基于恒速压汞技术研究页岩气储层孔隙结构:以湘西北地区五峰组页岩为例  

Pore Structure of Shale Gas Reservoirs Revealed by Constant-Speed Mercury Injection Experiments:A Case Study of Wufeng Formation Shale from Northwestern Hunan Province

作　　者：王静 郗兆栋[2] 陆冬华 WANG Jing;XI Zhaodong;LU Donghua(National Key Laboratory of Remote Sensing Information and Imagery Analyzing Technology,Beijing Research Institute of Uranium Geology,Beijing 100029;School of Energy Resources,China University of Geosciences(Beijing),Beijing 100083)

机构地区：[1]核工业北京地质研究院遥感信息与图像分析技术国家级重点实验室,北京100029 [2]中国地质大学(北京)能源学院,北京100083

出　　处：《地质与勘探》2021年第2期450-456,共7页Geology and Exploration

基　　金：中国博士后科学基金面上项目(编号:2019M660737)资助。

摘　　要：页岩气储层孔隙结构是页岩气富集成藏、储层评价和优选有利区的关键参数,区分孔隙和喉道是表征页岩气储层孔隙结构的关键。本文选择4块具有不同渗透率的湘西北地区奥陶系五峰组页岩为研究对象,基于恒速压汞实验讨论孔隙和喉道的大小、分布特征及其相互关系以及与渗透率的联系。结果表明:具有不同渗透率的页岩样品表现为较为相近的孔径分布特征但差异较大的喉道分布特征。页岩样品渗透率的大小与孔隙半径没有明显相关关系;喉道大小及其分布特征是控制低渗储层孔隙结构的关键要素之一。渗透率较低页岩样品的喉道以喉道半径小且集中分布为特征,而渗透率较大页岩样品的喉道以喉道半径大呈分散分布但主要以大喉道为特征。喉道特征是研究页岩气储层储集空间和吸附能力的重要部分,在以后对页岩气的勘探开发中应特别注意及重视。Pore structure is an essential parameter in optimizing favorable shale gas areas,and is an important standard in evaluation of reservoirs and shale gas accumulation.Constant-speed mercury injection experiments can distinguish pore and throat,quantitatively analyze parameters such as pore,throat and their ratios,and estimate capillary pressure of pore and throat,respectively,so as to characterize shale gas reservoirs.Four Wufeng shale samples from northwestern Hunan Province with different permeability have been measured by constant-speed mercury injection experiments.The results show that these shale samples have similar pore size distribution characteristics but different throat distribution features.The permeability and the average pore size have no obvious correlation,and the size of distribution of throat is the key factor controlling the permeability of shale reservoirs.The lower the permeability is,the more concentrated the throat distribution is,and the smaller the throat is.With the increase of permeability,the throat size gradually increases,and its distribution range becomes wider,and the proportion of large throat gradually increases.Throat characteristics are an important part of the study on the storage capacity and adsorption capacity of shale gas reservoirs,which should receive much attention in the future exploration and development of shale gas.

关 键 词：恒速压汞 喉道特征 孔隙特征 孔喉比 五峰组 湘西北 

分 类 号：TE311.2[石油与天然气工程—油气田开发工程]