Patent ID: 7481275

Claim:
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 H 2 , CO, and CO 2 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 CO 2 recovery unit, including a CO shift converter, wherein CO 2 is removed and injected into the reservoir.