ISO/TS 21354:2020

Measurement of multiphase fluid flow

This document establishes a common basis for, and assistance in, the classification of applications and multiphase meters, as well as guidance and recommendations for the implementation and use of such meters. The so-called in-line multiphase flow meters (MPFMs) that directly measure the oil, water and gas flow rates, as well as the partial- and full-separation MPFMs are the main focus of this document. Conventional two- or three-phase separators are not included in this document. Only limited reference is made to wet-gas meters, since although wet-gas flow is a subset of multiphase flow, wet-gas measurement is covered by ISO/TR 11583 and ISO/TR 12748.

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General Information

• Status: Published
• Publication Date: 26-Nov-2020
• ICS: 75.180.30 - Volumetric equipment and measurements
• Technical Committee: ISO/TC 28/SC 2 - Measurement of petroleum and related products
• Drafting Committee: ISO/TC 28/SC 2 - Measurement of petroleum and related products
• Current Stage: 6060 - International Standard published
• Start Date: 27-Nov-2020
• Due Date: 28-Jan-2020
• Completion Date: 27-Nov-2020

Standards Content (Sample)

TECHNICAL ISO/TS
SPECIFICATION 21354
First edition
2020-11
Measurement of multiphase fluid flow
Reference number
ISO/TS 21354:2020(E)
ISO 2020
---------------------- Page: 1 ----------------------
ISO/TS 21354:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TS 21354:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................vi

Introduction ..............................................................................................................................................................................................................................vii

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

3.1 Terms related to multiphase flow metering .................................................................................................................. 1

3.2 Terms related to metrology.......................................................................................................................................................... 7

4 Symbols and subscripts ..............................................................................................................................................................................10

4.1 Symbols ......................................................................................................................................................................................................10

4.2 Colours and symbols used in schematic drawings ...............................................................................................10

5 Multiphase flow ..................................................................................................................................................................................................11

5.1 General ........................................................................................................................................................................................................11

5.2 Multiphase flow regime maps .................................................................................................................................................12

5.2.1 General...................................................................................................................................................................................12

5.2.2 Vertical flows ....................................................................................................................................................................12

5.2.3 Horizontal flows ............................................................................................................................................................13

5.3 Slip effects ................................................................................................................................................................................................14

5.4 Classification of multiphase flows .......................................................................................................................................15

6 Aims of multiphase flow measurement .....................................................................................................................................16

6.1 General ........................................................................................................................................................................................................16

6.2 Individual-well surveillance or monitoring ................................................................................................................18

6.2.1 General...................................................................................................................................................................................18

6.2.2 Production optimization ........................................................................................................................................19

6.2.3 Flow assurance ...............................................................................................................................................................19

6.3 Well testing ..............................................................................................................................................................................................19

6.3.1 General...................................................................................................................................................................................19

6.3.2 Conventional well testing ......................................................................................................................................20

6.3.3 Well testing by MPFMs.............................................................................................................................................21

6.4 Production allocation metering .............................................................................................................................................23

6.5 Fiscal or custody transfer measurement .......................................................................................................................26

6.6 Summary of advantages and disadvantages of MPFMs ....................................................................................26

7 Production envelope and installation design guidelines ........................................................................................26

7.1 General ........................................................................................................................................................................................................26

7.2 Production envelope .......................................................................................................................................................................27

7.2.1 Plotting the production envelope in the two-phase flow map ..............................................27

7.2.2 Plotting the production envelope in the composition map......................................................28

7.3 MPFM measuring envelope .......................................................................................................................................................29

7.3.1 Plotting the MPFM measuring envelope in the two-phase flow map ..............................29

7.3.2 Plotting the MPFM measuring envelope in the composition map .....................................30

7.4 Using the flow maps during testing ...................................................................................................................................31

7.5 Cumulative performance plot .................................................................................................................................................33

7.6 Other considerations ......................................................................................................................................................................34

8 Performance specification ......................................................................................................................................................................37

8.1 General ........................................................................................................................................................................................................37

8.2 Technical description .....................................................................................................................................................................38

8.3 Specification of individual sensors and primary devices ................................................................................38

8.4 Specification of output data and formats ......................................................................................................................38

8.5 Measuring range, rated operating conditions and limiting conditions ...............................................39

8.6 Measurement uncertainty ..........................................................................................................................................................39

8.6.1 General...................................................................................................................................................................................39

8.6.2 Measurement uncertainty evaluation of MPFMs ..............................................................................40

© ISO 2020 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/TS 21354:2020(E)

8.6.3 Influence quantities and sensitivity coefficients ...............................................................................40

8.6.4 Repeatability ....................................................................................................................................................................41

8.6.5 Stability and frequency response ...................................................................................................................41

8.7 Guideline on MPFM performance specification ......................................................................................................41

8.7.1 General...................................................................................................................................................................................41

8.7.2 Technical descriptions .............................................................................................................................................42

8.7.3 Specification of input data ....................................................................................................................................42

8.7.4 Specification of output data ................................................................................................................................42

8.7.5 Rated operating conditions and limiting conditions .....................................................................43

8.7.6 Measurement uncertainty ....................................................................................................................................44

8.7.7 Two-phase flow map .................................................................................................................................................46

8.7.8 Composition map .........................................................................................................................................................46

9 Testing, calibration and adjustment .............................................................................................................................................46

9.1 General ........................................................................................................................................................................................................46

9.2 Factory acceptance testing (FAT) .........................................................................................................................................47

9.3 Calibration and test of MPFMs ...............................................................................................................................................48

9.3.1 General...................................................................................................................................................................................48

9.3.2 Performance verification in static conditions .................. ....................................................................48

9.3.3 Performance verification in dynamic conditions ..............................................................................49

9.3.4 Factory test ........................................................................................................................................................................51

9.3.5 Test facility .........................................................................................................................................................................51

9.3.6 In situ test...........................................................................................................................................................................53

9.3.7 Further information on performance testing ......................................................................................55

9.3.8 Test report ..........................................................................................................................................................................58

9.4 Adjustment of MPFMs ....................................................................................................................................................................60

9.4.1 General...................................................................................................................................................................................60

9.4.2 Adjustment based on static configuration ..............................................................................................60

9.4.3 Adjustment based on performance verification in dynamic conditions .......................60

9.5 Blind tests .................................................................................................................................................................................................61

9.5.1 Scope and objective of MPFM blind test ...................................................................................................61

9.5.2 Organization and implementation ................................................................................................................61

9.5.3 Multiphase flow loop .................................................................................................................................................61

9.5.4 Test matrix .........................................................................................................................................................................62

9.5.5 Information to be provided by MPFM vendors ..................................................................................63

9.5.6 Information provided to MPFM vendors .................................................................................................63

9.5.7 Test completion ...................................................................... ........................................................................................63

9.5.8 Test results and deliverables ..............................................................................................................................64

10 Field installation and commissioning .........................................................................................................................................64

10.1 General ........................................................................................................................................................................................................64

10.2 Installation considerations ........................................................................................................................................................64

10.3 Installation and site integration ............................................................................................................................................65

10.3.1 General...................................................................................................................................................................................65

10.3.2 Installation requirements .....................................................................................................................................66

10.3.3 Electrical connections and power requirements ..............................................................................66

10.3.4 Function test .....................................................................................................................................................................66

10.3.5 Fluid calculation checks ..........................................................................................................................................66

10.4 Commissioning ....................................................................................................................................................................................66

10.4.1 General...................................................................................................................................................................................66

10.4.2 Preparation ........................................................................................................................................................................67

10.4.3 Documentation and equipment .......................................................................................................................67

10.4.4 On site authorization .................................................................................................................................................67

10.4.5 Commissioning activities .......................................................................................................................................67

10.5 Start-up .......................................................................................................................................................................................................68

11 V erification during operation ..............................................................................................................................................................68

11.1 General ........................................................................................................................................................................................................68

11.2 Baseline monitoring ........................................................................................................................................................................69

11.3 Self-checking, self-diagnostic capabilities and internal redundancy ....................................................70

iv © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TS 21354:2020(E)

11.4 Comparison with model-based multiphase flow calculations ....................................................................70

11.5 Two meters in series .......................................................................................................................................................................70

11.6 Mobile test units .................................................................................................................................................................................71

11.7 Tracer technology ..............................................................................................................................................................................71

11.8 Injection .....................................................................................................................................................................................................72

11.9 Sampling ....................................................................................................................................................................................................72

11.9.1 General...................................................................................................................................................................................72

11.9.2 Sampling for information about WLR ........................................................................................................72

11.10 Imbalances and reconciliation factor ...............................................................................................................................72

11.11 Geo-chemical fingerprinting ....................................................................................................................................................74

11.12 Subsea systems verification ......................................................................................................................................................74

Annex A (informative) Multiphase meter technologies .................................................................................................................75

Annex B (informative) Fluid properties and hydrocarbon behaviour ...........................................................................87

Annex C (informative) Example of field test reference measurements .........................................................................92

Bibliography .............................................................................................................................................................................................................................96

© ISO 2020 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO/TS 21354:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 28, Petroleum and related products, fuels

and lubricants from natural or synthetic sources, Subcommittee SC 2, Measurement of petroleum and

related products.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
vi © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/TS 21354:2020(E)
Introduction

The need for multiphase flow measurement in the oil and gas production industry has been evident for

many years. Multiphase meters have been developed since the early eighties by research organizations,

meter manufacturers, oil and gas production companies and others: different technologies and various

combinations of technologies have been employed. Some technologies have been abandoned, whereas

other meters have become commercially available: the number of applications and users is increasing.

The first Norwegian Society for Oil and Gas Measurement (NFOGM) handbook of multiphase metering

(hereafter simply called the Handbook) was published in 1995 (see Reference [16]). Since then,

multiphase flow measurement has matured. New applications of multiphase flow meters (MPFMs)

have emerged, from simply being a replacement for the conventional test separator shared by a number

of wells, towards more compact and low-cost meters with application on a one-per-well basis and

installations on shore, topside and subsea.

Since multiphase flow metering technologies and applications had developed significantly since 1995,

NFOGM updated the Handbook in 2003-5 to reflect these improvements and to make it the main

guide for state-of-the-art multiphase flow measurement. That work was financed by NFOGM and The

Norwegian Society of Chartered Technical and Scientific Professionals (Tekna).

Following calls from industry to produce an ISO document, NFOGM very generously allowed ISO to use

the Handbook as the basis for this document.

This document is intended to serve as guidance for users, designers and manufacturers of multiphase

metering systems.

The document can also serve as an introduction to newcomers in the field of multiphase flow

measurement, with definition of terms and a description of multiphase flow in closed conduits being

included.

Even if the individual flow rates of each constituent are of primary interest, often their ratios (e.g. water

liquid ratio, gas oil ratio) are useful as operational parameters. Total hydrocarbon mass flow rate can

be required in particular applications. Constituents other than oil, gas and water flow rates or ratios of

these are not dealt with in this document.

The performance of a multiphase flow meter in terms of uncertainty, repeatability and range is of great

importance, as this enables the user to compare different meters and evaluate their suitability for use

in specific applications. Clause 8 covers this issue in detail and proposes standard methods to describe

performance.

Testing and qualification of MPFMs are required to verify performance. Guidance is provided to help

optimize the outcome of such activities. Since MPFMs measure at line conditions, the primary output is

individual flow rates and fractions at actual conditions (i.e. at the operating pressure and temperature).

Conversion of these actual flow rates to flow rates at standard conditions requires knowledge of

composition and mass transfer between the liquid and the gas phases, which can require sampling.

The clauses logically proceed from an introduction to multiphase flow measurement, via selection

of technology, design considerations and performance specifications, to field installation and

commissioning, and finally the operation of MPFMs.

The definitions in Clause 3 have been extended and split into definitions relating to multiphase flows in

a closed conduit (see 3.1) and definitions relating to metrology that can be useful in characterizing the

performance of a multiphase flow meter.

Clause 5 provides a general introduction to multiphase flows. This clause includes extended descriptions

of flow regimes and slip effects in multiphase flows.

Clause 6 covers the aims of multiphase flow measurement, giving the reasoning for selection,

installation and operation of multiphase flow metering systems in various applications.

© ISO 2020 – All rights reserved vii
---------------------- Page: 7 ----------------------
ISO/TS 21354:2020(E)

Clause 7 presents guidelines for designing MPFM installations using the two-phase flow map and the

composition map.

Standardized performance specification of MPFMs is essential, both for comparison of measuring

ranges and measurement uncertainties, but also for more efficient selection of technology (Clause 8).

Claus
...

TECHNICAL ISO/TS
SPECIFICATION 21354
First edition
Measurement of multiphase fluid flow
Mesurage des écoulements de fluides polyphasiques
PROOF/ÉPREUVE
Reference number
ISO/TS 21354:2020(E)
ISO 2020
---------------------- Page: 1 ----------------------
ISO/TS 21354:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/TS 21354:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................vi

Introduction ..............................................................................................................................................................................................................................vii

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

3.1 Terms related to multiphase flow metering .................................................................................................................. 1

3.2 Terms related to metrology.......................................................................................................................................................... 7

4 Symbols and subscripts ................................................................................................................................................................................. 9

4.1 Symbols ......................................................................................................................................................................................................... 9

4.2 Colours and symbols used in schematic drawings ...............................................................................................10

5 Multiphase flow ..................................................................................................................................................................................................11

5.1 General ........................................................................................................................................................................................................11

5.2 Multiphase flow regime maps .................................................................................................................................................11

5.2.1 General...................................................................................................................................................................................11

5.2.2 Vertical flows ....................................................................................................................................................................12

5.2.3 Horizontal flows ............................................................................................................................................................13

5.3 Slip effects ................................................................................................................................................................................................14

5.4 Classification of multiphase flows .......................................................................................................................................15

6 Aims of multiphase flow measurement .....................................................................................................................................16

6.1 General ........................................................................................................................................................................................................16

6.2 Individual-well surveillance or monitoring ................................................................................................................18

6.2.1 General...................................................................................................................................................................................18

6.2.2 Production optimization ........................................................................................................................................19

6.2.3 Flow assurance ...............................................................................................................................................................19

6.3 Well testing ..............................................................................................................................................................................................19

6.3.1 General...................................................................................................................................................................................19

6.3.2 Conventional well testing ......................................................................................................................................20

6.3.3 Well testing by MPFMs.............................................................................................................................................21

6.4 Production allocation metering .............................................................................................................................................23

6.5 Fiscal or custody transfer measurement .......................................................................................................................26

6.6 Summary of advantages and disadvantages of MPFMs ....................................................................................26

7 Production envelope and installation design guidelines ........................................................................................26

7.1 General ........................................................................................................................................................................................................26

7.2 Production envelope .......................................................................................................................................................................27

7.2.1 Plotting the production envelope in the two-phase flow map ..............................................27

7.2.2 Plotting the production envelope in the composition map......................................................28

7.3 MPFM measuring envelope .......................................................................................................................................................29

7.3.1 Plotting the MPFM measuring envelope in the two-phase flow map ..............................29

7.3.2 Plotting the MPFM measuring envelope in the composition map .....................................30

7.4 Using the flow maps during testing ...................................................................................................................................31

7.5 Cumulative performance plot .................................................................................................................................................33

7.6 Other considerations ......................................................................................................................................................................34

8 Performance specification ......................................................................................................................................................................37

8.1 General ........................................................................................................................................................................................................37

8.2 Technical description .....................................................................................................................................................................38

8.3 Specification of individual sensors and primary devices ................................................................................38

8.4 Specification of output data and formats ......................................................................................................................38

8.5 Measuring range, rated operating conditions and limiting conditions ...............................................39

8.6 Measurement uncertainty ..........................................................................................................................................................39

8.6.1 General...................................................................................................................................................................................39

8.6.2 Measurement uncertainty evaluation of MPFMs ..............................................................................40

© ISO 2020 – All rights reserved PROOF/ÉPREUVE iii
---------------------- Page: 3 ----------------------
ISO/TS 21354:2020(E)

8.6.3 Influence quantities and sensitivity coefficients ...............................................................................40

8.6.4 Repeatability ....................................................................................................................................................................41

8.6.5 Stability and frequency response ...................................................................................................................41

8.7 Guideline on MPFM performance specification ......................................................................................................41

8.7.1 General...................................................................................................................................................................................41

8.7.2 Technical descriptions .............................................................................................................................................42

8.7.3 Specification of input data ....................................................................................................................................42

8.7.4 Specification of output data ................................................................................................................................42

8.7.5 Rated operating conditions and limiting conditions .....................................................................43

8.7.6 Measurement uncertainty ....................................................................................................................................44

8.7.7 Two-phase flow map .................................................................................................................................................46

8.7.8 Composition map .........................................................................................................................................................46

9 Testing, calibration and adjustment .............................................................................................................................................46

9.1 General ........................................................................................................................................................................................................46

9.2 Factory acceptance testing (FAT) .........................................................................................................................................47

9.3 Calibration and test of MPFMs ...............................................................................................................................................48

9.3.1 General...................................................................................................................................................................................48

9.3.2 Performance verification in static conditions .................. ....................................................................48

9.3.3 Performance verification in dynamic conditions ..............................................................................49

9.3.4 Factory test ........................................................................................................................................................................51

9.3.5 Test facility .........................................................................................................................................................................51

9.3.6 In situ test...........................................................................................................................................................................53

9.3.7 Further information on performance testing ......................................................................................55

9.3.8 Test report ..........................................................................................................................................................................58

9.4 Adjustment of MPFMs ....................................................................................................................................................................60

9.4.1 General...................................................................................................................................................................................60

9.4.2 Adjustment based on static configuration ..............................................................................................60

9.4.3 Adjustment based on performance verification in dynamic conditions .......................60

9.5 Blind tests .................................................................................................................................................................................................61

9.5.1 Scope and objective of MPFM blind test ...................................................................................................61

9.5.2 Organization and implementation ................................................................................................................61

9.5.3 Multiphase flow loop .................................................................................................................................................61

9.5.4 Test matrix .........................................................................................................................................................................62

9.5.5 Information to be provided by MPFM vendors ..................................................................................63

9.5.6 Information provided to MPFM vendors .................................................................................................63

9.5.7 Test completion ...................................................................... ........................................................................................63

9.5.8 Test results and deliverables ..............................................................................................................................64

10 Field installation and commissioning .........................................................................................................................................64

10.1 General ........................................................................................................................................................................................................64

10.2 Installation considerations ........................................................................................................................................................64

10.3 Installation and site integration ............................................................................................................................................65

10.3.1 General...................................................................................................................................................................................65

10.3.2 Installation requirements .....................................................................................................................................66

10.3.3 Electrical connections and power requirements ..............................................................................66

10.3.4 Function test .....................................................................................................................................................................66

10.3.5 Fluid calculation checks ..........................................................................................................................................66

10.4 Commissioning ....................................................................................................................................................................................66

10.4.1 General...................................................................................................................................................................................66

10.4.2 Preparation ........................................................................................................................................................................67

10.4.3 Documentation and equipment .......................................................................................................................67

10.4.4 On site authorization .................................................................................................................................................67

10.4.5 Commissioning activities .......................................................................................................................................67

10.5 Start-up .......................................................................................................................................................................................................68

11 V erification during operation ..............................................................................................................................................................68

11.1 General ........................................................................................................................................................................................................68

11.2 Baseline monitoring ........................................................................................................................................................................69

11.3 Self-checking / self-diagnostic capabilities / internal redundancy........................................................70

iv PROOF/ÉPREUVE © ISO 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/TS 21354:2020(E)

11.4 Comparison with model-based multiphase flow calculations ....................................................................70

11.5 Two meters in series .......................................................................................................................................................................70

11.6 Mobile test units .................................................................................................................................................................................71

11.7 Tracer technology ..............................................................................................................................................................................71

11.8 Injection .....................................................................................................................................................................................................72

11.9 Sampling ....................................................................................................................................................................................................72

11.9.1 General...................................................................................................................................................................................72

11.9.2 Sampling for information about WLR ........................................................................................................72

11.10 Imbalances and reconciliation factor ...............................................................................................................................72

11.11 Geo-chemical fingerprinting ....................................................................................................................................................74

11.12 Subsea systems verification ......................................................................................................................................................74

Annex A (informative) Multiphase meter technologies .................................................................................................................75

Annex B (informative) Fluid properties and hydrocarbon behaviour ...........................................................................87

Annex C (informative) Example of field test reference measurements .........................................................................92

Bibliography .............................................................................................................................................................................................................................96

© ISO 2020 – All rights reserved PROOF/ÉPREUVE v
---------------------- Page: 5 ----------------------
ISO/TS 21354:2020(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 28, Petroleum and related products, fuels

and lubricants from natural or synthetic sources, Subcommittee SC 2, Measurement of petroleum and

related products.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
vi PROOF/ÉPREUVE © ISO 2020 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/TS 21354:2020(E)
Introduction

The need for multiphase flow measurement in the oil and gas production industry has been evident for

many years. Multiphase meters have been developed since the early eighties by research organizations,

meter manufacturers, oil and gas production companies and others: different technologies and various

combinations of technologies have been employed. Some technologies have been abandoned, whereas

other meters have become commercially available: the number of applications and users is increasing.

The first Norwegian Society for Oil and Gas Measurement (NFOGM) handbook of multiphase metering

(hereafter simply called the Handbook) was published in 1995 (see Reference [9]). Since then,

multiphase flow measurement has matured. New applications of multiphase flow meters (MPFMs)

have emerged, from simply being a replacement for the conventional test separator shared by a number

of wells, towards more compact and low-cost meters with application on a one-per-well basis and

installations on shore, topside and subsea.

Since multiphase flow metering technologies and applications had developed significantly since 1995,

NFOGM updated the Handbook in 2003-5 to reflect these improvements and to make it the main

guide for state-of-the-art multiphase flow measurement. That work was financed by NFOGM and The

Norwegian Society of Chartered Technical and Scientific Professionals (Tekna).

Following calls from industry to produce an ISO document, NFOGM very generously allowed ISO to use

the Handbook as the basis for this document.

This document is intended to serve as guidance for users, designers and manufacturers of multiphase

metering systems.

The document can also serve as an introduction to newcomers in the field of multiphase flow

measurement, with definition of terms and a description of multiphase flow in closed conduits being

included.

Even if the individual flow rates of each constituent are of primary interest, often their ratios (e.g. water

liquid ratio, gas oil ratio) are useful as operational parameters. Total hydrocarbon mass flow rate can

be required in particular applications. Constituents other than oil, gas and water flow rates or ratios of

these are not dealt with in this document.

The performance of a multiphase flow meter in terms of uncertainty, repeatability and range is of great

importance, as this enables the user to compare different meters and evaluate their suitability for use

in specific applications. Clause 8 covers this issue in detail and proposes standard methods to describe

performance.

Testing and qualification of MPFMs are required to verify performance. Guidance is provided to help

optimize the outcome of such activities. Since MPFMs measure at line conditions, the primary output is

individual flow rates and fractions at actual conditions (e.g. at the operating pressure and temperature).

Conversion of these actual flow rates to flow rates at standard conditions requires knowledge of

composition and mass transfer between the liquid and the gas phases, which can require sampling.

The clauses logically proceed from an introduction to multiphase flow measurement, via selection

of technology, design considerations and performance specifications, to field installation and

commissioning, and finally the operation of MPFMs.

The definitions in Clause 3 have been extended and split into definitions relating to multiphase flows in

a closed conduit (see 3.1) and definitions relating to metrology that can be useful in characterizing the

performance of a multiphase flow meter.

Clause 5 provides a general introduction to multiphase flows. This clause includes extended descriptions

of flow regimes and slip effects in multiphase flows.

Clause 6 covers the aims of multiphase flow measurement, giving the reasoning for selection,

installation and operation of multiphase flow metering systems in various applications.

© ISO 2020 – All rights reserved PROOF/ÉPREUVE vii
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ISO/TS 21354:2020(E)

Clause 7 presents guidelines for designing MPFM installations using the two-phase flow map and the

composition map.
Standardized performance specification of MPFMs is essential,
...