Chemically enhanced thermal recovery of heavy oil

Abstract

Described herein are methods for removing heavy oils from underground reservoirs. The methods involve the use of chemical compositions in combination with steam techniques for the efficient removal of heavy oils.

Description

BACKGROUND OF THE INVENTION[0001]Heavy oil sand, such as tar sand, is a major source of petroleum. Heavy oil-containing reservoirs, however, contain crude petroleum or bitumen of such high viscosity that it cannot be recovered by conventional petroleum recovery techniques. However, once the crude petroleum or bitumen is recovered, surface-milling processes can separate the bitumen from sand. The separated bitumen may be converted to light hydrocarbons using conventional refinery methods.[0002]Steam has long been used in the recovery of oil from these heavy oil-containing reservoirs. For example, thermal recovery techniques such as cyclic steam simulation (CSS), Huff and Puff, and Steam Assisted Gravity Drainage (SAGD) have been used. Although these techniques have high recovery yields, their energy efficiency is poor.[0003]Another approach involves enhanced oil recovery (EOR) techniques. These processes involve the use of surfactants in the presence of alkali solutions and salts to ...

AI Technical Summary

Benefits of technology

The patent describes methods for removing heavy oils from underground reservoirs using chemicals and steam techniques. The advantages of this approach include efficient removal of heavy oils and improved recovery of oil reserves. The technical effects of this patent include improved oil recovery and more efficient well cleaning.

Problems solved by technology

Heavy oil-containing reservoirs, however, contain crude petroleum or bitumen of such high viscosity that it cannot be recovered by conventional petroleum recovery techniques.

Although these techniques have high recovery yields, their energy efficiency is poor.

In these processes, the temperature is usually below 80° C., which can limit the recovery of the heavy oils due to their high viscosity.

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