Methods for foam and gel injections into a well and enhanced foaming and gelations techniques

1. A method, comprising:

providing an injection well extending from a surface into a formation; and

alternatingly pumping a foam injectant and a gel injectant into the injection well;

wherein the foam injectant comprises:

a liquid phase comprising a surfactant and water; and

a gas phase comprising a gas;

wherein the gel injectant comprises a water-soluble polymer and a crosslinker; and

wherein the foam injectant and the gel injectant are injected at separate times and sequentially; and

using the injected gel injectant and the injected foam injectant to drive a reservoir fluid in the formation to a production well a distance from the injection well.

2. The method of claim 1 , wherein the gel injectant is gelled in-situ in the formation, wherein injecting the gel injectant comprises:

injecting components of the gel injectant sequentially into the formation through the injection well; and

waiting a gelation time for crosslinking between the water-soluble polymer.

3. The method of claim 1 , wherein the gel injectant is gelled ex-situ at the surface, wherein injecting the gel injectant comprises:

mixing the water-soluble polymer and the crosslinker with water at the surface;

waiting a gelation time for crosslinking between the water-soluble polymer to form a gel; and

injecting the gel into the formation.

4. The method of claim 1 , wherein the foam injectant is foamed in-situ in the formation, wherein injecting the foam injectant comprises:

injecting the surfactant, the water, and the gas as separate components into the injection well at an injection pressure;

wherein the components mix into a foam as the components are injected.

5. The method of claim 1 , wherein the foam injectant is foamed ex-situ at the surface, wherein injecting the foam injectant comprises:

mixing the surfactant, the water, and the gas in a foam generator to create a foam; and

pumping the foam down the injection well at an injection pressure.

6. The method of claim 1 , wherein the foam injectant is formed in-situ, and the gel injectant is formed at the surface.

7. The method of claim 1 , further comprising:

extending an injection string into the injection well, wherein the injection string comprises a downhole sound wave tool connected to a string of pipe,

wherein the downhole sound wave tool is selected from a group consisting of an ultrasonic device, an infrasonic device, and an acoustic device; and

wherein the downhole sound wave tool comprises a body that is a sub threadably connected at an end of the string of pipe; and

sending sound waves from the downhole sound wave tool into the formation to enhance foaming or gelling.

8. The method of claim 1 , further comprising monitoring injection of the gel injectant and the foam injectant using at least one downhole sensor in the injection well and at least one surface sensor at the surface.

9. The method of claim 1 , further comprising injecting water into the formation prior to injecting the gel injectant and the foam injectant.

10. A method, comprising:

providing an injection well extending from a surface into a formation; and

pumping a gel injectant and a foam injectant simultaneously through the injection well and into the formation;

wherein the foam injectant comprises:

a liquid phase comprising a surfactant and water; and

a gas phase comprising a gas; and

wherein the gel injectant comprises a water-soluble polymer and a crosslinker; and

using the injected gel injectant and the injected foam injectant to drive a reservoir fluid in the formation to a production well a distance from the injection well.

11. The method of claim 10 , wherein the gel injectant is gelled in-situ in the formation, and the foam injectant is foamed ex-situ at surface.

12. The method of claim 10 , wherein the gel injectant is gelled ex-situ at the surface, and the foam injectant are foamed ex-situ at the surface.

13. The method of claim 10 , wherein gel injectant is gelled in-situ in the formation, and foam injectant is foamed in-situ in the formation.

14. The method of claim 13 , further comprising injecting a triggering fluid down the injection well to simultaneously gel the gel injectant and foam the foam injectant in-situ by the triggering fluid.

15. The method of claim 10 , further comprising:

threadedly connecting a downhole sound wave tool to an end of a string of pipe, wherein the downhole sound wave tool comprises a body that is a sub with a threaded connection; and

emitting sound waves from the downhole sound wave tool into the formation after injecting the gel injectant and the foam injectant into the formation.

16. A system, comprising:

an injection well extending from a surface into an underground formation, wherein the injection well comprises:

an injection wellhead positioned at an opening to the injection well at the surface; and

injection tubing extending from the injection wellhead a depth into the injection well;

a production well extending from the surface and in fluid communication with the underground formation;

a foam feed fluidly connected to the injection well via a foam feed line, wherein the foam feed comprises a surfactant and water;

a gel feed fluidly connected to the injection well via a gel feed line; and

a foam line valve positioned along the foam feed line and a gel line valve positioned along the gel feed line to selectively open and close the foam feed line and the gel feed line, respectively.

17. The system of claim 16 , further comprising an injection string extending from the surface into the injection well, wherein the injection string comprises a downhole sound wave tool connected to a string of pipe, wherein the downhole sound wave tool comprises a body that is a sub threadably connected at an end of the string of pipe, and wherein the downhole sound wave tool is selected from a group consisting of an ultrasonic device, an infrasonic device, and an acoustic device.

18. The system of claim 16 , further comprising at least one sensor positioned in the injection well or at the surface.

19. The system of claim 16 , wherein the foam feed further comprises a gas selected from a group consisting of nitrogen gas and carbon dioxide gas.

20. The system of claim 16 , wherein the gel feed comprises sulfonated polyacrylamide and a Cr(III) crosslinker.