Abstract:

The production mode adopted by Dongsheng gas field is “downhole throttling and low pressure gathering and transportation”. In order to meet the production needs, some gas wells need wellhead throttling to control production. However, wellhead throttling is easy to generate hydrate on the ground. So it is necessary to increase the wellbore and surface fluid temperature before throttling. Therefore, downhole vacuum insulated tubing test was carried out in the target block of Dongsheng gas field. According to the test results, the data fitting was carried out by using the software—Pipesim—to verify the application effect of insulated tubing in gas field, and its application situation is predicted and analyzed. The test results showed that, the vacuum insulated tubing could obviously increase the fluid temperature of the wellhead, and prevent the hydrate formation in wellhead pipeline, so that to realize energy saving and consumption reduction to some extent. The fitting results of the field data also showed that the heat transfer coefficient of downhole vacuum insulated tubing was significantly lower than that of the common tubing. According to the application analysis, and considering the cost and the characteristics of low pressure gathering and transportation, it is concluded that there are certain limitations in the application of this technology in the low-pressure gas field. But it could be used as an alternative process of gas field if the wellhead throttling production must be adopted.

Key words: Dongsheng gas field, vacuum insulated tubing, wellbore heat preservation, wellhead throttling, prediction of production in station