Alternating sagd injections

Abstract

Methods produce heavy oil with steam assisted gravity drainage. Such methods alternate a traditional steam injection with an injection of a steam-plus-non-condensable gas (such as CO2 or CO2-plus-diluent) mixture. The CO2 / diluent mixture is soluble in bitumen, leading to a reduction in viscosity of the heavy oil. Additionally, the steam-only injection reduces the accumulation of vapor NCG along the edge of the steam chamber, leading to improved thermal efficiency.

Description

PRIOR RELATED APPLICATIONS

[0001] This application is a non-provisional application which claims benefit under 35 USC §119(e) to U.S. Provisional Application Ser. No. 61 / 897,555 filed Oct. 30, 2013, entitled “ALTERNATING SAGD INJECTIONS,” which is incorporated herein in its entirety.FEDERALLY SPONSORED RESEARCH STATEMENT

[0002] Not applicable.FIELD OF THE DISCLOSURE

[0003] The disclosure generally relates to methods for improving hydrocarbon recovery utilizing alternating steam and steam-plus-additive injections.BACKGROUND OF THE DISCLOSURE

[0004] Canada and Venezuela have some of the largest deposits of a thick, heavy oil called “bitumen.” Bitumen is especially difficult to recover because it is wrapped around sand and clay, forming what is call “oil sands.” Furthermore, the viscosity of bitumen in a native reservoir is high—often in excess of 1,000,000 cP. It will not flow without being stimulated by methods such as the addition of solvent and / or heat.

[0005] Many approaches to recovering h...

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