# US 10,865,640 B2 · Downhole tool with CATR > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,865,640 B2 - Document ID: US10865640B2 - Status: Granted - Kind: B2 - Application number: 16/380,806 - Filed: 2019-04-10 - Published: 2020-10-15 - Granted: 2020-12-15 - Earliest claimed: 2019-04-10 - Assignees: Saudi Arabian Oil Company - Applicants: Saudi Arabian Oil Company - Inventors: Jose Oliverio Alvarez - Web page: https://patentgrep.com/patent/US10865640B2 ## CPC - E21B 47/10: Locating fluid leaks, intrusions or movements - E21B 49/003: {by analysing drilling variables or conditions (E21B49/005 takes precedence; systems specially adapted for monitoring a plurality of drilling variables or conditions E21B44/00)} - E21B 47/13: by electromagnetic energy, e.g. radio frequency - E21B 47/14: using acoustic waves - G01R 29/105: {using anechoic chambers; Chambers or open field sites used therefor (test sites used for measuring on other objects than aerials G01R29/0828; wave absorbing devices H01Q17/00)} - G01V 3/30: operating with electromagnetic waves - H04B 17/29: Performance testing - G01V 1/50: Analysing data - G01V 2200/16: Measure-while-drilling or logging-while-drilling - G01V 2210/6169: using well-logging - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) - H04B: TRANSMISSION ## Abstract A system, downhole tool, and method for lowering the downhole tool having a compact antenna test range (CATR) system into a wellbore in a geological formation to monitor a property downhole in the wellbore via the downhole tool. ## Claims ### Claim 1 A method of downhole monitoring, comprising: lowering a downhole tool comprising a compact antenna test range (CATR) system into a wellbore in a geological formation; monitoring a property downhole in the wellbore via the downhole tool; and detecting a gas kick via the monitoring of the property. ### Claim 2 (depends on 1) The method of claim 1, wherein the property comprises permittivity, and wherein the CATR system comprises a metallic reflector comprising edge treatment. ### Claim 3 (depends on 1) The method of claim 1, wherein the CATR system comprises a source antenna, a metal reflector, a receiver antenna, and EM radiation absorbent material. ### Claim 4 (depends on 1) The method of claim 1, wherein monitoring the property downhole comprises: emitting EM waves via a source antenna of the CATR system; and reflecting the EM waves via a metal reflector of the CATR system, wherein direction of reflected EM plane waves is parallel with flow of wellbore fluid in the wellbore. ### Claim 5 (depends on 4) The method of claim 4, and wherein the property comprises complex permittivity of the wellbore fluid, and wherein the wellbore fluid comprises drilling fluid or production fluid. ### Claim 6 (depends on 1) The method of claim 1, wherein monitoring the property downhole comprises emitting EM waves via a source antenna of the CATR system, the EM waves comprising microwave range or millimeter range, or a combination thereof. ### Claim 7 (depends on 1) The method of claim 1, wherein the property comprises a geological formation property, wherein a metal reflector of the CATR system faces toward the geological formation, and wherein monitoring the property comprises emitting EM waves via a source antenna of the CATR system and reflecting the EM waves via the metal reflector toward the geological formation. ### Claim 8 A method of downhole monitoring, comprising: lowering a downhole tool comprising a compact antenna test range (CATR) system into a wellbore in a geological formation; and monitoring a property of a wellbore fluid downhole in the wellbore via the downhole tool, wherein direction of reflected electromagnetic (EM) plane waves in the CATR is parallel or perpendicular to flow of the wellbore fluid in the wellbore. ### Claim 9 A method of downhole monitoring, comprising: deploying a downhole tool comprising a compact antenna test range (CATR) system into a wellbore in a geological formation, wherein the CATR system comprises a source antenna, a metallic reflector, a receiver antenna, and electromagnetic (EM) radiation absorbent material; monitoring permittivity downhole in the wellbore via the downhole tool; detecting a gas kick via the monitoring of the permittivity; and sending an alert via the downhole tool in response to detecting the gas kick. ### Claim 10 (depends on 9) The method of claim 9, wherein the permittivity comprises relative permittivity, and wherein the metallic reflector comprises edge treatment. ### Claim 11 (depends on 9) The method of claim 9, wherein monitoring permittivity downhole comprises emitting EM waves via the source antenna at microwave range or millimeter range, or a combination thereof. ### Claim 12 (depends on 9) The method of claim 9, wherein monitoring permittivity downhole comprises measuring permittivity of wellbore fluid downhole via the CATR system. ### Claim 13 (depends on 9) The method of claim 9, wherein monitoring permittivity downhole comprises measuring permittivity of the geological formation via the CATR system. ### Claim 14 A downhole tool comprising: a body; a coupler to connect the body to a deployment extension that lowers the downhole tool into the wellbore; a compact antenna test range (CATR) system associated with the body to measure permittivity downhole in the wellbore, wherein the CATR system comprises a source antenna, a metallic reflector, a receiver antenna, and electromagnetic (EM) radiation absorbent material and a processor to detect a gas kick via the CATR system and to send an alert of the gas kick. ### Claim 15 (depends on 14) The downhole tool of claim 14, wherein the source antenna to emit EM waves in microwave range or millimeter range, or a combination thereof. ### Claim 16 (depends on 14) The downhole tool of claim 14, wherein the deployment extension comprises a wireline or coiled tubing. ### Claim 17 (depends on 14) The downhole tool of claim 14, wherein the CATR system comprises an anechoic chamber comprising the EM radiation absorbent material. ### Claim 18 (depends on 17) The downhole tool of claim 17, wherein the EM radiation absorbent material comprises wedge shapes or pyramid shapes. ### Claim 19 (depends on 14) The downhole tool of claim 14, wherein the metallic reflector comprises edge treatment, and wherein the metallic reflector comprises a parabolic reflector or a hyperbolic reflector. ### Claim 20 (depends on 19) The downhole tool of claim 19, wherein the edge treatment comprises a serrated edge or a rolled edge, or a combination thereof. ### Claim 21 A downhole tool, comprising: a body; a coupler to connect the body to a deployment extension that lowers the downhole tool into the wellbore; and a compact antenna test range (CATR) system associated with the body to measure permittivity downhole in the wellbore, wherein the CATR system comprises a source antenna, a metallic reflector, a receiver antenna, and electromagnetic (EM) radiation absorbent material, wherein the receiver antenna is disposed in a plane wave zone comprising a quiet zone of the CATR system.