Quantum dots based nanofluid for enhanced oil recovery in tight oil reservoir
A compound for use in oil recovery includes a quantum dot and a zwitterionic surfactant. The quantum dot has a diameter no greater than 25 nm and the quantum dot is bonded to the zwitterionic surfactant. A nanofluid for use in oil recovery includes the compound described above and a fluid carrier. A method for recovering oil from a formation includes flooding the formation with a nanofluid. The nanofluid has a quantum dot diameter no greater than 25 nm bonded to a zwitterionic surfactant and a fluid carrier.
1. A compound for use in oil recovery, the compound comprising:
a quantum dot having a diameter no greater than 25 nm;
a zwitterionic surfactant; and
a functional linkage on the quantum dot, the functional linkage comprising one of:
an amine or an ion thereof; and
carboxylic acid or an ion thereof;
wherein the zwitterionic surfactant is bonded to the quantum dot via the functional linkage.
2. The compound of claim 1 wherein the quantum dot is a polymer quantum dot.
3. The compound of claim 2 wherein the polymer quantum dot comprises poly(fluorene-alt-benzothiadiazole) and poly(styrene-co-maleic anhydride).
4. The compound of claim 1 wherein the quantum dot is a silicon quantum dot.
5. The compound of claim 1 wherein the compound does not aggregate below 90° C. for at least 30 days.
6. The compound of claim 1 wherein the compound does not aggregate in a saline solution of no greater than 15 wt % brine.
7. The compound of claim 1 wherein the zwitterionic surfactant is bonded to the quantum dot through a covalent bond.
8. The compound of claim 1 wherein the zwitterionic surfactant comprises a betaine zwitterionic surfactant.
9. A nanofluid for use in oil recovery, the nanofluid comprising:
the compound of claim 1 ; and
a fluid carrier.
10. The nanofluid of claim 9 wherein the fluid carrier comprises water.
11. The nanofluid of claim 9 wherein the fluid carrier comprises a brine.
12. The nanofluid of claim 9 wherein the compound of claim 1 has a concentration in the fluid carrier between 0.01 wt % and 0.10 wt %.
13. A method for recovering oil from a formation, the method comprising:
flooding the formation with a nanofluid, the nanofluid comprising a quantum dot having a diameter no greater than 25 nm bonded via a functional linkage on the quantum dot to a zwitterionic surfactant and a fluid carrier to form a chemically flooded formation;
wherein the functional linkage comprises one of:
an amine or an ion thereof; and
carboxylic acid or an ion thereof.
14. The method of claim 13 , further comprising flooding the chemically flooded formation with a brine.
15. The method of claim 13 , further comprising flooding the formation with a brine prior to flooding the formation with the nanofluid.