This paper describes the development of a fully implicit two-dimensional three-phase numerical simulator for steamflood. The model consists of three phase mass conservation equations for oil, steam and water, an energy conservation equation phase equilibrium equations and constrain equations
• It takes into account the effects of gravity, capillary force and formation dip, as well as the changes of three phase relative permeabilities with temperature and the heat losses to adjacent strata.
The model solves three-phase mass conservation equations and an energy conservation equation simultaneously. All terms in the equations are implicit with respect to time. The resulted Non-linear fully implicit finite difference equations system is solved using Newton-Raphson iterative method. The time step is automatically selected, its size is controlled by maximum specified changes and maximum practical changes of primary variables in each time step.
Based upon the geological characteristics of Jinglou anticline structure of Nanyang oilfield, Henan Province, the effect of formation thickness on steamflood performance is investigated in detail by using this simulator. The best range of formation thickness of heavy oil reservoir suitable for steamflood is obtained. The results will be useful to steamflood project design in this and other oil fields.