A method for analyzing the pressure drop of Maoming subsea pipeline during pressure test

As a key acceptance link before pipeline commissioning, pressure test for subsea pipeline is the focus for owners and construction companies. There is a large temperature difference between surface water and bottom water in the deepwater of the South China Sea, so the pressure holding state required in the standard and specification cannot be reached until the heat exchange between the medium inside the pipeline and the environment around the pipeline is completed. And consequently, the pressure test lasts a very long time, and the engineering cost and commissioning date are impacted greatly. Therefore, it is necessary to develop a new analysis method, which can prove the pipeline safe and stabe, eliminate the pipeline quality problems and satisfy the commissioning conditions within the stipulated duration. In this paper, Maoming subsea pipeline project was taken as the example. The pressure drop was technologically simulated and calculated by analyzing the field data in detail. And a rapid acceptance method combining theory with practice was adopted to prove that the pressure drop fluctuation of Maoming subsea pipeline project during pressure test is reasonable, safe and reliable, the test time is shortened and the project is put into operation on time. In addition, the reasons for the fluctuation of pressure drop during the pressure test were analyzed. The research results provide a certain reference for the pressure test of deepwater subsea pipelines.