摘要
查明碳酸溶液与伊利石矿物(煤层主要黏土矿物之一)的反应特征,能够为煤层气井注CO2提高采收率(ECBM)工艺泵注参数优化及储层物性变化分析提供理论依据。为此,以沁水盆地潞安矿区余吾、常村矿煤样为例,测试了煤样中黏土矿物的含量,进行了25℃、35℃、45℃条件下,单一伊利石矿物与不同酸度碳酸溶液的反应实验;应用分光光度计、X射线衍射仪、能谱仪测试分析了反应液中Si、Al元素含量和反应前后伊利石结构与元素变化的情况,得出了Si元素溶出的反应动力学模型,并求取了Si元素溶出的表观活化能。实验结果表明:1当溶液pH值和反应时间相同时,Si元素的溶出量随温度的升高而增大,而Al元素的溶出量变化却很小;2当溶液pH值和温度相同时,随反应时间增加,Si元素含量呈先增加后减小的趋势,并有一定的振荡,且温度越高,Si元素达到溶出最大值的时间越短,而Al元素溶出速率较快,迅速达到溶出平衡;3Si元素的溶出符合扩散控制的界面反应模型,pH值越低,Si元素越易于溶出,表观活化能越小;4由于碳酸酸性较弱,伊利石与其反应后,晶体结构未发生明显的破坏。
The characteristics of reaction between illites （one of the major clay minerals in coal seams） and carbonic acid solution can provide a theoretical basis for optimizing the CO2 injection parameters of enhanced-CBM-recovery wells and analyzing the variations of coal reservoir quality. Taking the coal samples from Yuwu and Changcun Mines in the Lu＇an Mining Area of the Qinshui Basin as examples, we tested the content of clay minerals, performed experiments on reactions between illites and carbonic acid solution with different acidities at 25, 35 and 45 ℃ respectively. Moreover, we also analyzed the content of Si and A1 elements in the reaction solu- tion and the changes in the structure and elements of illites before and after the reaction by applying spectrophotometer, X-ray dif fraction, energy dispersive, built a kinetic model for the Si element dissolved in the reaction solution, and obtained the apparent acti- vation energy of the dissolution of Si under different pH conditions. The following conclusions were obtained. （1） When the pH values and reaction stages are the same, the dissolution rate of Si element increases along with the increase of temperatures, while that of A1 changes insignificantly. （2） When the pH values and temperatures are the same, the Si content in the reaction solution increa- ses first and then decreases with the reaction time, and shows some oscillation. Moreover, the higher the reaction temperature, the less time needed for the Si element to reach the maximum dissolution rate. In contrast, the dissolution rate of A1 is relatively large and the disso lution balance can be achieved rapidly. （3） The dissolution of Si is in accordance with the diffusiowcontrolled interface reaction model. The lower the pH is, the easier the dissolution of Si and the smaller the apparent activation energy of Si will be. （4） As the acidity of carbonic acid is weak, the crystalline structure of illites shows no significant damages after its reaction with the carbonic acid solution.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2014年第8期20-26,共7页
Natural Gas Industry
基金
国家科技重大专项课题"大型油气田及煤层气开发"(编号:2011ZX05042-003)
河南省瓦斯地质与瓦斯治理重点实验室--省部共建国家重点实验室培育基地开放课题(编号:WS2013B06)
关键词
伊利石
碳酸
硅元素
铝元素
溶解
反应动力学
CO2泵注
界面反应模型
表观活化能
illite, carbonic acid, silicon, aluminum elements, dissolution, reaction kinetics, pump injection of CO2, interface reaction model, apparent activation energy
