# US 8,784,068 B2 · System and method for sensing a liquid level > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,784,068 B2 - Document ID: US8784068B2 - Status: Granted - Kind: B2 - Application number: 13/726,515 - Filed: 2012-12-24 - Published: 2013-05-02 - Granted: 2014-07-22 - Earliest claimed: 2009-10-05 - Assignees: Chevron U.S.A. Inc. - Applicants: Chevron U.S.A., Inc. - Inventors: M. Clark Thompson; Charles H. Webb - Web page: https://patentgrep.com/patent/US8784068B2 ## CPC - G01F 23/22: by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water (involving the use of floats G01F23/30) - E21B 47/047: Liquid level (measuring depth or liquid level using radioactive markers E21B47/053) - F04B 47/00: Pumps or pumping installations specially adapted for raising fluids from great depths, e.g. well pumps (by using positive or negative pressurised fluid medium acting directly on the liquid to be pumped F04F1/00) - F04B 49/065: {and making use of computers} - G01F 23/284: Electromagnetic waves - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) ## Abstract A system, method and device may be used to monitor fluid levels in a borehole. The system includes a pulse generator to generate a pulse of electromagnetic energy to propagate along the wellbore towards a surface of the fluid, a detector to detect a portion of the electromagnetic pulse reflected from the surface of the fluid and propagated along the wellbore towards the detector, a processor to analyze detected signals to determine a level of the surface of the fluid, and a pump controller to control the operation of a pump located in the wellbore based on the fluid surface level. ## Claims ### Claim 1 A system for measuring a fluid level in a casing-lined wellbore, comprising: a pulse generator, positionable and operable to generate a pulse of electromagnetic energy to propagate along the wellbore towards a surface of the fluid; a detector, positionable and operable to detect a portion of the electromagnetic pulse reflected from the surface of the fluid and propagated along the wellbore towards the detector; a processor, configured and arranged to receive a signal from the detector representative of the detected portion of the electromagnetic pulse and to analyze it to determine a level of the surface of the fluid; and a pump controller, configured and arranged to receive distance information from the processor and to use the distance information to control the operation of a pump located in the wellbore and wherein once the detector detects the portion of electromagnetic pulse reflected from the surface, reception of the signal is inhibited. ### Claim 2 (depends on 1) A system as in claim 1, wherein the pump controller reduces pump capacity when the distance information indicates that the fluid level is near a pump level in the wellbore. ### Claim 3 (depends on 1) A system as in claim 1, wherein the pump controller stops the pump when the distance information indicates that the fluid level is at or below a pump level in the wellbore. ### Claim 4 (depends on 1) A system as in claim 1, wherein the pump controller increases pump capacity when the distance information indicates that the fluid level is at a level greater than a selected amount greater than the pump level. ### Claim 5 (depends on 1) A system as in claim 1, wherein the processor is further configured and arranged to analyze the signals to obtain information relating to a composition of the fluid based on an amplitude of the detected portion. ### Claim 6 (depends on 5) A system as in claim 5, wherein the composition information comprises a proportion of water to hydrocarbon. ### Claim 7 (depends on 1) A system as in claim 1, wherein a rate of change of successive distance information measurements is used to determine whether the fluid level is rising or falling, and the pump controller further controls the operation of the pump based on the direction of change of the fluid level. ### Claim 8 (depends on 1) A system as in claim 1, wherein a rate of change of successive distance information measurements is used to determine whether the fluid level is rising or falling, and the pump controller further controls the operation of the pump based on a magnitude of change of the fluid level. ### Claim 9 (depends on 1) The system as in claim 1 wherein the detector is configured to be powered on during a time window delayed with respect to the generation of electromagnetic energy. ### Claim 10 A method for controlling a pump located in a casing-lined wellbore, comprising: generating a pulse of electromagnetic energy to propagate along the wellbore towards a surface of the fluid; detecting with a detector a portion of the electromagnetic pulse reflected from the surface of the fluid and propagated along the wellbore towards the detector; receiving a signal from the detector representative of the detected portion of the electromagnetic pulse; analyzing the signal to determine a level of the surface of the fluid; and controlling the operation of the pump, based on the determined surface level of the fluid wherein once the detector detects the portion of electromagnetic pulse reflected from the surface, reception of the signal is inhibited. ### Claim 11 (depends on 10) A method as in claim 10, wherein the controlling comprises reducing pump capacity when the determined surface level is near a pump level in the wellbore. ### Claim 12 (depends on 10) A method as in claim 10, wherein the controlling comprises stopping the pump when the distance information indicates that the fluid level is at or below a pump level in the wellbore. ### Claim 13 (depends on 10) A method as in claim 10, wherein the controlling comprises increasing pump capacity when the distance information indicates that the fluid level is at a level greater than a selected amount greater than the pump level. ### Claim 14 (depends on 10) A method as in claim 10, further comprising determining information relating to a composition of the fluid based on an amplitude of the detected portion. ### Claim 15 (depends on 14) A method as in claim 14, wherein the composition information comprises a proportion of water to hydrocarbon. ### Claim 16 (depends on 10) A method as in claim 10, wherein the controlling further comprises controlling the operation of the pump based on a direction of change of the fluid level over successive measurements. ### Claim 17 (depends on 10) A method as in claim 10, wherein the controlling further comprises controlling the operation of the pump based on a magnitude of change of the fluid level over successive measurements. ### Claim 18 (depends on 10) The method as in claim 10, wherein the detector is configured to be powered on during a time window delayed with respect to the generation of electromagnetic energy.