# US 4,397,190 A · Apparatus and method for determining flow characteristics of a fluid > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,397,190 A - Document ID: US4397190A - Status: Granted - Kind: A - Application number: 06/217,620 - Filed: 1980-12-18 - Granted: 1983-08-09 - Earliest claimed: 1979-12-28 - Assignees: Schlumberger Technology Corporation - Inventors: Jean-Pierre Hulin - Web page: https://patentgrep.com/patent/US4397190A ## CPC - G01F 1/34: by measuring pressure or differential pressure - G01F 1/712: using auto-correlation or cross-correlation detection means - G01P 5/14: by measuring differences of pressure in the fluid - G01P 5/18: by measuring the time taken to traverse a fixed distance - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) ## Abstract A method and apparatus for determining the flow rate and other flow characteristics of a polyphase fluid or a turbulent single-phase fluid flowing in a conduit are disclosed. Two differential pressure sensors are provided, each having two pressure ports sensitive to local pressure variation in the fluid. The pressure ports are maintained in a predetermined spatial relationship and in a predetermined orientation relative to the general direction of the flow. The detection signals from the respective sensors are correlated to obtain the flow rate. Additionally, a selected one of the detection signals is processed to obtain other flow characteristics. One of these other flow characteristics, the type of flow, is useful in facilitating the determination of the flow rate. ## Claims ### Claim 1 An apparatus for producing signals indicative of at least one flow characteristic of a polyphase or turbulent single-phase fluid flowing in a well, comprising: a first differential pressure sensor, including a differential pressure transducer and two sensitive points each responsive to local pressure variation in said fluid, for obtaining a detection signal representative of the instantaneous fluctuations of the pressure gradient in a portion of said fluid therebetween; a second differential pressure sensor, including a differential pressure transducer and two sensitive points each responsive to local pressure variation in said fluid, for obtaining a detection signal representative of the instantaneous fluctuations of the pressure gradient in a portion of said fluid therebetween; and an elongated support structure, adapted for displacement in the well, to which the sensitive points of said first and second sensors are fixedly connected: in a linear arrangement substantially parallel to the direction of fluid flow and within a core portion of said fluid flow; and at respective levels separated by consecutive intervals, a first median level being defined intermediate the respective levels of the sensitive points of said first sensor and a second median level being defined intermediate the respective levels of the sensitive points of said second sensor; the distance between said first median level and said second median level being no less than one-third the length of one of said consecutive intervals that is no smaller than any other of said consecutive intervals; and the distance between said first median level and said second median level being between a half-diameter and one diameter of the well. ### Claim 2 (depends on 1) An apparatus as in claim 1, wherein the sum of the lengths of said consecutive intervals is no less than an expected size of large phase domains along the direction of fluid flow. ### Claim 3 An apparatus for producing signals indicative of at least one flow characteristic of a polyphase or turbulent single-phase fluid flowing in a well, comprising: a first differential pressure sensor, including a differential pressure transducer and two sensitive points each responsive to local pressure variation in said fluid, for obtaining a detection signal representative of the instantaneous fluctuations of the pressure gradient in a portion of said fluid therebetween; a second differential pressure sensor, including a differential pressure transducer and two sensitive points each responsive to local pressure variation in said fluid, for obtaining a detection signal representative of the instantaneous fluctuations of the pressure gradient in a portion of said fluid therebetween; and an elongated support structure, adapted for displacement in the well, to which the sensitive points of said first and second sensors are fixedly connected at respective levels separated by consecutive intervals; at least one of said consecutive intervals being a heterogeneous interval no greater than one-half the distance between the two sensitive points of each of said first and second differential pressure sensors. ### Claim 4 (depends on 3) An apparatus as in claim 3, wherein any of said consecutive intervals that is a heterogeneous interval and greater in length than a smallest one of said consecutive intervals, is no less than twice the length thereof. ### Claim 5 (depends on 4) An apparatus as in claim 4, wherein a smallest one of said consecutive intervals is a heterogeneous interval of a length no greater than ten times an expected average size of small phase domains along the direction of flow. ### Claim 6 An apparatus for producing signals indicative of at least one flow characteristic of a polyphase or turbulent single-phase fluid flowing in a well, comprising: a first differential pressure sensor, including a differential pressure transducer and two sensitive points each responsive to local pressure variation in said fluid, for obtaining a detection signal representative of the instantaneous fluctuations of the pressure gradient in a portion of said fluid therebetween; a second differential pressure sensor, including a differential pressure transducer and two sensitive points each responsive to local pressure variation in said fluid, for obtaining a detection signal representative of the instantaneous fluctuations of the pressure gradient in a portion of said fluid therebetween; and an elongated support structure, adapted for displacement in the well, to which the sensitive points of said first and second sensors are fixedly connected: in a linear arrangement substantially parallel to the direction of fluid flow and within a core portion of said fluid flow; and at respective levels separated by consecutive intervals, a first median level being defined intermediate the respective levels of the sensitive points of said first sensor and a second median level being defined intermediate the respective levels of the sensitive points of said second sensor; the distance between said first median level and said second median level being no less than one-third the length of one of said consecutive intervals that is no smaller than any other of said consecutive intervals; the distance between said first median level and said second median level being between a half-diameter and one diameter of the well; and at least one of said consecutive intervals being a heterogeneous interval no greater than one-half the distance between the two sensitive points of each of said first and second differential pressure sensors. ### Claim 7 (depends on 6) An apparatus as in claim 6, wherein any of said consecutive intervals that is a heterogeneous interval and greater in length than a smallest one of said consecutive intervals, is no less than twice the length thereof. ### Claim 8 (depends on 7) An apparatus as in claim 7, wherein a smallest one of said consecutive intervals is a heterogeneous interval of a length no greater than ten times an expected average size of small phase domains along the direction of flow. ### Claim 9 (depends on 8) An apparatus as in claim 8, wherein: an intermediate one of said consecutive intervals is a heterogeneous interval no greater than one-fourth the length of the other of said consecutive intervals respectively; and said first interval and said second interval are of equal length. ### Claim 10 (depends on 9) An apparatus as in claim 9, wherein an intermediate one of said consecutive intervals is the only heterogeneous interval. ### Claim 11 (depends on 6) An apparatus as in claim 6, wherein: an intermediate one of said consecutive intervals is a heterogeneous interval no greater than one-half the length of the other of said consecutive intervals respectively; and said first interval and second interval are of equal length.