Yidong Li , Jienan Pan , Haichao Wang , Zhenzhi Wang , Xianglong Wang , Meng Li , Yunbo Li
{"title":"用原子力显微镜测量 ScCO2 注入诱导的煤炭断裂面的微结构响应","authors":"Yidong Li , Jienan Pan , Haichao Wang , Zhenzhi Wang , Xianglong Wang , Meng Li , Yunbo Li","doi":"10.1016/j.jgsce.2024.205471","DOIUrl":null,"url":null,"abstract":"<div><div>Fractures in coal serve as the principal channels for the migration of coalbed methane (CBM). The microscopic traits of coal fracture surface are of significance for evaluating reservoir permeability and directly influence the outcome of CO<sub>2</sub> storage and displacement. To comprehend the impact of CO<sub>2</sub> on the coal fracture surface, the alterations in the coal fracture surface before and after CO<sub>2</sub> injection are investigated vis atomic force microscopy. As CO<sub>2</sub> gradually transforms into a supercritical state, the fracture density and aperture on the coal fracture surface gradually escalate. The mean pore size and porosity of the coal fracture surfaces rose from 5.45 nm to 6.55 nm and from 4.66% to 6.85%, respectively. The proportion of micropores (<2 nm) gradually diminished. The proportions of mesopores (2–50 nm) and macropores (>50 nm) proportions gradually. Swelling, extraction and mineral dissolution are the predominant reasons for the alteration in the pore structure of the coal fracture surface. CO<sub>2</sub> injection modifies the roughness and fractal characteristics of the coal fracture surface. The mean roughness <em>R</em><sub><em>a</em></sub> dropped from 6.54 nm to 4.03 nm, and the fractal dimension <em>D</em><sub><em>s</em></sub> declined from 2.45 to 2.28. With the fixed scanning range, the injection of CO<sub>2</sub> has been shown to reduce the roughness of coal fracture surface and lower their fractal dimension, thereby has a positive influencing permeability enhancement. Therefore, in CO<sub>2</sub>-ECBM engineering, it is essential not only to analyze the physical properties of the target reservoir, but also to conduct a comprehensive evaluation of permeability with a suitably defined area of the reservoir.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"131 ","pages":"Article 205471"},"PeriodicalIF":0.0000,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Microstructural response of coal fracture surface induced by ScCO2 injection measured with AFM\",\"authors\":\"Yidong Li , Jienan Pan , Haichao Wang , Zhenzhi Wang , Xianglong Wang , Meng Li , Yunbo Li\",\"doi\":\"10.1016/j.jgsce.2024.205471\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Fractures in coal serve as the principal channels for the migration of coalbed methane (CBM). The microscopic traits of coal fracture surface are of significance for evaluating reservoir permeability and directly influence the outcome of CO<sub>2</sub> storage and displacement. To comprehend the impact of CO<sub>2</sub> on the coal fracture surface, the alterations in the coal fracture surface before and after CO<sub>2</sub> injection are investigated vis atomic force microscopy. As CO<sub>2</sub> gradually transforms into a supercritical state, the fracture density and aperture on the coal fracture surface gradually escalate. The mean pore size and porosity of the coal fracture surfaces rose from 5.45 nm to 6.55 nm and from 4.66% to 6.85%, respectively. The proportion of micropores (<2 nm) gradually diminished. The proportions of mesopores (2–50 nm) and macropores (>50 nm) proportions gradually. Swelling, extraction and mineral dissolution are the predominant reasons for the alteration in the pore structure of the coal fracture surface. CO<sub>2</sub> injection modifies the roughness and fractal characteristics of the coal fracture surface. The mean roughness <em>R</em><sub><em>a</em></sub> dropped from 6.54 nm to 4.03 nm, and the fractal dimension <em>D</em><sub><em>s</em></sub> declined from 2.45 to 2.28. With the fixed scanning range, the injection of CO<sub>2</sub> has been shown to reduce the roughness of coal fracture surface and lower their fractal dimension, thereby has a positive influencing permeability enhancement. Therefore, in CO<sub>2</sub>-ECBM engineering, it is essential not only to analyze the physical properties of the target reservoir, but also to conduct a comprehensive evaluation of permeability with a suitably defined area of the reservoir.</div></div>\",\"PeriodicalId\":100568,\"journal\":{\"name\":\"Gas Science and Engineering\",\"volume\":\"131 \",\"pages\":\"Article 205471\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-10-18\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Gas Science and Engineering\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S294990892400267X\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"0\",\"JCRName\":\"ENERGY & FUELS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Gas Science and Engineering","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S294990892400267X","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"0","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
Microstructural response of coal fracture surface induced by ScCO2 injection measured with AFM
Fractures in coal serve as the principal channels for the migration of coalbed methane (CBM). The microscopic traits of coal fracture surface are of significance for evaluating reservoir permeability and directly influence the outcome of CO2 storage and displacement. To comprehend the impact of CO2 on the coal fracture surface, the alterations in the coal fracture surface before and after CO2 injection are investigated vis atomic force microscopy. As CO2 gradually transforms into a supercritical state, the fracture density and aperture on the coal fracture surface gradually escalate. The mean pore size and porosity of the coal fracture surfaces rose from 5.45 nm to 6.55 nm and from 4.66% to 6.85%, respectively. The proportion of micropores (<2 nm) gradually diminished. The proportions of mesopores (2–50 nm) and macropores (>50 nm) proportions gradually. Swelling, extraction and mineral dissolution are the predominant reasons for the alteration in the pore structure of the coal fracture surface. CO2 injection modifies the roughness and fractal characteristics of the coal fracture surface. The mean roughness Ra dropped from 6.54 nm to 4.03 nm, and the fractal dimension Ds declined from 2.45 to 2.28. With the fixed scanning range, the injection of CO2 has been shown to reduce the roughness of coal fracture surface and lower their fractal dimension, thereby has a positive influencing permeability enhancement. Therefore, in CO2-ECBM engineering, it is essential not only to analyze the physical properties of the target reservoir, but also to conduct a comprehensive evaluation of permeability with a suitably defined area of the reservoir.