;typeⅡand typeⅢare widely developed,but are poor in structures and physical properties.The reservoir development can be affected by many factors and the tectonic setting affecting the reservoirs are in a moderate-depth buried diagenetic environment for a long time;the sedimentary microfacies control its position of the development.The compaction reduces the primary porosity by 22.01%.The organic acid-bearing diagenetic fluids are the main factor promoting the dissolution of unstable components to form the secondary pores;fracturing greatly improves the reservoir permeability but its development scale is limited.This understanding is of great significance to the study of unconventional gas reservoirs in coal-bearing strata,and it provides a key reference for the deployment of relevant exploration in this area.

关 键 词：储层特征 致密化 主控因素 煤系地层 鹿邑凹陷 

分 类 号：P618.1[天文地球—矿床学] TE122.2[天文地球—地质学]