煤基质的气体膨胀特性与气体渗透性关系的研究

项目名称： 煤基质的气体膨胀特性与气体渗透性关系的研究

项目编号： No.21306218

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 化学工业

项目作者： 曲世杰

作者单位： 中国科学院山西煤炭化学研究所

项目金额： 25万元

中文摘要： 气体在煤基质中的渗透性是煤层气开采及CO2驱替煤层气开采过程模拟及预测的基础数据。气体吸脱附引起的煤层膨胀/收缩会降低/增加煤层渗透率。分别对应于煤体积变化或渗透性的研究较多，但直接关联两者的研究鲜有报道。另外，煤接触CO2后，其吸附性会发生变化。吸附性的改变势必会影响煤层的膨胀性，从而改变煤层的渗透性。本申请拟利用前期研发的设备，同时测定煤的吸附和膨胀数据，建立吸附量和膨胀量之间的关系；在无外加应力（避免应力对煤结构的影响）条件下，测定煤样的孔隙特征及气体渗透性，建立煤孔隙特征与渗透性之间的关系；基于煤样膨胀前后气体的吸附量、煤柱的膨胀量及孔隙特征的变化，研究CO2与煤接触对其吸附和膨胀的影响及膨胀引起的煤孔隙特征变化。研究变量包括温度、压力、煤种及气体种类，旨在建立膨胀量、渗透率变化量、孔隙率变化量的三参数数学模型，阐明气体吸附导致的膨胀对煤基质渗透性的影响规律。

中文关键词： 吸附；膨胀；渗透；超临界二氧化碳；扩散模型

英文摘要： The permeability of gas in the coal matrix is the basis data of simulating/predicting CBM/CO2-ECBM. The permeability change is generally considered to be caused by the gas sorption/desorption induced coal swelling/shrinking, which can narrow/widen the coalbed fractures. There are lots of studies about the swelling and permeability,respectively. However, the relationship of them is out of attention. Based on the previous research，after exposure to CO2, the adsorbed amount of coal samples increases, which will induce the swelling of coal seam. As a result, the permeability will change. In this application, the adsorbed amount of gas and the corresponding coal swelling ratio in different coal rank will be studied, in order to clarify the relationship between adsorbed amount and swelling ratio. The pore character (or adsorbed amount) and permeability will be measured at no confining stress，in order to find the quantitative mathematic expression. Based on the difference of permeability, adsorbed amount, swelling ratio and pore character before and after exposure to gas, the three parameter mathematic model will be developed. And an attempt will be made to clarify effect of interaction of coal with gas on change of permeability.

英文关键词： sorption；swell；permeability；supercritical CO2；diffusion model