摘要
页岩气吸附影响因素及机理分析是其能高效开发的基础理论问题。通过页岩样品对甲烷的容量法等温吸附实验,获取它们在不同压力、温度、样品粒径和含水条件下的一系列等温吸附曲线,分析了曲线特征以及吸附规律与Langmuir吸附定律的符合程度,并对吸附曲线弯折的现象进行了讨论。研究发现:低有机碳含量的页岩对甲烷的等温吸附曲线与标准的Ⅰ型等温线有差别,其吸附规律与Langmuir方程符合程度较低,不同温度和不同粒径下的等温吸附曲线与Ⅰ型等温线的差异大小不明显,但湿样的表现比较突出,会出现负吸附;低有机碳含量的页岩对甲烷的等温吸附曲线多在甲烷临界压力前后似有弯折,近于两段式的表现。推测发生此现象的原因为实验误差、页岩的非均质和吸附过程中基质膨胀以及吸附相的存在。
The analysis of influence factors and mechanism of shale gas adsorption is a basic theory about high efficiency development of shale gas. In this paper, based on volumetric methane adsorption isotherm experiments,using selected shale samples, a series of adsorption isotherms under different temperature, pressure,particle size,moisture were obtained on different samples. The characteristics of the adsorption isotherms were analyzed and the adsorption rules were compared to the Langmuir equation. And the phenomenon and mechanism about bending of methane adsorption isotherm for shale were analyzed particularly. The findings indicate that, for low TOC shale,there were differences between the obtained adsorption isotherms and standard type I IUPAC adsorption isotherms,and the adsorption was not in accordance with the Langmuir equation absolutely. At different temperature and particle size of shale sample, differences between the isotherms and standard type I adsorption isotherms were absolute. The sample moisture has an enormous effect on adsorption capacity of shale to methane. The bending of adsorption isotherms for shale to methane may occur while pressure was at critical pressure of methane or so. The reasons for this may be experimental error, heterogeneity of shale, matrix swelling and the absence of adsorption phase.
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2015年第3期580-591,共12页
Natural Gas Geoscience
基金
国家自然科学基金项目(编号:51374172)
中国石油科技创新基金项目(编号:2012D-5006-0203)
陕西省教育厅科研计划项目(编号:14JK1583)联合资助
