Research On Precipitation Law And Liquid Loading Risk Of Condensate Water In Dongfang 13-1 HTHP Gas Reservoir

The Dongfang 13-1 gas reservoir is a typical HTHP gas reservoir.As the gas reservoir temperature is high,the mutual ability of hydrocarbon fluid and formation water is strong and the water vapor content in natural gas is higher than that of ordinary.In the development of such gas reservoirs,with the temperature and pressure changes,the water vapor in natural gas may be precipitated.Whether the condensate occurs in the reservoir or the wellbore will affect the development of gas reservoir.This paper studies from experiment for the situation that precipitation law of condensate water is unclear and the risk analysis of liquid loading is insufficient.After the study of critical liquid carrying flow and gas well productivity,the risk of liquid loading was analyzed.Through the study,the paper has got the following achievements:(1)On the basis of the research,an experimental scheme suitable for the study of condensate precipitation law in HTHP gas reservoirs was designed and the experiment was carried out.The experimental results show that the moisture content of natural gas increases with the decrease of pressure and the increase of temperature.The water vapor in natural gas does not precipitate in the reservoir but will precipitate in the wellbore.(2)Through the nuclear magnetic resonance experiments,the source of output water was analyzed.The experimental results show that the amount of bound water that has been released due to expansion is minimal.When the reservoir pressure is reduced,the bound water will enter the natural gas in the form of water vapor,which in turn increases the moisture content of the natural gas.(3)After considering the wellbore trajectory,the distribution of temperature and pressure and the change of interfacial tension,the critical liquid carrying flow calculation model is established.It is found that the critical fluid flow in the gas wells is a dynamic change,which is related to the temperature,pressure,water gas ratio,gas well structure,tubing size,working system and so on.We should be based on the specific situation of gas reservoirs and wells to calculate the critical carrying flow.(4)Overall,for the Dongfang 13-1 gas reservoir,in the case of the produced fluid is mainly condensed water,gas wells have a lower risk of liquid loading.Taking a reasonable working system can avoid it.