基于等温吸附线的煤层气储层的测井评价技术

Logging evaluation methods of coal-bed methane reservoirs based on adsorption equation

煤层气以吸附状态赋存在煤层中而有别于常规天然气,导致传统评价常规天然气储层的方法不再适于评价煤层.煤层气含量的计算是煤层评价中最重要的一个环节,总结对比前人应用地球物理技术评价煤层气含量各种方法得出,兰格缪尔等温吸附法是计算煤层气最合适的方法,因此被广泛应用到煤层气的评价中.一般的兰格缪尔等温吸附方程都是由某一温度下甲烷的等温吸附试验数据,得出适用于该温度条件下甲烷的等温吸附方程,而不能预测其它温度.本文针对烟煤和无烟煤提出了适于不同温度条件的等温吸附方程,此外还重点论述了在无煤心实验数据情况下的煤质测井分析方法.

Coal-bed methane is much different from conventional natural gas because of its absorpted condition. So the conventional method is not suitable for coal evaluation of this kind. The calculation of coal-bed methane content is an important aspect in the coal evaluation. Compare and summary of all the previous methods for calculating coal-bed methane content using geophysical technology, suggest that the Langmuir adsorption method is the most suitable method which has been widely applied to the evaluation of coalbed methane. The general Langmuir adsorption equation is obtained from adsorption test data under a particular temperature of methane that yields the adsorption equation under this temperature, which can not predict the other temperature. In this paper, we propose the temperature adsorption equation suitable for bituminous and anthracite coal. And we also focus on the coal quality analysis using logging data when there is no experimental data.