Calculation of the Production Rate of a Thermally Stimulated Well

Abstract

This paper presents a method for calculating the producing rate of a well as a function of time following steam stimulation. The calculations have proved valuable in both selecting wells for stimulation alld ill determining optimum treatment sizes. The heat transfer model accounts for cooling of the oil sand by both vertical alld radial conduction. Heat losses for any number of productive sands separated by unproductive rock are calculated for the injection. shut-in and production phases of the cycle. The oil rate increase caused by viscosity reduction due to heating is calculated by steady-state radial flow equations. The response of Sllccessive cycles of steam injection call also he calculated with this method.Excellent agreement is shown betweell calculated and actual field results. Also included are the results of several reservoir and process variable studies. The method is best suited for wells producing from a multiplicity of thin sands where the bulk of the stimulated production comes from the unheated reservoir. The flow equations used neglect gravity drainage and sall/ration changes within the heated region.

Upscaling for Thermal Recovery

“…The frontal advance models (Marx and Langenheim, 1959;Boberg and Lantz, 1966;Mandl and Volek, 1969;Gajdica et al 1993;Jankovic, 1993) assume a horizontal frontal displacement with the steam zone assumed to grow horizontally and the tendency for steam fingers to go beyond the condensation front is suppressed by condensation. The main disadvantages of these models are that they are single-phase and one dimensional, and do not allow gravity override.…”

Heavy and Thermal Oil Recovery Production Mechanisms

“…Heat Remaining in the Reservoir Boberg and Lantz (1966) give the average temperature of the steam zone, T avg , as…”

“…For all following cycles, the initial amount of energy is calculated based on steam zone volume and the average temperature at the end of the previous cycle. The average temperature at any time during the cycle is calculated using Eq.11 (Boberg and Lantz, 1966). Since Boberg and Lantz's equation assumes a cylindrical shape for the heated zone, this equation is just an approximation for the triangular shape being considered.…”

An Analytical Model for Simulating Heavy-Oil Recovery by Cyclic Steam Injection Using Horizontal Wells, SUPRI TR-118

“…Further, the reservoir simulator is sensitive to data that are often not known or unreliable. It is natural to develop simpler analytical models (Boberg and Lantz, 1966) that account for the important mechanisms involved in this process, and from which we may draw general conclusions about performance. This indeed has been the cas,e and several models and correlations of varying degree of complexity are available in the literature for cyclic operation of vertical wells and continuous steam injection in dual horizontal wells (Butler et al, 1980).…”