Zero emission steam generation process

Abstract

This invention provides a new process to generate steam directly from untreated water produced simultaneously with thermally recovered crude oil, and to inject the steam and combustion products into a hydrocarbon reservoir to recover hydrocarbons and to sequester a portion of the carbon dioxide produced during the creation of steam. The invention removes the ongoing additional water requirements for thermal oil recovery and the need for surface treating of produced water for re-use, yielding improved process efficiencies, reduced environmental impact, and improved economic value.

Description

FIELD OF THE INVENTION[0001]The current invention pertains to an area of generating of steam for the thermal recovery of oil and bitumen from subsurface hydrocarbon reservoirs. Specifically, to the area of using an oxygen fuel combustor as a steam generator.BACKGROUND OF THE INVENTION[0002]Thermal oil recovery projects, including but not limited to Steam Assisted Gravity Drainage (SAGD), Cyclic Steam Stimulation (CSS), or Steam Flooding, or recovery processes that potentially start with steam injection (e.g. in situ combustion) utilize large amounts of water in the form of steam, to carry heat energy underground to mobilize the oil, heavy oil, or bitumen. This water, typically in a ratio of three or higher parts water to one part oil, is transported back to the surface with the oil. Previous processes have required extensive water treatment and handling to clean the water prior to it being re-used as boiler feed water. For example, water treatment can involve one or more of gravity ...

AI Technical Summary

Benefits of technology

[0016]Specifically, the process uses the apparatus, designed as a gas generator, as a new concept of the process vessel to use subterranean waters, which are co-produced with oil, directly for steam without softening or treating prior to boiling. Thermal recovery includes, but not limited to, Steam Assisted Gravity Drainage (SAGD), Cyclic Steam Stimulation (CSS), Steam Flooding, or combined steam-additive processes where the additive can be one or more of non-condensable gas, solvent, or surfactant. In addition the process captures all combustion gases produced and injects steam and combustion gasses underground simultaneously, removing the ongoing requirement for make up water in thermal oil recovery.

[0038]According to a preferred embodiment, the feed water includes untreated subterranean water, which is co-produced with oil production. The ability to use this untreated produced water will result in following advantages:

[0039]It will remove the ongoing requirement for additional water into a thermal oil recovery process such as, but not limited to, Steam Assisted Gravity Drainage (SAGD), Cyclic Steam Stimulation (CSS), or Steam Flooding, or other recovery processes that start with steam injection e.g. in situ combustion. By capturing the water of combustion, once the production process is stable, no further water will be required.

[0040]It will increase the thermal efficiency of the process. By capturing heat lost to stack emissions and further piping losses, thermal efficiencies can increase by more than 10%.

[0041]It will reduce thermal oil recovery process capital and operating costs by up to 50%, through the complete removal of water treatment equipment.

Problems solved by technology

Dealing with the impurities result in increased capital, maintenance, operating cost, and environmental impact.

Usually in a traditional thermal oil recovery system the water treatment process, accounts for up to 50% of the operating costs.

Moreover, all thermal recovery projects have ongoing water requirements to make up water losses and water treating blow down.

Traditionally heating / cooling processes take place in heat exchanger vessels and devices, which have one common deficiency: all those vessels and devices used in all industries maintain a separation between reactive substances and the targets of heating or cooling.

This separation reduces the efficiency of the heaters and coolers substantially.

In all those cases the methods of capturing carbon dioxide for use in enhanced hydrocarbon recovery are complicated and capital intensive.

In thermal recovery however, free gas in a reservoir may lower the in-situ reservoir temperature, which in turn will reduce oil recovery.

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