Steamflooding in heavy oil reservoirs is one of the principal thermal oil recovery methods. This paper evaluates principal thermal oil recovery methods. This paper evaluates the existing analytical steamflood models with respect to their mechanisms and predictive capabilities and compares them with field data. The three steamflood models selected were: a frontal advance model [Jones (1981)], a modified frontal advance model [Farouq Ali (1982)], and a vertical gravity override model [Miller and Leung (1985)]. Each model was somewhat modified to improve its ability for the prediction of production rate and/or history match of typical field production rate and/or history match of typical field production data. production data. The Jones steamdrive model, with its empirically determined scaling factors, was found to give a reasonable history match of oil production for the Kern River field. Fields with different characteristics will require an adjustment of these scaling factors and/or field property data to achieve an acceptable history match. The modified Farouq Ali steamdrive model gives a good history match without need for empirical factors or adjustable parameters. It is thus recommended for the prediction of steamdrive oil recovery when field production data are unavailable. The Miller-Leung gravity override steamflood model, which contains two adjustable parameters, was found to possess the best overall history matching Capabilities and is recommended for this purpose. purpose.
The injection of steam into heavy or pressure depleted oil reservoirs has been a successful enhanced oil recovery process for more than three decades. A principal application process for more than three decades. A principal application of the steam injection is steamflooding which is also termed steam drive or steam displacement. In this process, steam is continuously injected into a number of injection wells, and the displaced fluids are produced from the production wells. Ideally, the injected steam forms a steam saturation zone around the vicinity of the injection well. The temperature in the steam zone is nearly equal to that of the injected steam. Moving away from the injection well, the steam temperature drops gradually as the steam expands in response to the pressure drop and heat losses to base formations. At a certain pressure drop and heat losses to base formations. At a certain distance, the steam condenses and forms a hot-oil bank. In the steam zone, oil is displaced by the steam. In the hot oil zone several changes take place which result in oil recovery. They include heat losses the formation, thermal expansion of the oil, and reduction of oil viscosity. In addition, residual saturation may decrease and changes in relative permeability may occur due to the variations of temperature and saturation.