注CO_2置换煤层CH_4试验研究

利用屯留矿和寺河矿圆柱体原煤试样,进行不同注入压力条件下注CO2置换CH4试验,研究分析了置换过程中气体的吸附特性及注入压力对CO2置换效果的影响,提出了低孔隙压力条件时具有更好的置换效果。研究结果表明,同等条件下,置换平衡后煤体吸附CO2气体能力远强于CH4;煤体中CH4体积比随注入压力的降低而减小,而CO2体积比则呈现相反趋势;在8MPa围压条件下,随着注入压力的升高,CH4产出率呈线性关系降低,CO2置换比呈指数关系减小,显示出在试验压力范围内,低压条件下的CO2置换效果更佳;同等条件时,相对于试验中的无烟煤,贫瘦煤置换效果更好。

Experimental study on coal-bed methane displacement by carbon dioxide injection

This study used the cylinder raw coal samples from Tunliu coal mine and Sihe coal mine to carry out the displacement of CH₄ with CO₂ experiment under the different injection pressures. Analyzed the gas adsorption characteristics in the experiment and the influence of injection pressures on the replacement of with CO₂, and proposed that replacement effect was better at low pore pressure. The results are as follows. Adsorption capacity of CO₂ is stronger than that of CH₄ under the same condition in the process of displacement; CH₄ volume ratio decreases with injection pressure decreasing, while CO₂ volume ratio shows the opposite trend; When the confining pressure is 8 MPa, the CH₄ output ratio reduces with linear relation and the replacement ratio of CO₂ reduces with exponential relation as injection pressure increases, and indicating that the replacement is better at low injection pressure in this displacement experimental; The replacement effect of meager lean coal sample is better than anthracite under the same conditions in this experimental.