Sagd Process In Fractured Heavy Oil Reservoirs

SAGD process can be an attractive recovery process for many fractured heavy oil reservoirs. Surfactant injection for improving conformance and increasing oil recovery has been successfully employed in a number of steam injection operations. Successful application of foaming surfactants to control injection profiles in steam processes has been reported and their use to limit steam flow through depleted zones of the reservoir during steam process has been proposed. This study was carried out to develop a methodology for SAGD studies and provide some understanding of the performance of foam forming surfactants in the SAGD process applied to fractured heavy oil reservoirs. This study presents an experimental investigation of the effect of horizontal and vertical fractures, well configurations and surfactant injection with steam on SAGD process in a 3-D model using two different heavy oils. A total 10 runs were conducted using a 30 cm × 30 cm × 10 cm rectangular-shaped box model. Temperature distributions, the rise and growth of the initial steam chamber were observed 25 thermocouples. A horizontal injection and production well pair were investigated with and without fractures. The effect of fracture orientation (vertical or horizontal) and surfactant concentration on steam-oil ratio (SOR) and oil recovery was studied using horizontal well pair scheme. The experimental results indicated that vertical fractures improved SAGD. Maximum oil recovery was observed during the horizontal injection-horizontal production well scheme with a fractured model, because of the favourable steam-chamber geometry. Runs showed that the location of the fractures affects the performance of the process. During the early stages of the runs, the fractured model gave significant higher SORs than those observed in the uniform permeability reservoir. The fractures were successful in shortening the time to generate near breakthrough condition between the two wells. In Surfactant-SAGD runs, maximum oil recovery observed using horizontal injection-horizontal production well scheme with fractures. The injection of surfactant from injector was attractive for mobile heavy oil by strong foaming and flooding functions at the initial stage when pre-heating effects were not enough. Surfactant-SAGD process was shortened the lead time and enhanced oil production rate after steam breakthrough