Surfactant formulations for foam flooding
View Patent ↗A foam generating surfactant formulation includes a betaine, an alpha-olefin sulfonate and a nanofluid. The betaine is preferably a cocamidopropyl betaine or laurel betaine. The alpha-olefin sulfonate is preferably an anionic surfactant having between 8 and 18 carbon atoms per molecule. The nanofluid is preferably an oil-in-water nanofluid that includes an emulsifying surfactant, a solvent, a co-solvent and water. The addition of the nanofluid increases the thermal stability and salt resistance of the foam generating surfactant.
1. A method of producing a treatment foam in a well, the method comprising the steps of:
mixing together a betaine, an alpha-olefin sulfonate and a microemulsion to form a foam generating surfactant formulation;
pumping the foam generating surfactant formulation into the well; and
forcing gas into the well to contact the foam generating surfactant formulation to produce the treatment foam.
2. The method of claim 1 , wherein the step of pumping the foam generating surfactant formulation further comprises adding the foam generating surfactant formulation to a carrier fluid that is pumped into the well.
3. The method of claim 2 , wherein the foam generating surfactant formulation is added to the carrier fluid in a ratio of between about 2 and 5 gallons per thousand gallons of carrier fluid.
4. The method of claim 1 , wherein the step of forcing gas into the well further comprises forcing into the well a gas selected from the group consisting of nitrogen, hydrocarbon gases, hydrocarbon/solvent gas mixtures, hydrogen sulfide and flue gases or combinations thereof.
5. The method of claim 1 , wherein the betaine is selected from the group consisting of cocamidopropyl betaine and laurel betaine.
6. The method of claim 1 , wherein the alpha-olefin sulfonate is an anionic surfactant having between 8 and 18 carbon atoms per molecule.
7. The method of claim 6 , wherein the alpha-olefin sulfonate has between 8 and 12 carbon atoms.
8. The method of claim 1 , wherein the formulation includes about 1 part betaine to between about 2 and 5 parts alpha-olefin sulfonate.
9. The method of claim 8 , wherein the formulation includes about 1 part betaine to about 3.4 parts alpha-olefin sulfonate.
10. The method of claim 1 , wherein the microemulsion comprises an oil-in-water microemulsion.
11. The method of claim 1 , wherein the microemulsion comprises:
an emulsifying surfactant;
a solvent,
a co-solvent; and
water.
12. The method of claim 11 , wherein the solvent is a citrus terpenes.
13. The method of claim 12 , wherein the solvent is d-limonene.
14. The method of claim 11 , wherein the emulsifying surfactant comprises a mixture of ethoxylated castor oils and ethoxylated alcohols.
15. The method of claim 11 , wherein the emulsifying surfactant has a hydrophile-lipophile balance value of between 8 and 18.
16. The method of claim 11 , wherein the emulsifying surfactant is selected from the group consisting of ethoxylated alcohol and ethoxylated vegetable oil.
17. The method of claim 1 , wherein the foam generating surfactant formulation comprises:
between about 5 and about 70 percent by weight alpha-olefin sulfonate;
between about 10 and about 20 percent by weight betaine;
between about 5 and about 15 percent by weight emulsifying surfactant;
between about 3 and about 10 percent by weight solvent,
between about 3 and about 15 percent by weight co-solvent; and
greater than about 0 to about 10 percent by weight water.