Due to its advantages such as safety and explosion protection, intelligence fiber optic sensors based on fiber optic interferometers are increasingly being applied in fields such as oil pipeline monitoring. In order to achieve the purpose of verifying the application of fiber optic interferometer sensors in fields such as oil pipeline monitoring, the author used the common fiber optic sensors of Michelson interferometer, combined with phase generation carrier demodulation algorithm for data processing, to conduct on-site monitoring of natural gas pipelines. However, we have found that in oil pipelines, due to the presence of some significant high-frequency noise interference, the interference and the frequency of the carrier and signal are mixed with each other, sometimes causing the phase generation carrier demodulation algorithm to malfunction. In response to this issue, the paper conducted theoretical analysis and simulation verification, and obtained the limitations of the phase generated carrier demodulation algorithm on high-frequency noise, laying the foundation for the future application of fiber optic interferometer sensors based on the phase generated carrier demodulation algorithm in gas pipeline monitoring.