Abstract

Thermal oil recovery methods have been widely used not only in heavy oil reservoirs, but also in light oil reservoir with Waterflooding to improve oil recovery. The Steamflooding could be considered as an effective way to enhance the oil displacement especially in heterogeneous reservoirs The field, of 58-years of production history, is located in South of Iraq. It has 40 producing wells. There was an infinite active aquifer located at the east and west flanks. The strength of this aquifer from the west flank is much larger than its in the east flank because the reservoir permeability at the eastern boundaries is lower than as at the western one for all the layers; therefore, Twenty injection wells were drilled at the east flank to maintain the aquifer water approaching to the reservoir. The average surface area for this reservoir is 142 km2 and average formation depth of 10350 ft subsea with a maximum vertical oil column of 350 ft. Average porosity is 21%. The oil is 34°API with an average initial bubble point pressure of 2660 psia. Current reservoir pressure is approximately 4200 psia and the reservoir temperature is 210°F. In this study, a thermodynamic reservoir simulation has been adopted to investigate the competence of Steamflooding to improve oil recovery.

The objective of this work was to examine the feasibility of steam-injection processes, so a thermodynamical reservoir model (CMG-STARS) has been applied to demonstrate the effect of using steam injection as a heating agent to increase the sweep efficiency in this heterogeneous formation. The twenty injection wells have been converted to steam injection for twelve future prediction years. The process has demonstrated a considerable increase of the cumulative oil production. This result has been compared with the base scenario of water injection at the same injection rates of 10,000 STB/DAY per well. The water injection scenario has been done by CMG-IMEX. This incremental has been proved over most of the production wells that have distributed among the reservoir by showing a significant difference between the two cases.

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