二氧化碳驱替煤层甲烷的试验研究

Study on test of displacement coal-bed methane by carbon dioxide

煤层甲烷的持续抽采会导致煤层甲烷压力的下降。向煤层中注入二氧化碳,可以提高煤层孔隙压力,驱替煤层甲烷。为研究二氧化碳驱替煤层甲烷的可行性,在实验室进行了二氧化碳驱替煤层甲烷的研究。通过研究发现,驱替排采的甲烷产出率明显优于自然排采。因此,可以采用二氧化碳驱替煤层甲烷的方法提高甲烷抽采率。驱替排采对完整煤样和破碎煤样甲烷产出效率的影响不同,破碎煤样的驱替速度较快,而完整煤样的驱替效率较高。因此,在利用二氧化碳驱替不同煤体的甲烷时,要选择合理的驱替方案。

The methane pressure will decline in coal seams,due to the duration extraction of methane.Injecting carbon dioxide in coal seams that can increase pore pressure and displace methane.The displacement experiments were performed in laboratory to investigate the feasibility of that injecting carbon dioxide to displace methane in coal seams.The experimental results showed that the displacement recovery is obviously better than conventional CBM recovery.Therefore,injecting carbon dioxide to displace methane can increase the efficiency of methane extraction.In addition,the effect of displacement recovery on the production of methane in intact and fractured specimens are different.The displacement rate was faster in fractured specimens.The displacement efficiency was higher in intact specimens.Therefore,when injecting carbon dioxide to displace methane in different type of coal seams,it was important to select the suitable injection schedule for displacement.