The Design of an Independent Calibration Facility and its

Commissioning Using a Multi-path USM

Tom Ballard GE

T. Cousins CEESI

Introduction

• Introduction: Discussion about the need for good calibration for liquid meters.

• Description of calibration facility

• Description of operation of GE 4 path meter

• Calibration of the Turbine Master meters and USM

• Discussion of things that can go wrong and did with the calibration laboratory –valves, software etc.

• Show how we used the third party meter to help detect the issues, got some great graphs showing the issues.

• Conclusions

Is Measurement Less Important at $30/barrel?

• In absolute terms the losses are of less value!!

• But look at the effect on profit!!!

Price/barrel $ Production Cos/Barrelt $ Margin $

0.2% Uncertainty

on Basic

Volume/barrel

Error in

Margin %

100 20 80 0.2 0.25

30 20 10 0.06 0.6

Reynolds Number

• Many manufacturers calibrate their meters on water. • Water is a much easier process fluid to produce calibration facilities resulting

in cheaper calibration of meters.

• Very little thought has been given to the fact that many meters are not linear over their operational range: • Particularly with regard to Reynolds number

• Water calibrations do not represent the true nature of the meter performance on site, particularly if the fluid is oil.

• Constructing and operating oil facilities that can really simulate the Reynolds number operation on site is expensive.

• Note all meters are controlled by Reynolds Number!!

Reynolds Number-Water Vs Oil Calibration

Effect of Incorrectly Calibrated Meters

• The major results of not calibrating meters correctly • Are potentially large, in terms of uncertainty, errors in installed meters.

• Even with on site proving the results can be confusing and wrong.

• Water calibration can lead to corrections using extrapolation.

• It has taken many years to understand that many Coriolis meter designs are effected by Reynolds number, largely due to the lack of appropriate independent calibration

Linearisation/Data Fitting

• Meters that are often assumed to be linear throughout their range because a theory shows them to be independent of any issues: • it is only when independent testing is carried out that eventually this is often

found not to be true.

• The “black box” concept is used to hide the extent of the non-linearity.

• Both can lead to the customer/user, having a false view of the meter performance, • At the extreme incurring large uncertainties that he is not including in his

overall uncertainty budget: • Hence affecting his metering balances. • And even profitability.

Flowrate (Velocity) Vs Reynolds Number Calibration-Coriolis Meter

Calibration Difference using Low viscosity Fluid to calibrate and Fitting with a Polynomial Equation

Actual Calibration

4th Power Polynomial based on low viscosity fluid calibration.

Flow meter for Commissioning Facility

• Why do we need a “Check meter” for Commissioning? • It is needed so be able to determine the viability of operation of the facility. • It is needed to confirm the reproducibility of all the facility operations

• The proving • Master metering of all variations

• It is needed as a consistent standard for calibration.

• What are the attributes needed? • Large flow range • Consistent operation • Reproducible calibration (trustworthy)

• We chose a USM because: • We new the expected performance. • Low pressure drop. • Large Flow range • Free!!!

Design of USM

• The standard 4 path method is to use the Gaussian distribution.

• The different solutions give a non-linear calibration curve that has to be corrected.

• The GE design uses a combination of: • A theoretical solution using basic aerodynamics.

• Optimized by experiment.

Optimized Chord Locations

• Optimizations were made in the design to overcome limitations of Gaussian quadrature methods

• Development approach using symmetrical simulation methods of flow profiles • Reduced dependence on Reynolds through profile variations

Single K Factor Equation:

Modeled by Chord Location vs. Reynolds:

USM Design

Focus on factors for Linearity

• 4 Path Configuration

• Chord Placement – GE uses optimized locations (patented)

• Chord Weight Factors – empirical test

• Reproducible Cast Body – no welds

• Small Port sizes = less port effects

• Slight Taper Bore

• Simplified, Stable Electronics

Oil Calibration Facilioty Design

CEESI Multi-Viscosity calibration facility

Heat Exchanger

Specification • It uses known and proven measurement methods-9 months from design to first accreditation.

• ISO 17025

• Sealed System with pressure stabilization.

• Size range – 1”-12” Full flow – Two Systems.

• Base calibration – 20” Bi Directional Prover/1300Cum/h capacity SVP/Master meters.

• Master Meters – 3 Helical bladed turbine meters used: • Single meter mode. • Two meter mode • Three meter mode

• Flow Rate – 2-3000 Cum/h.

• Viscosity Range – 1.5-200cS (API 25-45).

• Reynolds Number Range – 300 – 1,200,000.

• Uncertainty range: 0.015%-0.05% depending on base calibration method.

• Temperature stability – 0.2 Deg. C.

Commissioning

• The facility has to be checked in all its modes: • Over the full viscosity range.

• Against the prover

• Against a single master meter ( all three meters)

• Multiple Master meters.

• Repeatability with Prover

• Repeatability with master meters

Calibration of the Master meters

Calibration of the MUT (USM)

Valves (Bloody valves!!!)

• One of the biggest issues during the commissioning was valve leakage: • New Double Block and Bleed Valves leaking.

• Valve damage by swarf.

• 4 Way Prover valve not set up correctly

Leaking MUT Valve

Original calibration curve

Leaking 4 way valve calibration curve

Leaking 4 Way Prover Valves

Software (Bloody Software!!)

The original software initial tests showed good agreement with the prover tests – then some software changes and the calibration changed. It turned out to be MF calculation used flowrate before corrected for MM Reynolds number.

Master Meter Tests after Software Correction

Conclusions

• There is a need to calibrate meters with linearity issues with Reynolds number over as close a range to that in operation

• CEESI have built a multi-viscosity to try to achieve this goal for many oil applications.

• A GE 10” USM was used as a commissioning tool to help setup the flow laboratory. • The wide range and low pressure drop made it a good choice for commissioning. • It worked efficiently as a check meter • It showed clearly when the system had leaks • It allowed us to check the full prover and master meter performance. • It allowed us to confirm the master meter operation, particularly for improved

repeatability when calibrating less repeatable meters.