摘要
基于Langmuir等温吸附方程式,开展不同煤阶不同温压条件下等温吸附模拟实验,实验结果表明：在煤岩镜质组反射率Ro〈3.0%时,Langmuir等温吸附曲线随煤阶、温度、压力升高表现出明显的分带性。随着煤阶的升高,煤吸附能力逐渐增强。温度小于55℃时不同煤阶Langmuir体积受温度影响较小,之后影响逐渐增大。低煤阶在12 MPa、中高煤阶在15 MPa以前随压力增加Langmuir体积增大明显。根据实测含气量外推法结合高温高压等温吸附实验建立了深煤层含气量数学模型,显示煤层含气量随埋深呈现快速增加—缓慢增加—不增加—缓慢减小的变化规律,其中低煤阶临界深度介于1400~1700 m,中高煤阶临界深度介于1500~1800 m。该含气量数学模型对预测深部煤层含气量变化规律及煤层气资源评价提供基础依据。
Based on Langmuir isothermal adsorption equation, we carried out isothermal adsorption simulation experiments under hightemperatures and high pressures for different coal ranks. The results show that when vitrinite reflectance Ro less than 3.0%, the curvesof Langmuir isothermal equation appear in a zone with the rising coal rank, temperature, and pressure. The adsorption capacity isenhanced with the rising coal ranks. The Langmuir volume of different coal ranks was less affected when the temperature was lowerthan 55℃, while more for temperatures above 55℃. The Langmuir volume increased obviously with the rising pressures when the lowrank coal under 12 MPa and mid-high rank coal below 15 MPa. We established a mathematical model for determining gas content ofdeep coalbed based on the measured gas content extrapolation method and the high temperature and high pressure isothermaladsorption experiments. The modeled gas content shows variable outcomes, i.e., fast increase, slow increase, no increase, and slowdecrease with the buried depth. The critical depth of low rank coal is located between 1400 m to 1700 m while the mid-high rank coalis located between 1500 m and 1800 m. The mathematical model of gas content provides a basis for forecasting gas content andevaluating deep coalbed methane resources.
出处
《高校地质学报》
CAS
CSCD
北大核心
2015年第2期274-279,共6页
Geological Journal of China Universities
基金
国家重大科技专项(2011ZX05033-003)
国土资源部油气资源战略研究中(1A14YQKYQ0126)联合资助
关键词
不同煤阶
深煤层
含气量
数学模型
临界深度
different coal ranks
deep coalbed
gas content
mathematical model
critical depth
