超临界CO2对烟煤Ⅰ型断裂韧性影响的实验研究
Experimental study on the effect of supercritical CO2 on bituminous coal type Ⅰ fracture toughness
孙泽东 1任泫琦2
作者信息
- 1. 山西大同大学煤炭工程学院,山西省大同市,037009;太原理工大学原位改性采矿省部共建教育部重点实验室,山西省太原市,030024
- 2. 山西大同大学煤炭工程学院,山西省大同市,037009
- 折叠
摘要
为探究超临界CO2 在强化开采煤层气(ScCO2-ECBM)过程中烟煤断裂力学的响应特征,对 3 种层理方向的烟煤试样开展超临界CO2(ScCO2)不同吸附时长条件下的三点弯曲实验、低温氮气吸附实验,研究 ScCO2 作用下烟煤 Ⅰ型断裂韧度及其孔隙结构的变化规律.研究结果表明,烟煤的 Ⅰ型断裂韧度随 ScCO2 吸附时长的增加持续劣化,当吸附时间延长至 30d时烟煤I型断裂韧度达到最低,且烟煤的断裂韧度大小为载荷正交层理型＞载荷垂直层理型＞载荷平行层理型.同时,随着吸附时间的增加,烟煤的比表面积和总孔体积的变化与断裂韧度基本一致,而平均孔径则呈相反趋势.这些微观结构的变化与其断裂韧性密切相关,从而造成烟煤的抗断裂能力弱化,研究结果可为预测 ScCO2-ECBM过程中煤储层物性变化及评价CO2 封存的稳定性提供理论指导.
Abstract
In order to study the response characteristics of bituminous coal fracture mechanics in the process of intensive coal bed methane extraction with supercritical CO2(SC CO2-ECBM),three-point bending experiments and low-temperature nitrogen adsorption experiments with different adsorption times of ScCO2 were carried out on bituminous coal samples with three kinds of bedding directions,and the change law of bituminous coal type Ⅰ fracture toughness and its pore structure under the action of ScCO2 were studied.The results showed that the type Ⅰ fracture toughness of bituminous coal deteriorated continuously with the increase of ScCO2 adsorption time,when the adsorption time was extended to 30 days,the type Ⅰ fracture toughness of bituminous coal reached the lowest point,and the fracture toughness of bituminous coal with different bedding directions from high to low is:load orthogonal bedding type,load vertical bedding type,load parallel bedding type.At the same time,with the increase of adsorption time,the changes of specific surface area and total pore volume of bituminous coal were basically consistent with the fracture toughness,but the average pore size showed the opposite trend.These microstructure changes were closely related to the fracture toughness,which led to the weakening of the fracture resistance of bituminous coal.The research results can provide theoretical guidance for predicting the change of coal reservoir physical properties in the ScCO2-ECBM process and evaluating the stability of CO2 storage.
关键词
ScCO2/烟煤/三点弯曲/断裂特性/层理方向/孔隙结构Key words
ScCO2/bituminous coal/three-point bending/fracture characteristics/bedding direction/pore structure引用本文复制引用
基金项目
山西省基础研究计划(自由探索类)青年项目基金资助项目(202303021212245)
出版年
2024
NETL
NSTL
万方数据