Devices and related methods for estimating accumulated thermal damage of downhole components

1. A thermal aging estimator for use in a borehole having an ambient temperature of at least 200° F., comprising:

a heat-sensitive component;

a thermal aging element positioned adjacent to the heat-sensitive component while in the ambient temperature of at least 200° F., the thermal aging element being configured to have permanent change in an electrical property in response to a thermal exposure, the permanent change correlating to cumulative thermal damage from the thermal exposure, wherein the thermal aging element is a thin-film resistor; and

a change estimating circuit connected to the thermal aging element and configured to apply an electrical signal to the thermal aging element.

2. The thermal aging estimator of claim 1 , wherein the thermal exposure is comprised of a plurality of sub-exposures, wherein each sub-exposure is defined by a time duration and a temperature magnitude, and wherein the permanent change correlates to an accumulation of thermal damage from all of the sub-exposures.

3. The thermal aging estimator of claim 1 , wherein the heat-sensitive component is an electrically energized component.

4. The thermal aging estimator of claim 1 , wherein the change estimating circuit is formed of members that do not have a permanent change in resistance in response to the thermal exposure.

5. The thermal aging estimator of claim 1 , wherein the correlation is defined by the Arrhenius equation.

6. The thermal aging estimator of claim 1 , wherein the change estimating circuit is further configured to estimate the permanent change in the electrical property.

7. The thermal aging estimator of claim 1 , wherein the thermal aging element is at least partially formed of a material that degrades in response to the thermal exposure.

8. The thermal aging estimator of claim 1 , wherein the change estimating circuit is a Wheatstone bridge.

9. The thermal aging estimator of claim 1 , wherein the heat-sensitive component, the thermal aging element, and the change estimating circuit are positioned on a common platform.

10. A method of operating a heat-sensitive component, comprising:

positioning a thermal aging element adjacent to the heat-sensitive component;

conveying the thermal aging element and the heat-sensitive component into a borehole having an ambient temperature of at least 200° F.;

energizing the operating downhole tool to perform a predetermined function; and

estimating the thermal aging of the heat-sensitive component by estimating a permanent change of an electrical property of the thermal aging element due to a thermal exposure, wherein the permanent change correlates to cumulative thermal damage from the thermal exposure, and wherein the thermal aging element is a thin-film resistor.

11. The method of claim 10 , wherein the thermal exposure is comprised of a plurality of sub-exposures, wherein each sub-exposure is defined by a time duration and a temperature magnitude, and wherein the permanent change correlates to an accumulation of thermal damage from all of the sub-exposures.

12. The method of claim 10 , wherein the circuit is formed of members that do not have a permanent change in resistance in response to the thermal exposure.

13. The method of claim 10 , wherein the correlation is defined by the Arrhenius equation.

14. The method of claim 10 , wherein the thermal aging of the heat-sensitive component is estimated while the thermal aging element is still in the borehole.

15. The method of claim 10 , further comprising estimating the thermal aging of the heat-sensitive component after retrieving the thermal aging element and the heat-sensitive component from the borehole.

16. The method of claim 15 , further comprising deploying the downhole tool again if the determined estimated change is below a predetermined value.

17. A method for estimating a thermal aging of a heat-sensitive component, comprising:

positioning a thermal aging element adjacent to the heat-sensitive component;

conveying the thermal aging element and the heat-sensitive component into a borehole having an ambient temperature of at least 200° F.; and

estimating the thermal aging of the heat-sensitive component by estimating a permanent change of an electrical property of the thermal aging element, wherein the permanent change correlates to cumulative thermal damage from the thermal exposure and wherein the thermal aging element is a thin-film resistor.