| Abstract |
The problems of steam (steam-water) production from hydrothermal reservoir and cold water injection into vapour-saturated reservoir are considered. The mathematical model includes equations of mass and energy conservation laws, the generalized Darcy law and thermodynamic relations. The formulation of each problem contains moving boundary at which the water saturation function suffers a discontinuity. The universal relations at discontinuity in combination with the thermodynamic equilibrium condition constitute the complete set of boundary conditions at the moving boundary. The analytical (linear approach) solutions of the one-dimensional problems for half space domain are presented. It is how (production problem) that the introduction of an evaporation surface separating the steam and water leads to superheating of the water in a zone ahead of the front. This contradiction is removed by introducing of an extended phase transition zone between the single - phase zones. Furthemore, the boiling front separating the water zone and the two-phase zone is degenerated. In this case condition of continuity of water saturation function is satisfied. Finally, this function at the mixture - steam front varies discontinuously from the unknown value to zero. The analytical solution of condensation process is derived for cold water injection into vapour - saturated reservoir. |