Gravity Drainage in Thermally Stimulated Wells

Abstract

Abstract Continued interest in steam stimulation has led to the publication of a number of predictive techniques for this type of oil production. Most of these involve radial flow through a heated zone around the wellbore. Another possible producing mechanism is gravity drainage. This paper presents a method for calculating gravity drainage production rates as a function of time following steam injection. The heat transfer model accounts for cooling of the oil sand by both vertical and radial conduction. Heat losses for any number of productive sands separated by unproductive rock are calculated for the injection, shut-in and production phases. The oil flow rate from the heated region is calculated by the gravity drainage equations. Excellent agreement is shown between calculated and field results. In addition, the results of a number of process and reservoir variable studies are included.