A Calculation Model for Wellbore Heat Loss and Pressure Drop Considering Steam Phase State Changing in Superheated Steam Injection Well

Based on the mass and momentum conservation equations of wellbore fluid and the energy conservation equations of fluid and formation,a calculation model considering the steam phase state changing from single phase flow to gas-liquid two phase flow of non-isothermal wellbore heat loss and pressure drop is established,by which the hydrodynamic phenomena and the heat transform in the superheated steam injection well are described.The hydrodynamic and thermal on-way parameters during superheated and wet steam injection are analyzed,and the sensitivity studies of the steam sand-face thermal parameters are conducted.The simulation results show that the pressure drop and temperature drop of the superheated steam injection are greater than those of wet steam injection,but the steam quality drop is smaller so that more quantity of heat can arrive the well bottom;the increase of the wellhead overheated temperature is favorable for the increase of the well bottom stream quality;as the injection pressure increases,the steam quality of well bottom may decrease;as the steam injection rate increases,the steam pressure and heat loss rate of well bottom may gradually decrease,and the temperature and the steam quality may gradually increase.