Method and system for determining fluid level change using pressure monitoring of annular gas

1. A method, comprising:

creating a chamber within an annulus between a wellbore casing and a drillpipe, wherein an upper boundary of the chamber comprises a seal and a lower boundary of the chamber comprises a liquid surface;

determining a volume of the chamber at a first time, wherein determining the volume of the chamber comprises:

measuring, using a pressure gauge, a first pressure within the chamber,

changing an amount of a gas in the chamber using a gas pump,

measuring, using the pressure gauge, a second pressure within the chamber,

determining a first volume of gas within the chamber based on the first and second pressure measurements and the change in the amount of gas, and

determining a first fluid level based on the first volume of the chamber.

2. The method of claim 1 , further comprising:

determining a second volume of the chamber at a second time;

determining a second fluid level based on the second volume of the chamber; and

determining a fluid loss by calculating a difference between the first fluid level and the second fluid level.

3. The method of claim 2 , further comprising:

creating a fluid loss control plan based on the fluid loss; and

executing the fluid loss control plan.

4. The method of claim 1 , wherein the seal comprises an inflatable packer disposed in the annulus.

5. The method of claim 1 , wherein the seal comprises a blowout preventer.

6. The method of claim 5 , wherein changing an amount of gas in the chamber comprises pumping gas through a manual kill valve on the blowout preventer.

7. The method of claim 1 , wherein changing an amount of gas in the chamber comprises:

installing a specialized drillpipe;

connecting a gas conduit to the specialized drillpipe; and

pumping gas through the gas conduit.

8. The method of claim 7 , wherein the gas conduit is a flexible gas hose.

9. The method of claim 7 , wherein the pressure gauge is disposed on the gas conduit.

10. The method of claim 1 , wherein the pressure gauge is disposed on the seal.

11. The method of claim 1 , wherein the volume of gas within the chamber is calculated with an ideal gas equation.

12. An apparatus, comprising:

a casing disposed within a wellbore;

a drillpipe disposed within the casing, wherein an annulus is created between the casing and the drillpipe;

a seal disposed in the annulus;

a chamber, wherein an upper boundary of the chamber comprises the seal and a lower boundary of the chamber comprises a surface of a liquid;

a pressure gauge connected to the chamber;

a specialized drillpipe section threadably connected to the drillpipe; and

a flexible gas hose fluidly connected to the annulus through the specialized drillpipe section.

13. The apparatus of claim 12 , wherein a fluid level comprises a distance between the seal and the surface of the fluid.

14. The apparatus of claim 12 , wherein the seal comprises an inflatable packer disposed in the annulus.

15. The apparatus of claim 12 , wherein the seal comprises a blowout preventer.

16. The apparatus of claim 15 , wherein the pressure gauge is installed on a choke line.

17. The apparatus of claim 15 , wherein the pressure gauge is a digital and high frequency sampling pressure gauge.

18. The apparatus of claim 15 , wherein a kill line is connected from a gas source to the blowout preventer.

19. The apparatus of claim 12 , wherein a hard conduit is connected to the drillpipe.