Borehole fluid gel strength measurement

1. A method of performing a borehole operation with a borehole fluid comprising:

applying an amplitude oscillation deformation force to a sample of the borehole fluid over a period of time;

measuring the deformation force from the sample;

determining a storage modulus of the borehole fluid over the period of time based on the measured deformation force;

determining a gel strength of the borehole fluid by correlation with the storage modulus;

comparing the gel strength with a selected gel strength for performing the borehole operation and if the gel strength is outside of a range with respect to the selected gel strength for performing the borehole operation, adjusting a drilling parameter, a composition of the borehole fluid, or a combination thereof; and

using the borehole fluid in the borehole operation.

2. The method of claim 1 , further comprising applying the amplitude oscillation deformation force to the borehole fluid continuously over the period of time.

3. The method of claim 1 , where the period of time comprises a gelation period for the borehole fluid.

4. The method of claim 1 , where applying an amplitude oscillation deformation force to the borehole fluid comprises imparting a force using a piezoelectric device.

5. The method of claim 1 , where applying an amplitude oscillation deformation force to the borehole fluid comprises maintaining a frequency and amplitude of the oscillation deformation force over the period of time.

6. The method of claim 1 , where applying an amplitude oscillation deformation force to the borehole fluid further comprises adjusting an amplitude while maintaining a frequency and determining a dynamic yield stress of the borehole fluid based on when the borehole fluid sample transitions from linear viscoelastic deformation to dynamic yield stress.

7. The method of claim 1 , where the borehole fluid comprises drilling fluid and the borehole operation comprises drilling a borehole.

8. An apparatus for evaluating the gel strength of a borehole fluid for use in a borehole operation, comprising:

a piezoelectric device operable to apply an amplitude oscillation deformation force to a sample of the borehole fluid over a period of time;

a sensor operable to measure the deformation force from the sample of the borehole fluid; and

a processor operable to:

determine a storage modulus of the borehole fluid over time based on the measured deformation force;

determine a gel strength of the borehole fluid by correlation with the storage modulus; and

compare the gel strength with a selected gel strength for performing the borehole operation to determine if the gel strength is within a range with respect to the selected gel strength for performing the borehole operation.

9. The apparatus of claim 8 , where the piezoelectric device is operable to apply the amplitude oscillation deformation force to the borehole fluid continuously over the period of time.

10. The apparatus of claim 8 , where the period of time comprises a gelation period for the borehole fluid.

11. The apparatus of claim 8 , where the piezoelectric device is operable to apply the amplitude oscillation deformation force by imparting force to a spring and the sensor comprises a piezoelectric sensor.

12. The apparatus of claim 8 , where the piezoelectric device is operable to apply the amplitude oscillation deformation force to the sample of the borehole fluid by maintaining a frequency and amplitude of the oscillation deformation force over the period of time.

13. The apparatus of claim 8 , where the piezoelectric device is operable to apply the amplitude oscillation deformation force to the borehole fluid sample by adjusting an amplitude of the deformation force while maintaining a frequency until the sample transitions from linear viscoelastic deformation to dynamic yield stress and where the processor is operable to determine the dynamic yield stress of the borehole fluid sample based on the transition.

14. The apparatus of claim 8 , where the sample of the borehole fluid comprises drilling fluid and the borehole operation comprises drilling a borehole.

15. A method of determining the gel strength of a fluid comprising:

applying a linear amplitude oscillation deformation force to the fluid in a normal direction relative to the fluid over a period of time;

measuring the deformation force from the fluid continuously over the period of time using a dynamic pressure sensor on the opposite side of the fluid from the force being applied;

determining a storage modulus of the fluid continuously over the period of time based on the measured deformation force to produce a storage modulus profile; and

determining a gel strength of the fluid by correlation with the storage modulus profile based on a ratio of a dynamic viscosity of the fluid to a shear viscosity of the fluid.

16. The method of claim 15 , further comprising applying the linear amplitude oscillation deformation force to the fluid continuously over the period of time.

17. The method of claim 15 , where the period of time comprises a gelation period for the fluid.

18. The method of claim 15 , where applying the linear amplitude oscillation deformation force to the fluid comprises imparting a force using a piezoelectric device.

19. The method of claim 15 , where applying the linear amplitude oscillation deformation force to the fluid comprises maintaining a frequency and amplitude of the oscillation deformation force over the period of time.

20. The method of claim 15 , where applying the linear amplitude oscillation deformation force to the fluid further comprises adjusting an amplitude while maintaining a frequency and determining a dynamic yield stress of the fluid based on when the fluid sample transitions from linear viscoelastic deformation to dynamic yield stress.