Abstract
Recently, more and more attention has been paid to the development of deep-water gas wells around the world. However, hydrate formation in string has always affected the safety of deepwater gas well production and there is no accurate risk prediction method currently.
In this study, a more optimized and practical prediction model for hydrate formation region (HFR) was established. The model has been applied to deepwater gas wells and the influence of typical factors on HFR is analyzed. The conclusions are as follows: (a) the gas temperature decreases gradually from bottom hole to wellhead, and the rate of decline is obviously faster near mud line. (b) under low gas recovery rate, the effect of heat transfer on gas temperature reduction is more obvious, but at high gas recovery rate, the opposite is true. (c) because of the pressure change in wellbore, the hydrate equilibrium temperature gradually decreases with the decrease of well depth and HFR often appears in the upper half of wellbore. (d) the increase of gas production and formation temperature is helpful to shorten the length of HFR in the string, which is due to the increase of gas production and reservoir temperature increases the temperature distribution in the pipe string. (e) the hydrate equilibrium temperature and HFR decrease by increasing inhibitor content. Increasing the use of hydrate inhibitors is the most practical and effective measure to reduce hydrate risk.
In the production process of deepwater gas wells, the effective location of HFR is very important to the production safety of deepwater gas wells. This research can be helpful to the research of wellbore flow assurance during the production of deep-water gas wells.
