Dryness Changes of Wellbore in Viscous Crude Oil Production with Nitrogen Injection

In the process of steam injection,the steam flows along the wellbore.The heat transfer process includes heat conduction,heat convection and radiation.With the knowledge of the heat transfer,fluid mechanics and thermodynamics,this paper analyzes the heat transfer process of wellbore,establishes the mathematical model of heat transfer with consideration of the borehole stress changes and calculates the heat loss of wellbore.Then dryness changes at each point of wellbore can be calculated.It studies the dryness' changes with variations of depth in the undersea steam well to provide reference for the on-site technologic design of steam injection system.