Addition of monovalent salts for improved viscosity of polymer solutions used in oil recovery applications
AssigneeSaudi Arabian Oil Company
InventorsSaleh F. Hassan, Abdulkareem M. AlSofi
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Abstract
An oil recovery composition having a brine, a hydrolyzable polymer, and a monovalent cations to divalent cations ration in the range of about 2.5:1 to 3:1 is provided. An oil recovery composition may be formed from a brine recovered from production water and a polymer. A monovalent salt may be added to the brine recovered from production water to form a modified brine and achieve a modified monovalent cations to divalent cations ratio in the range of about 2.5:1 to 3:1. Processes for forming the oil recovery composition and enhanced oil recovery using the oil recovery composition are provided.
Claims11
A method of forming a composition having a target viscosity for enhancing oil recovery in a hydrocarbon reservoir formation:
- determining a mass ratio of monovalent cations to divalent cations of a brine;
- adding a monovalent salt to the brine to modify the mass ratio of monovalent cations to divalent cations of the brine to a range of 2.5:1 to 3:1, the modified brine having a Na+ concentration in the range of 22,166 milligrams/liter (mg/L) to 30,624 mg/L;
- and
- adding a hydrolyzable polymer to the brine to form the composition having the target viscosity, wherein the hydrolyzable polymer has a concentration of 0.05 weight (wt) % to 0.5 wt %.
Dependencies are inferred from the claim text.