Rapid determination of ethylene glycol content in the produced water of coalbed methane wells by gas chromatography-mass spectrometry

In the process of gas field exploitation in cold regions, the formation of gas hydrate in the gas collection pipeline has always been a great technical difficulty. In order to effectively prevent the formation of gas hydrates in the gas collection pipeline, ethylene glycol is mainly injected into the pipeline as an inhibitor. In order to ensure the normal production of oil and gas wells and the optimal use of ethylene glycol, it is necessary to monitor the changes of ethylene glycol in the production process in real time. Due to the advantages of gas chromatography-mass spectrometry (GC-MS) such as separation efficiency and detection sensitivity, the content of ethylene glycol in the produced water of coalbed methane wells was tested by this method. The results showed that the precision of ethylene glycol samples with different concentrations prepared from produced water was 0.7%~2.1%, and the recovery rate was in the range of 98.5%~101.2%, which proved that the precision, repeatability and spike recovery rate of GC-MS were good, meeting the requirements of analysis and determination. The method and test conditions are used to detect the content of ethylene glycol in the produced water of YI3 well in Hancheng coalbed methane field. The results show that the method is simple, rapid and accurate, and can be used for real-time monitoring of the content of ethylene glycol in the produced water of a gas well.