PROCEDURE FOR AUTOMATIC CONTROL OF FLUID FLOW RATE Russian patent published in 2011 - IPC E21B47/10 E21B44/00 

FIELD: oil and gas production.

SUBSTANCE: procedure for automatic control of fluid flow rate, mainly, drilling agents and grouting mortars, by means of super-sonic Doppler flow metre consists in calibrating flow metre on calibration rig with one point of scale by scaling its indications to indications of scale of reference instrument. Further, there is measured rate of fluid flow in a controlled pump main; results of control are processed with a computer. Also, before calibration two portions of fluid are prepared with minimal and close to maximal values of density within the ranges of its allowed variations. On the calibrating rig and using fluid of less density there is created flow with rate close to average value of a measurement range. There is obtained a calibrating characteristic in the accepted scale; this characteristic is obtained in form of directly proportional functional dependency with coefficient of proportionality equal to one. Further, this operation is repeated with the second portion of fluid. By the obtained calibrating characteristic of the flow metre there is determined flow rate. This value together with source data accepted in calibrating process is saved in memory of the computer for performing successive mathematic operations. Current value of fluid flow rate in the pump main is measured depending on determined current value of fluid density in it, while actual rate of flow is established by a reduced mathematical expression.

EFFECT: increased accuracy of measurement at control over drilling and grouting processes.

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