Plant and a method for increased oil recovery
AssigneeStatoil ASA
InventorsOla Olsvik, Erling Rytter, Jostein Sogge, Jan Age Stensen
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Abstract
A method for increasing oil recovery from an oil reservoir by injection of gas into the reservoir, is described. The method comprises separation of air into an oxygen-rich fraction and a nitrogen-rich fraction, reformation of natural gas together with oxygen to produce a synthesis gas for production of methanol or other oxygenated hydrocarbons or higher hydrocarbons. The raw synthesis products and a waste gas from the synthesis are separated, and the nitrogen-rich fraction and at least a part of the waste gas are injected into the oil reservoir to increase the oil recovery from the reservoir. A plant for performing the method is also described.
Claims11
A method for increasing oil recovery from an oil reservoir in which method gas is injected into the reservoir, comprising:
- separating air into an oxygen-rich fraction and a nitrogen-rich fraction;
- providing a natural gas stream and leading the natural gas stream and at least a part of the oxygen-rich fraction to a reformer for conversion to synthesis gas mainly comprising H2, CO, and CO2 in addition to lower amounts of non-converted methane, water vapor, and nitrogen;
- forming methanol or other oxygenated hydrocarbons or higher hydrocarbons from the synthesis gas in a synthesis unit;
- withdrawing a raw synthesis product and a waste gas from the synthesis unit;
- and
- injecting the nitrogen-rich fraction and at least a part of the waste gas into the oil reservoir to increase the oil recovery from the reservoir;
- and,
- wherein at least a portion of the waste gas from the synthesis unit is sent to a CO2 recovery unit, including a CO shift converter, wherein CO2 is removed and injected into the reservoir.
A plant for providing gas for down-hole injection for pressure support in an oil reservoir for recovery of hydrocarbons and production of oxygenated hydrocarbons or higher hydrocarbons from natural gas, comprising:
- an air separation unit for production of an oxygen-rich fraction for supply to processes that require oxygen, and a nitrogen-rich fraction for injection;
- a reformer for conversion of a mixture of natural gas, water, and oxygen or oxygen enriched air from the air separation unit into a synthesis gas comprising mainly H2, CO, CO2 and small amounts of methane in addition to any inert gas;
- a synthesis unit for conversion of the synthesis gas for synthesis of oxygenated hydrocarbons, or for synthesis of higher hydrocarbons;
- means for injecting gas into the reservoir;
- means for transferring nitrogen from the air separation unit to the means for injecting gas;
- and
- means for transferring at least a part of a waste gas from the synthesis unit to the means for injecting gas, and further comprising a tail gas treatment unit for removing CO by a shift reaction and separating hydrogen from a remaining tail gas.
A plant for providing gas for down-hole injection for pressure support in an oil reservoir for recovery of hydrocarbons and production of oxygenated hydrocarbons or higher hydrocarbons from natural gas, comprising:
- an air separation unit configured to produce an oxygen-rich fraction and a nitrogen-rich fraction for injection;
- a reformer configured to convert of a mixture of natural gas, water, and oxygen or oxygen enriched air from the air separation unit into a synthesis gas comprising mainly H2, CO, CO2 and small amounts of methane and inert gas;
- a synthesis unit configured to convert the synthesis gas for synthesis of oxygenated hydrocarbons, or for synthesis of higher hydrocarbons;
- an injection plant positioned to inject gas into the reservoir;
- a first line in communication with the air separation unit and configured to transfer nitrogen therefrom to the injection plant;
- and
- a second line in communication with the synthesis unit and configured to transfer at least a portion of a waste gas therefrom to the injection plant, and further comprising a tail gas treatment unit configured to remove CO by a shift reaction and separation of hydrogen from a remaining tail gas.
Dependencies are inferred from the claim text.