HOT FLUID INJECTION INTO HEAVY OIL RESERVOIRS INTERCEPTED BY A STATIONARY VERTICAL FRACTURE

An analytical and a numerical model for the injection of hot fluid into stationary vertical fractures are developed. For both models, the fracture is assumed to have infinite conductivity and fully penetrate the reservoir thickness. The conductive heat flux in the overburden and underburden is considered one dimensional and symmetric with respect to the reservoir.; The analytical model solves the energy equation in an infinite system with constant properties of the system and zero thermal conductivity in the reservoir. Fluid flow in the reservoir is considered elliptical which is physically more sound than the linear models described in the literature. The obtained solution for the temperature distribution is used to develop expressions for the thermal efficiency and oil rate and recovery. Although limited in scope because of necessary restrictive assumptions, these expressions have proved useful in the preliminary analyses of hot fluid injection projects.; The numerical model involves the simultaneous solution of mass and energy balances for an oil-water system in two dimensions. The model utilizes the IMPES method of solution and suggests a new procedure for eliminating the saturations from the mass and energy balance equations. This procedure is direct and requires much less computational work than Gaussian elimination used by previous investigators. The relative permeabilities and enthalpies at the grid boundaries are shifted upstream in order to avoid possible oscillations in the solutions.; Previous numerical models of the injection of hot fluid into vertically fractured systems have exclusively dealt with the elastic behavior of the reservoir rock during fracturing. Uniqueness this model stems from its concern with the petroleum engineering aspects of the process. The primary objective of this study is to (i) present a detailed description in the numerical and analytical models, (ii) analyze pressure response in the fracture and temperature distribution in the reservoir, (iii) study effects of injection conditions and fluid and reservoir characteristics on the performance of hot water injection, including oil recovery and thermal efficiency, and (iv) examine the analytical solution for a practical range of injection temperature, oil viscosity and reservoir permeability.