Monitoring of Wells to Detect the Composition of Matter in Boreholes and Propped Fractures

• US 20130328693A1
• Filed: 04/26/2013
• Published: 12/12/2013
• Est. Priority Date: 04/26/2012
• Status: Active Grant

• Current Assignee: Farrokh Mohamadi
• Original Assignee: Farrokh Mohamadi
• Inventors: Mohamadi, Farrokh
• Granted Patent: US 9,201,157 B2
• Time in Patent Office: Days
• US Class Current: 340/854.6
• CPC Class Codes: E21B 43/267 reinforcing fractures by propping
• CPC Class Codes: E21B 47/11 using tracers; using radioactivity
• CPC Class Codes: E21B 47/13 by electromagnetic energy, e.g. radio frequency
• CPC Class Codes: G01V 3/30 operating with electromagnetic waves

Abstract

There is provided a system and method for monitoring of fractured wells and conventional wells to detect leaks. The method comprises interrogating a plurality of resonant tags using a modulated RF signal transmitted from an interrogator, wherein the plurality of resonant tags are dispersed within a channel.

Claims

1. A system comprising:

a processor; and

an interrogator configured to interrogate a channel associated with an oil well borehole using a frequency-modulated RF signal such that the frequency-modulated RF signal covers an expected range of resonant frequencies for resonant tags within the channel, and wherein the processor is configured to characterize a dielectric constant for a medium in the channel using resonant reflections received by the interrogator from the resonant tags in the channel.

2. The system of claim 1, wherein the processor is further configured to determine a composition for matter filling the channel based upon the characterized dielectric constant.

3. The system of claim 2, wherein the processor is further configured to map a location for the resonant tags in a propped fracture adjacent the borehole.

4. The system of claim 1, further comprising the resonant tags, wherein each resonant tag further comprises:

a cylindrical array comprising a plurality of structures arranged to form a second hollow cylinder;

a dielectric material configured to fill the second hollow cylinder; and

a covering material configured to encapsulated the filled cylindrical array such that the resonant tag has a size approximating the size of a proppant.

6. The system of claim 1, wherein the interrogator is configured to beamform the frequency-modulated RF signal.

5. The system of claim 5, wherein the resonant tag is configured to be resonant in the terahertz region.

8. A method comprising:

interrogating a channel using a frequency-modulated RF signal transmitted from an interrogator such that the frequency-modulated RF signal covers an expected range of resonant frequencies for interrogated resonant tags within the channel;

determining a strength for reflected resonant signals from the interrogated resonant tags; and

characterizing a dielectric constant for a material filling the channel using the determined signal strengths.

7. The system of claim 8, wherein the interrogator is configured to beamsteer the frequency-modulated RF signal.

9. The method of claim 8, further comprising determining a composition for the material using the characterized dielectric constant.

10. The method of claim 8, further comprising:

determining the composition of matter for a plurality of propped fractures using the characterized dielectric constant; and

detecting a propped fracture having an anomalous composition of matter compared to remaining ones of the propped fractures.

11. A method, comprising:

advancing an interrogator through an oil well borehole to sampled locations within the borehole, wherein the borehole includes a well casing having a plurality of resonant tags lining a borehole-facing wall for the well casing;

at each sampled location, interrogating resonant tags at the sampled location to characterize a dielectric constant for a channel between the interrogator and the interrogated resonant tags at the sampled location; and

based upon the characterized dielectric constants for the channels at the sampled locations, determining whether the well casing is compromised.

12. The method of claim 11, wherein determining whether the well casing is compromised includes determining whether the characterized dielectric constants indicate the presence of water within the borehole.

13. The method of claim 11, wherein interrogating the resonant tags at each sampled location includes interrogating the resonant tags with a frequency-modulated RF signal.

14. The method of claim 11, wherein characterizing the dielectric constant comprises measuring a received resonant signal reflected from the interrogated resonant tags.