The “Why & When of Flow Metering Systems”

In oil and gas industry, what matters most is the inflow and outflow of production. Oil&Gas needs to be measured, controlled and managed to ensure accuracy and to avoid critical loss – this brings about the basics of flow metering.


A typical flow meter is a device or instrument used to measure the rate of flow or quantity of a gas or liquid moving through a pipe or line. Flow meter is an important section of virtually every oil & gas operation.


As important flow metering is, if not checked and corrected for accuracy, it can lead to a revenue losses or custody allocation. At gathering facilities where custody of tens of millions of gallons of product is transferred from one party to another on a daily basis, their role is mission-critical.

Consider, for example, a gathering station that pumps 10,000 gallons of crude oil per minute. A flow measurement error of just 0.02% (under what is actually being pumped) will result in the loss of 68 barrels per day. Say a barrel goes for $40 per, that result into nearly $1 million per year. Going for proactive steps to ensure metering perform accurately and reliably is major precaution to avoiding this.


  • Installation: The first, and perhaps most important, action to help prevent measurement inaccuracy is to make sure that instrumentation is properly calibrated before it is put into operation.
  • Periodically: Because flow meters are often in continuous use, drifting can also be a serious problem. Periodic meter proving is essential to identifying drift and correcting it.  Flow meters indicate volume by producing pulses in proportion to the amount of fluid that passes through them. Meter proving is a type of calibration that uses this concept to determine accuracy by comparing a known volume of liquid passed through a prover to the volume indicated by the flow meter being tested.  The data obtained during the proving test is used to calculate a correction, which allows operators to adjust meter readings so that they are representative of true flow rates.
  • Routine meter proving / calibration also helps protect against measurement inaccuracies arising from natural mechanical wear, product build up, pipe blockages, and changes to the properties of the product flowing through the line.


  • GIL Automation is certified in line with ISO17025 requirements to provide both primary and secondary calibration services for pneumatic, hydraulic and electronic instruments. We are certified by local standard boards and we provide primary metering systems for proving meters.
  • GIL Automation offers on-site and in-house flow meter calibration for a wide range of petroleum-based products. Our truck-mounted volumetric proving vessels, with capacities ranging up to 5000 liters and a wide range of master masters are available for on-site flow meter calibration of petroleum products and some chemicals. We also have capabilities in flow metering related to fiscal metering, custody transfer etc. All our metering jobs are done to industrial accepted standards.

Gil Automation with her trained personnel had in past provided this service to several clients without slip. Also, in conjunction with her technical partners, GIL provides/supports metering skids, wellhead control panel, Hydraulic Power Units, Dosing Systems, LACT units, Gas Analyzer shelters, Meter provers and ESD skids.

For more information about us please visit or call 0700-AUTOMATION/01-440-6296 or e-mail

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