鸡西盆地煤储层吸附孔特征及分形表征研究  

Study on characterization and fractal features of adsorption pores of coal reservoirs in Jixi Basin

作　　者：黄赞 孙斌[2] 杨青[2] 马施民[1] 邵延文 田文广[2] 祁灵 黄雷 HUANG Zan;SUN Bin;YANG Qing;MA Shiming;SHAO Yanwen;TIAN Wenguang;QI Ling;HUANG Lei(School of Resource and Safety Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;Department of Unconventionals,Research Institute of Petroleum Exploration and Development,Petro China,Langfang 065000,China;Tianjin Branch,CNOOC(China)Co.,Ltd.,Tianjin 300457,China)

机构地区：[1]中国矿业大学(北京)地球科学与测绘工程学院,北京100083 [2]中国石油勘探开发研究院非常规研究所,河北廊坊065000 [3]中海石油(中国)有限公司天津分公司,天津300457

出　　处：《煤炭科学技术》2021年第5期218-226,共9页Coal Science and Technology

基　　金：国家科技重大专项资助项目(2016ZX05041-004)。

摘　　要：为研究有利于煤层气勘探开发的煤储层孔隙结构特征,采集8个具代表性的鸡西盆地不同矿区煤岩样品进行了工业分析和低温液氮吸附试验。基于低温液氮吸附数据,采用分形几何学原理及方法定量表征了鸡西盆地煤储层吸附孔孔隙结构特征。运用Frenkel-Halsey-Hill(FHH)模型计算了吸附孔分形维数D_(1)(相对压力为0~0.5)和D_(2)(相对压力为0.5~1.0),并探讨了分形维数与孔隙结构、物质组成以及煤变质程度的关系。研究结果表明:研究区煤岩样品吸附孔的孔隙形态主要包括半封闭的狭缝形孔、开放性较好的平行板状孔以及墨水瓶或细颈瓶形孔3种类型。较小相对压力阶段分形维数D_(1)变化范围1.38~2.74,平均为2.32,较大相对压力阶段分形维数D_(2)变化2.30~2.84,平均为2.59。其中,D_(1)表征煤吸附孔表面粗糙程度而D_(2)表征吸附孔结构的不规则性,D_(1)越高,孔比表面积越大;D_(2)越高,平均孔径越小,微孔含量越高,孔隙内部非均质性越强。不同吸附回线类型的煤样分形维数D_(1)呈现出Ⅲ类>Ⅱ类>Ⅰ类的规律,D_(2)则呈现出Ⅲ类>Ⅰ类>Ⅱ类的规律,D_(1)与水分、灰分以及镜质组含量均呈多项式分布,而D_(2)与水分及镜质组含量呈现负相关关系,与灰分关系不明显。D_(1)和D_(2)与镜质体反射率R_(o)关系均不明显。In order to investigate coal reservoir pore structure characteristics which is favor of coalbed methane exploration and develop⁃ment,we collected 8 kinds of coal from different coal mine areas in Jixi Basin,based on low temperature nitrogen adsorption experiment,we used the nitrogen adsorption fractal geometry analysis method to quantitatively characterize the coal reservoir adsorptive pore structural fea⁃tures in Jixi Basin.The adsorptive pore fractal dimensions D_(1)(relative pressure 0~0.5)and D_(2)(relative pressure 0.5~1.0)were obtained from the nitrogen adsorption isotherm using the FHH equation discussed relationship between fractal dimension and pore structure,material composition,as well as the degree of coal metamorphism.Results showed that pore morphology in the study area can be partitioned into 3 types,mainly including slit shaped pores,better openness parallel plate-like pores and ink bottle or narrow neck shaped pores.Fractal di⁃mensions D_(1) was 1.38~2.74 and the average fractal dimensions D_(1) was 2.32;fractal dimensions D_(2) was 2.30~2.84 and the average fractal dimensions D_(2) was 2.59.D_(1) representing the surface roughness of adsorption pores and D_(2) the irregularity of the pore structures.As D_(1) gets bigger,the pore specific surface area increases,whereas the bigger D_(2) gets,the smaller the average pore size becomes,the higher the micro⁃pore content is,and the larger the pore heterogeneity is.Pore fractal dimension D_(1) of coal samples with different adsorption and desorption curve types presents a pattern of typeⅢ>typeⅡ>typeⅠ,while D_(2) presents a pattern of typeⅢ>typeⅠ>typeⅡ.Between D_(1) and mois⁃ture,ash yield,vitrinite content all present polynomial distribution,but between D_(2) and moisture content,vitrinite content present linear negative correlation,correlation with coal R_(o) is not apparent.

关 键 词：鸡西盆地 低温液氮吸附 孔隙特征 分形维数 

分 类 号：P618.13[天文地球—矿床学]