摘要
煤的孔隙率是表征煤储层瓦斯富集程度的重要指标,对煤层气资源的开发至关重要。为了提高煤层气的开采和利用,且更好地研究煤储层的孔隙率。采用河南焦作古汉山矿原煤标准煤样,将煤样加工为平行于面割理、垂直于面割理和垂直于层理共3个方向,采用河南理工大学瓦斯地质研究所自制煤储层压裂模拟及物性特征实验系统,对每组煤样同步进行超声波特征和应力—应变测试实验,将所测得的品质因子、孔隙率和轴压进行两两拟合,并对其结果进行讨论。结果表明:在保持围压不变的情况下,煤样的孔隙率随轴压的增大呈线性趋势减小,并且不同方向的孔隙率压力影响系数表现出明显的各向异性;超声波在煤样中传播时,品质因子随轴压的增大而增大,且能量衰减有明显的层理效应;随着加载过程中轴压的增大,品质因子与孔隙率满足较好的线性关系,为利用纵波品质因子预测煤层的孔隙率提供了有效依据。
The porosity of coal is an important index to indicate the degree of gas enrichment in coal reservoir and is very important to the development of coal bed methane resources.In order to improve the exploitation and utilization of coal bed methane and better study the porosity of coal reservoir,this article uses the Gu⁃hanshan mineral raw coal sample as standard coal,which was processed into three types:parallel to face cleat,perpendicular to the plane of cleat and perpendicular to the bedding three directions.Using coal reservoir fractur⁃ing simulation experiment and physical property simulation system made by the Institute of Gas Geology of Henan Polytechnic University,synchronous analysis of ultrasound characteristics and stress-strain test of each group of coal sample was performed.The measured quality factor,porosity and axial pressure are in dual fit and the results are discussed.The results show that the porosity of coal sample decreases linearly with the increase of axial pressure,and the influence coefficients of porosity pressure in different directions show obvious anisotro⁃py.When the ultrasonic wave propagates in the coal sample,the quality factor increases with the increase of axi⁃al pressure,and the energy attenuation has obvious stratification effect.With the increase of axial pressure in the loading process,the quality factor and porosity satisfy a good linear relationship,which provides an effective ba⁃sis for using longitudinal wave quality factor to predict the porosity of coal seam.
作者
张凯
李东会
梁雁侠
ZHANG Kai;LI Dong-hui;LIANG Yan-xia(College of Safety Science and Engineering,Henan Polytechnic University,Jiaozuo 454000,China;State Key Laboratory Cultivation Base for Gas Geology and Gas Control,Henan Polytechnic University,Jiaozuo 454000,China)
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2020年第8期1092-1098,共7页
Natural Gas Geoscience
基金
河南联合国家自然科学基金项目(编号:U1704129)
河南省自然科学基金项目(编号:182300410138)
河南省博士后经费项目(编号:19030070)联合资助.
关键词
孔隙率
品质因子
轴压
线性拟合
影响系数
Porosity
The quality factor
Axial compression
Linear fitting
Influence coefficient
