# US 10,309,218 B2 · Dielectric contrast agents and methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,218 B2 - Document ID: US10309218B2 - Status: Granted - Kind: B2 - Application number: 14/551,865 - Filed: 2014-11-24 - Published: 2015-06-18 - Granted: 2019-06-04 - Earliest claimed: 2012-05-31 - Assignees: The University of North Carolina at Chapel Hill; Board of Regents, The University of Texas System - Applicants: The University of North Carolina at Chapel Hill; Board of Regents, The University of Texas System - Inventors: Pabitra Sen; Alfred Kleinhammes; Yue Wu; Mohsen Ahmadian-Tehrani - Web page: https://patentgrep.com/patent/US10309218B2 ## CPC - E21B 49/087: {Well testing, e.g. testing for reservoir productivity or formation parameters} - E21B 47/114: {using light radiation} - E21B 47/13: by electromagnetic energy, e.g. radio frequency - G01V 3/30: operating with electromagnetic waves - E21B 47/002: by visual inspection - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) ## Abstract Contrast agents and methods for use in geological applications are provided. Contrast agents can be a nanopolymorph material, such as titania nanotubes, and have a low-frequency dielectric permittivity. Methods of identifying one or more subterranean features during geological exploration are provided. Methods of identifying a ganglion of bypassed oil are provided. Methods of illuminating subterranean fractures in hydraulic fracturing are provided. ## Claims ### Claim 1 A method of identifying a subterranean feature, comprising: administering a contrast agent into a geological site, wherein the contrast agent comprises a nanopolymorph material having a low-frequency dielectric permittivity, wherein the nanopolymorph material is a titania nanotube; allowing the contrast agent to migrate to a subterranean feature in the geological site; and illuminating the subterranean feature using an electromagnetic tool configured to sense a presence of the contrast agent based on the enhanced dielectric permittivity imparted by the contrast agent that has migrated to the subterranean feature. ### Claim 2 (depends on 1) The method of claim 1, wherein a dielectric permittivity of the contrast agent is greater than about 5,000 (F/m). ### Claim 3 (depends on 1) The method of claim 1, further comprising a membrane encapsulating the contrast agent. ### Claim 4 (depends on 3) The method of claim 3, wherein the membrane is configured to become permeable upon encountering a stimulus selected from the group consisting of pH, temperature, pressure, salinity, and combinations thereof. ### Claim 5 (depends on 3) The method of claim 3, wherein the membrane is configured to become permeable after a predetermined period of time has elapsed. ### Claim 6 (depends on 1) The method of claim 1, wherein the contrast agent is stable at a temperature up to about 350° C. and a pH ranging from about 1 to about 12. ### Claim 7 (depends on 1) The method of claim 1, wherein the sensing a presence of the contrast agent is performed as a function of a dielectric enhancement of the subterranean feature by the nanopolymorph material having the low-frequency dielectric permittivity. ### Claim 8 A method of identifying a ganglion of bypassed oil in a geological formation, comprising: administering a contrast agent into the geological formation, wherein the contrast agent comprises a nanopolymorph material having a low-frequency dielectric permittivity, wherein the nanopolymorph material is a titania nanotube, wherein the contrast agent migrates to the ganglion of bypassed oil in the geological formation; and illuminating the ganglion of bypassed oil using an electromagnetic tool configured to sense a presence of the contrast agent based on the enhanced dielectric permittivity imparted by the contrast agent that has migrated to the ganglion of bypassed oil. ### Claim 9 (depends on 8) The method of claim 8, wherein a dielectric permittivity of the contrast agent is greater than about 5,000 (F/m). ### Claim 10 (depends on 8) The method of claim 8, further comprising a membrane encapsulating the contrast agent, wherein the membrane is configured to become permeable upon encountering a stimulus selected from the group consisting of pH, temperature, pressure, salinity, and combinations thereof. ### Claim 11 (depends on 8) The method of claim 8, wherein the contrast agent is stable at a temperature up to about 350° C. and a pH ranging from about 1 to about 12. ### Claim 12 (depends on 8) The method of claim 8, wherein the contrast agent is configured to have an affinity toward an interface between water and oil. ### Claim 13 (depends on 8) The method of claim 8, wherein the sensing a presence of the contrast agent is performed as a function of a dielectric enhancement of the ganglion of bypassed oil by the nanopolymorph material having the low-frequency dielectric permittivity. ### Claim 14 A method of illuminating a subterranean fracture, comprising: administering a contrast agent into the subterranean fracture, wherein the contrast agent comprises a titania nanotube having a low frequency dielectric permittivity greater than about 5,000 (F/m); and illuminating the subterranean fracture using an electromagnetic tool configured to sense a presence of the contrast agent based on the enhanced dielectric permittivity imparted by the contrast agent. ### Claim 15 (depends on 14) The method of claim 14, further comprising a membrane encapsulating the contrast agent, wherein the membrane is configured to become permeable upon encountering a stimulus selected from the group consisting of pH, temperature, pressure, salinity, and combinations thereof. ### Claim 16 (depends on 14) The method of claim 14, wherein the contrast agent is stable at a temperature up to about 350° C. and a pH ranging from about 1 to about 12. ### Claim 17 (depends on 14) The method of claim 14, wherein the titania nanotube has the low frequency permittivity greater than about 5,000 (F/m) when in the presence of brine within the subterranean fracture. ### Claim 18 A method of identifying a subterranean feature, comprising: administering a contrast agent into a geological site, wherein the contrast agent comprises a nanopolymorph material having a low-frequency dielectric permittivity, wherein the nanopolymorph material is a titania nanotube; allowing the contrast agent to migrate to a subterranean feature in the geological site; and illuminating the subterranean feature using an electromagnetic tool configured to sense a presence of the contrast agent based on the enhanced dielectric permittivity imparted by the contrast agent that has migrated to the subterranean feature, wherein the titania nanotube comprises an exchangeable Na+. ### Claim 19 A method of identifying a ganglion of bypassed oil in a geological formation, comprising: administering a contrast agent into the geological formation, wherein the contrast agent comprises a nanopolymorph material having a low-frequency dielectric permittivity, wherein the nanopolymorph material is a titania nanotube, wherein the contrast agent migrates to the ganglion of bypassed oil in the geological formation; and illuminating the ganglion of bypassed oil using an electromagnetic tool configured to sense a presence of the contrast agent based on the enhanced dielectric permittivity imparted by the contrast agent that has migrated to the ganglion of bypassed oil, wherein the titania nanotube comprises an exchangeable Na+. ### Claim 20 A method of illuminating a subterranean fracture, comprising: administering a contrast agent into the subterranean fracture, wherein the contrast agent comprises a titania nanotube having a low-frequency dielectric permittivity greater than about 5,000 (F/m); and illuminating the subterranean fracture using an electromagnetic tool configured to sense a presence of the contrast agent based on the enhanced dielectric permittivity imparted by the contrast agent, wherein the titania nanotube comprises an exchangeable Na+.