# US 7,607,361 B2 · Sonar circumferential flow conditioner > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,607,361 B2 - Document ID: US7607361B2 - Status: Granted - Kind: B2 - Application number: 12/035,578 - Filed: 2008-02-22 - Published: 2009-08-27 - Granted: 2009-10-27 - Earliest claimed: 2008-02-22 - Assignees: Weatherford/Lamb, Inc. - Inventors: Omer Haldun Unalmis; Espen S. Johansen; Leslie Wayne Perry; Alejandro Vera; Daniel Rodriguez; Vijay Ramakrishnan - Web page: https://patentgrep.com/patent/US7607361B2 ## CPC - G01F 1/708: Measuring the time taken to traverse a fixed distance - G01F 1/74: Devices for measuring flow of a fluid or flow of a fluent solid material in suspension in another fluid - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME ## Abstract Methods and apparatus enable measuring flow of a fluid within a conduit. For example, flowmeters may measure the velocity of production fluid flowing through production pipe of an oil/gas well. The flowmeters rely on detection of pressure variations generated as a result of a backward-facing step as a basis for flow measurement calculations. Pressure sensing occurs away from the step in a direction of the flow of the fluid in an enhanced turbulence region of the flowmeter where the inner diameter remains enlarged as a result of the step. ## Claims ### Claim 1 An apparatus for detecting pressure variations within a fluid that is flowing, comprising: a conduit containing the fluid, wherein a first section of the conduit has a first inner diameter and a second section of the conduit has a second inner diameter larger than the first inner diameter to define between the first and second sections a backward-facing step that produces the pressure variations; and an array of pressure sensors to sense the pressure variations, wherein the sensors are spaced along a length of the second section with the second inner diameter. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the backward-facing step has a shape that produces the pressure variations with multiple frequencies at any single given flow rate. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the shape of the backward-facing step is uniform and continuous around an entire circumference of the conduit. ### Claim 4 (depends on 1) The apparatus of claim 1, wherein the first section of the conduit is located between the step and a converging inner diameter portion of the conduit that gradually reduces a primary inner diameter of the conduit to the first inner diameter at the first section. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein the converging inner diameter portion is a nozzle. ### Claim 6 (depends on 4) The apparatus of claim 4, wherein the primary inner diameter is larger than the second inner diameter. ### Claim 7 (depends on 4) The apparatus of claim 4, further comprising a differential pressure sensing meter to measure a difference in pressure between first and second ports disposed on each side of the converging inner diameter portion. ### Claim 8 (depends on 1) The apparatus of claim 1, further comprising signal interface circuitry configured to measure a velocity of the fluid based on signals from the array of pressure sensors. ### Claim 9 (depends on 1) The apparatus of claim 1, wherein the array of pressure sensors include coils of optical fiber wrapper around an exterior of the conduit. ### Claim 10 (depends on 1) The apparatus of claim 1, wherein the array of pressure sensors include piezoelectric based detectors. ### Claim 11 (depends on 1) The apparatus of claim 1, wherein the array of pressure sensors are located within one meter of the step. ### Claim 12 A method of detecting pressure variations within a fluid that is flowing in a conduit in order to measure a velocity of the fluid, comprising: introducing the pressure variations into the fluid with a backward-facing step formed by an enlargement in an inner diameter of the conduit in a direction of fluid flow; reducing turbulence in the fluid with a converging inner diameter portion of the conduit prior to introducing the pressure variations, wherein the inner diameter is gradually reduced from a primary diameter ahead of the converging inner diameter portion to a first diameter prior to the enlargement at the step to a second diameter that is smaller than the primary diameter; sensing the pressure variations with an array of pressure sensors at spaced locations along a length of the conduit where the inner diameter remains enlarged past the step; and calculating the velocity of the fluid based on the pressure variations that are sensed. ### Claim 13 (depends on 12) The method of claim 12, further comprising measuring a differential pressure between upstream and downstream of the converging inner diameter portion. ### Claim 14 (depends on 12) The method of claim 12, wherein a dynamic pressure of the fluid is less than 500 pascals. ### Claim 15 A system for detecting pressure variations within a fluid for measuring flow of the fluid, comprising: a conduit containing the fluid, wherein a first section of the conduit is located between a second section of the conduit and a converging inner diameter portion of the conduit that gradually reduces a primary inner diameter of the conduit to a first inner diameter at the first section, which first section transitions to the second section that has a second inner diameter larger than the first inner diameter; an array of pressure sensors to sense the pressure variations, wherein the sensors are spaced along a length of the second section with the second inner diameter; and signal interface circuitry configured to measure a velocity of the fluid based on signals from the array of pressure sensors. ### Claim 16 (depends on 15) The system of claim 15, further comprising a differential pressure sensing meter to measure a difference in pressure between first and second ports disposed on each side of the converging inner diameter portion. ### Claim 17 (depends on 16) The system of claim 16, further comprising a water-in-liquid ratio meter. ### Claim 18 (depends on 15) The system of claim 15, further comprising a water-in-liquid ratio meter. ### Claim 19 (depends on 15) The system of claim 15, wherein the primary inner diameter is larger than the second inner diameter. ### Claim 20 (depends on 15) The system of claim 15, wherein the velocity is measurable at dynamic pressures of the fluid as low as 100 Pa.