SYSTEMS AND METHODS FOR GENERATING IN-SITU CARBON DIOXIDE DRIVER GAS FOR USE IN ENHANCED OIL RECOVERY

• US 20100314136A1
• Filed: 08/25/2010
• Published: 12/16/2010
• Est. Priority Date: 05/20/2007
• Status: Active Grant

• Current Assignee: Pioneer Energy, Inc.
• Original Assignee: Pioneer Energy, Inc.
• Inventors: Zubrin, Robert M., Berggren, Mark H.
• Granted Patent: US 8,616,294 B2
• Time in Patent Office: Days
• US Class Current: 166/402
• CPC Class Codes: E21B 43/164 Injecting CO2 or carbonated water in combination with organic material C09K8/594
• CPC Class Codes: E21B 43/168 Injecting a gaseous medium
• CPC Class Codes: Y02C 20/40 of CO2
• CPC Class Codes: Y02P 90/70 Combining sequestration of CO2 and exploitation of hydrocarbons by injecting CO2 or carbonated water in oil wells

Abstract

The present invention is an in-situ apparatus for generating carbon dioxide gas at an oil site for use in enhanced oil recovery (EOR). The apparatus includes a steam generator adapted to boil and superheat water to generate a source of superheated steam, as well as a source of essentially pure oxygen. The apparatus also includes a steam reformer adapted to react a carbonaceous material with the superheated steam and the pure oxygen, in an absence of air, to generate a driver gas comprising primarily carbon dioxide gas and hydrogen gas. A separator is adapted to separate at least a portion of the carbon dioxide gas from the rest of the driver gas to generate a carbon dioxide-rich driver gas and a hydrogen-rich fuel gas. A compressor is used for compressing the carbon dioxide-rich driver gas for use in enhanced oil recovery, and the compressed carbon dioxide-rich driver gas, with substantially no oxygen, is injected to a predetermined depth in order to enhance oil recovery at the oil site. Unlike traditional CO₂-EOR, which requires large power plants stationed near metropolitan areas and expensive pipeline networks, the in-situ apparatus can be placed or constructed at the site of the oil field, while a portion of the carbonaceous material may be obtained from a site outside the oil field.

Claims

1. An in-situ apparatus for generating carbon dioxide gas near an oil site for use in enhanced oil recovery, comprising:

a steam generator adapted to boil and superheat water to generate a source of superheated steam;

a source of essentially pure oxygen;

a steam reformer, located adjacent to the oil site, adapted to react a carbonaceous material with the superheated steam and the pure oxygen, in an absence of air, to generate a driver gas comprising primarily carbon dioxide gas and hydrogen gas, wherein at least a portion of the carbonaceous material is obtained from a location outside the oil site;

a separator adapted to separate at least a portion of the carbon dioxide gas from the driver gas to generate a carbon dioxide-rich driver gas and a hydrogen-rich fuel gas; and

a compressor for compressing the carbon dioxide-rich driver gas for use in enhanced oil recovery, wherein the compressed carbon dioxide-rich driver gas, with substantially no oxygen, is injected to a predetermined depth in order to enhance oil recovery at the oil site.

2. The apparatus of claim 1, wherein the carbonaceous material is selected from the group consisting of coal, biomass, natural gas, crude petroleum, ethanol, methanol, and trash.

3. The apparatus of claim 1, wherein heat from the hot driver gas exiting the steam reformer is used to boil and superheat water to generate a portion of the required superheated steam.

4. The apparatus of claim 1, further comprising a gas turbine adapted to utilize a portion of the hydrogen-rich fuel gas to generate electricity, wherein waste heat from the gas turbine is used to provide heat needed to boil the water.

5. The apparatus of claim 4, wherein the electricity generated has substantially less associated carbon dioxide emissions than electricity generated from combustion of the carbonaceous material.

6. The apparatus of claim 1, wherein the driver gas further comprises residual carbon monoxide, and wherein the apparatus further comprises:

a water gas-shift reactor disposed downstream of the steam reformer for converting the residual carbon monoxide into additional carbon dioxide gas and additional hydrogen gas.

7. The apparatus of claim 1, wherein the driver gas further comprises residual carbon monoxide, and wherein the apparatus further comprises:

a methanation reactor disposed downstream of the steam reformer for converting the residual carbon monoxide into methane.

8. The apparatus of claim 1, further comprising:

a furnace adapted to utilize a portion of the hydrogen-rich fuel gas to generate heat necessary to drive the steam reformer.

9. The apparatus of claim 1, further comprising:

a heat exchanger disposed between the steam generator and the steam reformer adapted to exchange heat between the hot driver gas exiting the steam reformer and the steam entering the steam reformer.

10. The apparatus of claim 9, further comprising:

a condenser disposed after the heat exchanger adapted to condense and cool the driver gas before entering the separator.

11. The apparatus of claim 1, further comprising:

a furnace adapted to utilize a portion of the hydrogen-rich fuel gas to generate a portion of the heat necessary to drive the steam reformer.

12. The apparatus of claim 1, wherein the steam reformer operates at a temperature of approximately 600°

C. to 1000°

C.

13. The apparatus of claim 1, wherein the steam reformer operates at a pressure of approximately 5 bar to 100 bar.

14. The apparatus of claim 1, wherein the separator is a methanol-based separator operating in a temperature-swing cycle between approximately −

60°

C. and +40°

C., and a pressure-swing cycle between approximately 1 bar and 100 bar.

15. The apparatus of claim 1, further comprising:

a control system adapted to control an operation of the apparatus based on a temperature, a pressure, and a gas composition of the driver gas in real-time by controlling an input oxygen-to-steam ratio.

16. The apparatus of claim 1, wherein the steam reformer is selected from the group consisting of a fixed bed reformer, a fluidized bed reformer, and an entrained-flow reformer.

17. A method for generating carbon dioxide gas near an oil site for use in enhanced oil recovery, comprising:

providing a source of superheated steam;

providing a source of essentially pure oxygen;

steam reforming a carbonaceous material with the superheated steam and the pure oxygen to generate a driver gas comprising primarily carbon dioxide gas and hydrogen gas, wherein the steam reforming reaction is performed adjacent to the oil site and in an absence of air;

separating at least a portion of the carbon dioxide gas from the driver gas to generate a carbon dioxide-rich driver gas and a hydrogen-rich fuel gas;

compressing the carbon dioxide-rich driver gas for use in enhanced oil recovery; and

injecting the compressed portion of the carbon dioxide-rich driver gas, with substantially no oxygen, to a predetermined depth in order to enhance oil recovery at the oil site.

18. The method of claim 17, wherein the carbonaceous material is selected from the group consisting of coal, biomass, natural gas, crude petroleum, ethanol, methanol, and trash.

19. The method of claim 17, further comprising:

generating electricity using a portion of the hydrogen-rich fuel gas.

20. The method of claim 17, further comprising:

utilizing a water gas-shift reaction downstream of the steam reforming reaction to convert residual carbon monoxide in the driver gas into additional carbon dioxide gas and additional hydrogen gas.