METHODS AND APPARATUS FOR EVALUATING DOWNHOLE CONDITIONS WITH RFID MEMS SENSORS

• US 20140111349A1
• Filed: 12/31/2013
• Published: 04/24/2014
• Est. Priority Date: 04/02/2007
• Status: Active Grant

• Current Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Original Assignee: Halliburton Energy Services Incorporated (Halliburton Company)
• Inventors: Roddy, Craig W., Ravi, Krishna M., Roberson, Mark W., Bartee, Charles, McGuire, Kristopher, Rothrock, Ginger, Goodwin, Scott
• Granted Patent: US 9,494,032 B2
• Time in Patent Office: Days
• US Class Current: 340/854.8
• CPC Class Codes: E21B 33/13 Methods or devices for cementing, for plugging holes, crevices or the like
• CPC Class Codes: E21B 43/25 Methods for stimulating production by vibrating earth formations E21B43/003
• CPC Class Codes: E21B 47/005 Monitoring or checking of cementation quality or level
• CPC Class Codes: E21B 47/01 Devices for supporting measuring instruments on drill bits, pipes, rods or wirelines; Protecting measuring instruments in boreholes against heat, shock, pressure or the like
• CPC Class Codes: E21B 47/13 by electromagnetic energy, e.g. radio frequency
• CPC Class Codes: G06K 19/07749 the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card

Abstract

A radio frequency identification (RFID) tag can include a die attached to an inductive-capacitive (LC) circuit including a capacitive element coupled to an inductive element. The LC circuit can have a resonant frequency that varies according to properties of fluid proximate the RFID tag. The RFID tag can further include a coating material disposed around the die to form an outer surface of the RFID tag. The coating material may have a thickness over a portion of the LC circuit, to permit a conductivity property of a fluid proximate the outer surface to affect the resonant frequency of the LC circuit such that the resonant frequency shifts to a second resonant frequency. Additional apparatus, systems, and methods are disclosed.

Claims

1. A radio frequency identification (RFID) tag, comprising:

a first die attached to a first inductive-capacitive (LC) circuit including a first capacitive element coupled to a first inductive element, the first LC circuit having a first resonant frequency; and

a first coating material disposed around the first die to form a first outer surface of the RFID tag, the first coating material having a first thickness over a portion of the first LC circuit, the first coating configured to permit a conductivity property of a fluid proximate the first outer surface to affect the first resonant frequency of the first LC circuit such that the first resonant frequency shifts to a second resonant frequency.

2. The RFID tag of claim 1, further comprising:

a second LC circuit including a second capacitive element coupled to a second inductive element, wherein the first coating material has a second thickness over a portion of the second LC circuit, the second thickness being different from the first thickness, the second thickness being such that the conductivity property of the fluid proximate the first outer surface does not affect a resonant frequency of the second LC circuit.

3. The RFID tag of claim 2, wherein the second LC circuit is formed on a second die, and wherein the second die is attached to the first die.

4. The RFID tag of claim 3, wherein the resonant frequency of the second LC circuit is substantially equal to the first resonant frequency.

5. The RFID tag of claim 4, wherein the tag has an increased read range compared to a tag having only a single die and a single LC circuit.

6. The RFID tag of claim 1, wherein

the first capacitive element includes a top electrode, a bottom electrode, and a dielectric layer between the top electrode and the bottom electrode, the dielectric layer including a material having a Young'"'"'s modulus within a range to maintain elastic behavior of the material when the first capacitive element is in operation, and

a compressibility property of the first coating material is such that pressure of the fluid proximate the first outer surface generates a change in a distance between the top electrode and the bottom electrode to generate a proportionate change in a capacitive value of the first capacitive element.

7. The RFID tag of claim 1, wherein the first capacitive element includes a top electrode, a bottom electrode, and a dielectric layer between the top electrode and the bottom electrode, the dielectric layer including a material having a coefficient of thermal expansion such that a change in temperature of fluid proximate the first outer surface generates a change in a distance between the top electrode and the bottom electrode to generate a proportionate change in a capacitive value of the first capacitive element.

8. The apparatus of claim 7, wherein the dielectric layer is non-compressible.

9. The apparatus of claim 7, wherein the top electrode includes a plurality of metal layers.

10. The apparatus of claim 9, wherein the plurality of metal layers includes a copper layer.

11. The RFID tag of claim 1, further comprising a second coating material, different from the first coating material, disposed around the first coating material to reduce abrasion effects on the RFID tag.

12. A system comprising:

a casing string having a communication assembly supported by the casing string, wherein the communication assembly is configured to obtain information associated with radio frequency identification (RFID) tags in an annulus surrounding the casing when the casing is in place within a borehole; and

a first plurality of RFID tags placed within a first fluid pumped into the annulus, each of the first plurality of RFID tags including,

a die attached to an inductive-capacitive (LC) circuit, the LC circuit having a first resonant frequency, and

a coating material disposed around the die to form an outer surface, the coating material having a thickness to permit a conductivity property of the first fluid to affect the first resonant frequency such that the first resonant frequency shifts to a shifted resonant frequency; and

a processor configured to receive data indicative of the shifted resonant frequency and to determine a property of the fluid based on the shifted resonant frequency.

13. The system of claim 12, further comprising a second plurality of RFID tags configured differently from the first plurality of RFID tags and placed within the first fluid to detect another property of the first fluid.

14. The system of claim 12, wherein the communication assembly includes a plurality of RFID sensor assemblies, each RFID sensor assembly arranged on the communication assembly to interrogate RFID tags within a selected azimuthal region of the annulus.

15. The system of claim 14, further comprising:

a memory device operably coupled to the processor, the memory device having stored thereon values representative of first resonant frequencies for each of the plurality of RFID tags and expected shifted resonant frequencies for each of the plurality of RFID tags; and

wherein

each RFID sensor assembly includes oscillator circuitry in communication with the memory and processor to provide interrogation frequencies, retrieved from the memory, to interrogate the RFID tags.

16. A method for monitoring wellbore conditions, the method comprising:

associating a sensor assembly with the exterior of a casing string being placed in a borehole, wherein the sensor assembly is configured to communicate with radio frequency identification device (RFID) tags in an annulus surrounding the casing when the casing is in place within the borehole;

pumping a fluid into the annulus, the fluid containing a plurality of RFID tags, each of the plurality of RFID tags having a first inductive-capacitive (LC) circuit with a first intrinsic resonant frequency, the plurality of RFID tags having an associated set of shifted resonant frequencies to which the first intrinsic resonant frequency shifts responsive to properties of the fluid;

providing, by the sensor assembly, a plurality of interrogation frequencies, the plurality of interrogation frequencies including each shifted resonant frequency of the set of shifted resonant frequencies and the first intrinsic resonant frequency of each of the plurality of RFID tags; and

detecting a property of the fluid upon receiving a signal with a first shifted resonant frequency, responsive to providing an interrogation frequency of the plurality of interrogation frequencies, from an RFID tag of the plurality of RFID tags.

17. The method of claim 16, further comprising:

detecting another property of the fluid upon receiving a signal at a second shifted resonant frequency different from the first shifted resonant frequency.

18. The method of claim 16, wherein at least one RFID tag of the plurality of RFID tags includes a second LC circuit with a second intrinsic resonant frequency, and the method further comprises:

detecting the first intrinsic resonant frequency of the first LC circuit of the at least one RFID tag to detect the presence of the at least one RFID tag, and, subsequent to detecting the presence, estimating a shifted resonant frequency of the second LC circuit of the at least one RFID tag to detect the property of the fluid.

19. An RFID tag, comprising,

an induction-capacitance circuit, including,

an inductor in the general form of a two dimensional helix expanding from a central region, the inductor having a first inner end and a second outer end, the first inner end extending from the central region,

a capacitor formed entirely within the central region, and having a first and second electrodes, the first capacitor electrode coupled to the first inner end of the inductor, and

a conductive link coupling the second outer end of the conductor to the second capacitor electrode;

an encapsulant surrounding the induction-capacitance circuit.

20. The RFID tag of claim 19, further comprising a substrate, and wherein the induction-capacitance circuit is formed on the substrate.