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PETRONAS TECHNICAL STANDARDS

DESIGN AND ENGINEERING PRACTICE

MANUAL

LIQUID HYDROCARBON CUSTODY TRANSFER ANDALLOCATION MEASUREMENT

PTS 32.32.00.43JANUARY 2010

2010 PETROLIAM NASIONAL BERHAD (PETRONAS)All rights reserved. No part of this document may be reproduced, stored in a retrieval system or transmitted in any form or by any means (electronic,

mechanical, photocopying, recording or otherwise) without the permission of the copyright owner

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This New PTS 32.32.00.43 - Liquid Hydrocarbon Custody Transfer and Allocation Measurementhas been developed incorporating:

1. PETRONAS Lessons Learnt2. Best Practice3. New information issued by relevant industry code and standards.

4. Replacement of Current PTS 20.221 (deleted).

All updates in the document are highlighted in Summary of Changes.

Document ApprovalName Designation Date Signature

Initiator Aneeta Kajah Ahmad Instrument Engineer

Reviewed Razali Ibrahim Principal Engineer& COP Measurement

Approved V.R. Harindran Custodian Engineer(Technical Authority),Instrument & Control,PA&O - GTS

Verified Saifol Mualim B AhmadYahaya

Senior Manager,Engineering - GTS

Verified Pau Kiew Huai General Manager,Engineering - GTS

Endorsed Pramod KumarKarunakaran

Senior GeneralManager, GTS

Revision HistoryDate Version Descript ion of Updates Author

PTS Circular2009-SKG14/PTS-012

PTS No: 32.32.00.43

Publication Title: Liquid Hydrocarbon Custody Transfer andAllocation Measurement

Base PTS Version: Revision 13

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PREFACE

PETRONAS Technical Standards (PTS) publications reflect the views, at the time of publication ofPETRONAS OPUs/Divisions.

They are based on the experience acquired during the involvement with the design, construction,operation and maintenance of processing units and facilities. Where appropriate they are based on,or reference is made to, national and international standards and codes of practice.

The objective is to set the recommended standard for good technical practice to be applied byPETRONAS' OPUs in oil and gas production facilities, refineries, gas processing plants, chemicalplants, marketing facilities or any other such facility, and thereby to achieve maximum technical andeconomic benefit from standardisation.

The information set forth in these publications is provided to users for their consideration anddecision to implement. This is of particular importance where PTS may not cover every requirementor diversity of condition at each locality. The system of PTS is expected to be sufficiently flexible toallow individual operating units to adapt the information set forth in PTS to their own environment andrequirements.

When Contractors or Manufacturers/Suppliers use PTS they shall be solely responsible for the qualityof work and the attainment of the required design and engineering standards. In particular, for thoserequirements not specifically covered, it is expected of them to follow those design and engineeringpractices which will achieve the same level of integrity as reflected in the PTS. If in doubt, theContractor or Manufacturer/Supplier shall, without detracting from his own responsibility, consult theowner.

The right to use PTS rests with three categories of users:

1) PETRONAS and its affiliates.2) Other parties who are authorised to use PTS subject to appropriate contractualarrangements.

3) Contractors/subcontractors and Manufacturers/Suppliers under a contract with users referredto under 1) and 2) which requires that tenders for projects, materials supplied or - generally - workperformed on behalf of the said users comply with the relevant standards.

Subject to any particular terms and conditions as may be set forth in specific agreements with users,PETRONAS disclaims any liability of whatsoever nature for any damage (including injury or death)suffered by any company or person whomsoever as a result of or in connection with the use,application or implementation of any PTS, combination of PTS or any part thereof. The benefit of thisdisclaimer shall inure in all respects to PETRONAS and/or any company affiliated to PETRONAS thatmay issue PTS or require the use of PTS.

Without prejudice to any specific terms in respect of confidentiality under relevant contractualarrangements, PTS shall not, without the prior written consent of PETRONAS, be disclosed by users

to any company or person whomsoever and the PTS shall be used exclusively for the purpose theyhave been provided to the user. They shall be returned after use, including any copies which shallonly be made by users with the express prior written consent of PETRONAS.

The copyright of PTS vests in PETRONAS. Users shall arrange for PTS to be held in safe custodyand PETRONAS may at any time require information satisfactory to PETRONAS in order to ascertainhow users implement this requirement.

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TABLE OF CONTENTS

1. INTRODUCTION ....................................................................................................................11.1 SCOPE.....................................................................................................................11.2 DISTRIBUTION, INTENDED USE AND REGULATORY ........................................11.3 DEFINITIONS...........................................................................................................11.4 ABBREVIATIONS ....................................................................................................41.5 CROSS-REFERENCES...........................................................................................51.6 ORDER OF PROCEDURES....................................................................................5

2. GENERAL REQUIREMENT................................................................................................62.1 UNIT OF MEASUREMENT......................................................................................62.2 APPROVAL REQUIREMENT..................................................................................62.3 DOCUMENTATION .................................................................................................8

3. DESIGN OF METERING SYSTEM.....................................................................................93.1 GENERAL REQUIREMENT ....................................................................................93.2 METER RUN DESIGN AND PIPE WORK METERING SKID ...............................103.3 FLOWMETER TYPE..............................................................................................113.4 METER PROVING SYSTEM DESIGN ..................................................................123.5 METERING SKID AND CONTROL ROOM INSTRUMENTATION .......................163.6 METERING COMPUTERS AND CONTROL SYSTEM REQUIREMENTS...........183.7 SAMPLING AND ANALYSIS REQUIREMENT......................................................213.8 METERING DATA AND REPORTING ..................................................................22

4. TESTING, CALIBRATION AND COMMISSIONING.........................................................234.1 GENERAL REQUIREMENT ..................................................................................234.2 CALIBRATION .......................................................................................................234.3 TESTING................................................................................................................254.4 COMMISSIONING.................................................................................................29

5. OPERATION, VALIDATION AND ACCOUNTING............................................................315.1 GENERAL REQUIREMENT ..................................................................................315.2 SYSTEM OPERATION ..........................................................................................315.3 SYSTEM VALIDATION..........................................................................................325.4 SYSTEM MAINTENANCE.....................................................................................345.5 SECURITY.............................................................................................................345.6 ACCOUNTING/ALLOCATION MANUAL...............................................................355.7 METERING STATION RECORD KEEPING..........................................................355.8 SYSTEM REPORTING..........................................................................................36

6. REFERENCES..................................................................................................................37APPENDIX 1 LIQUID HYDROCARBON METERING SYSTEM TYPICAL SCHEMATIC

DIAGRAM...............................................................................................................1APPENDIX 2

TYPICAL FLOW CHART APPLICATION FOR ACCEPTANCE OFCUSTODY TRANSFER METERING SYSTEM (IN MALAYSIA) ...........................1

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1. INTRODUCTION

1.1 SCOPE

This PTS (guidelines) specifies the minimum requirements in the design, installation,testing, commissioning, operation and maintenance of Liquid Hydrocarbon Custody

Transfer and Allocation Metering System, for installations in Malaysia or in any othercountries. It is intended for use by the Principal and Contractor when preparing aspecification for equipment packages and also during the operation and maintenance of thesystem.

For specifications on metering system using turbine meters, please also refer to PTS32.32.00.11 and also Requisition Sheet PTS 32.32.00.93.

1.2 DISTRIBUTION, INTENDED USE AND REGULATORY

Unless otherwise authorised by PETRONAS, the distribution of this PTS is confined tocompanies forming part of PETROANS or managed by a Group company, and to

Contractors and Manufacturers nominated by them.

It is intended for use in oil refineries, chemical plants, gas plants and, where applicable, inonshore and offshore exploration and production facilities and supply/marketinginstallations.

If national and/or local regulations exist in which some of the requirements may be morestringent than in this PTS the Contractor shall determine by careful scrutiny which of therequirements are the more stringent and which combination of requirements will beacceptable as regards safety, environmental, economic and legal aspects. In all cases theContractor shall inform the Principal of any deviation from the requirements of this PTSwhich is considered to be necessary in order to comply with national and/or localregulations. The Principal may then negotiate with the Authorities concerned with the

object of obtaining agreement to follow this PTS as closely as possible.

1.3 DEFINITIONS

1.3.1 General definitions

The Contractor is the party that carries out all or part of the design, engineering,procurement, construction, commissioning or management of a project or operation of afacility. The Principal may undertake all or part of the duties of the Contractor.

The Manufacturer/Supplier is the party that manufactures or supplies equipment andservices to perform the duties specified by the Contractor.

The Principal is the party that initiates the project and ultimately pays for its design andconstruction. The Principal will generally specify the technical requirements. The Principalmay also include an agent or consultant authorised to act for, and on behalf of, thePrincipal.

The word shallis a requirement.

The word shouldis a recommendation.

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1.3.2 Specific definitions

AccuracyThe measure of the closeness of a measurement to the true value.

Al locat ion Metering System (for liquid hydrocarbon)

A measuring system comprising mechanical, instrument and computer parts whoseregistered measured quantity is used for allocation between two or more Contractors whichinvolved in sharing the same facilities for their operation. This system normally has anuncertainty of +/- 1%.

Automatic SamplerA system which when installed in a pipe and actuated by automatic control equipment,enables a representative sample to be obtained from the liquid flowing in the pipe. Thesystem generally consists of a sampling probe, a sample extractor, an associated controllerand a sample receiver. Normally it is also equipped with a sampler performance monitoringdevice.

Computer Part

The part of the metering system that consists of digital computers and receives digitalsignals from A/D converters or from digital instrument loops.

Control ChartA graphical chart of the constancy measurement used for evaluating whether meter provingoperations are in or out of statistical control. On it are shown the +/- 3 sigma limits ofdispersion from the average system factor, x (standard deviation), within which themeasurement system considered to be in control (API Chapter 13).

Custody Transfer Metering System (for liquid hydrocarbon)A measuring system comprising mechanical, instrument and computer parts whoseregistered measured quantity is used for sale where there is a change in ownership. Thissystem normally, has an uncertainty of +/- 0.25% of standard volume.

DensityThe density of a quantity of a homogeneous substance is the ration of its mass of itsvolume. The density varies as the temperature changes and is therefore generallyexpressed as the mass per unit of volume at a specific temperature.

Displacement ProverProver which operate on the principle of the repeatable displacement of known volume ofliquid from a calibrated section of pipe between two detectors. These include prover thatwas commonly referred to as either conventional pipe prover or small volume prover.

Flow computerIt is an arithmetic processing unit and associated memory device that accepts electrically

converted signals representing input variables from a liquid measurement system andperforms calculations for the purpose of providing flow rate and total quantity data.

Flow meterFlow measuring device which, indicates the measured flow rate. In some cases, it is also adevice that indicates the total amount of fluid passes during a selected time interval.

Instrument LoopIncludes all elements that form part of the measurement of each individual quantity fromsensor to input of the A/D converter or input of digital signal to the computer part.

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LinearityThe deviation or spread of calibration data points from an acceptable straight line over thedefined flow range.

Linearity of a MeterThe ideal accuracy curve of a volume meter is a straight line denoting a constant meter

factor. Meter linearity is expressed as the total range of deviation of the accuracy.

Maximum Meter Flow RateThe maximum rate of flow recommended by the meter manufacturer or authorised by aregulatory body. The maximum rate is determined by considerations of accuracy, durability,pressure drop, repeatability and linearity.

Meter ProvingAn exercise carried out in accordance to the proving procedure in order to determine therelationship between the volume of liquid passing through a meter at one set of conditionsand the indicated or reference volume at the same conditions.

Meter Run

A flow measuring device complete with associated strainers, entry/exit pipework, upstreamand downstream straight lengths, flow meter and flow straighteners.

Minimum Meter Flow RateThe minimum rate of flow recommended by the meter manufacturer or authorized by aregulatory body. The minimum rate is determined by considerations of accuracy,repeatability and linearity.

Online Density MeterA density meter also known as densitometer operating on a representative sample of theprocess material withdrawn continuously from the process line or vessel via a samplingsystem.

Positive Displacement MeterA meter in which the measuring element is the discrete volumetric segments in the meterand volume is directly measured by continuous separating (isolating) a flow stream intodiscrete volume segments and counting them.

Prover ComputerIt is an arithmetic processing unit and associated memory device which consists only theproving function for the proving of meters and calculation of meter factors.

Pulse InterpolationAny of the various techniques by which the whole number of meter pulses is countedbetween two events (such as detector switch closures) and any remaining fraction of apulse between the two events is calculated.

RepeatabilityThe quality which characterize the ability of a measuring instrument to give identicalindications or responses, for repeated applications of the same value of the measuredquantity under stated conditions of use.

SamplingAn exercise in accordance to the procedure that is carried out either automatically ormanually to obtain a sample that is representative of the contents of any pipe, tank or othervessel and to replace that sample in a container from which a representative test specimenbe taken for analysis.

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Small Volume ProverAny pipe prover used to calibrate a meter, having a volume between detectors that doesnot permit a minimum accumulation of 10,000 whole (unaltered) pulses from the meter.Small volume provers require meter pulses discrimination by pulse interpolation or othertechnique to increase the resolution.

Standard Reference ConditionsThe conditions of temperature and pressure to which measured volumes are to becorrected. Standard reference conditions for pressure and temperature shall be 101.325kPa (abs) and 15

0C respectively, in accordance with ISO 5024.

Station ComputerIt is an arithmetic processing unit and associated memory device which sends commandsand accepts calculated data from Flow Computer and Prover Computer for StationTotalisation computation and archiving.

Turbine MeterA meter in which the measuring element is a multi bladed rotor or impeller to which themetered stream imparts a rotational velocity that is proportional to the mean velocity of the

stream. Measured volume is registered by counting rotor revolutions.

UncertaintyThe part of the expression of the result of a measurement which states the range of valueswithin which the true value of, if appropriate, the conventional true value is estimated to fallwithin stated confidence level as defined in ISO 5168.

For the purpose of this PTS, all uncertainty quoted, are stated at 95% confidence level.

ValidationThe process of confirming or substantiating the accuracy of input variables to ameasurement system at normal operating conditions, using reference equipment traceableto certified standards.

1.4 ABBREVIATIONS

AC - Alternating Current

A/D - Analogue to Digital

AGA - American Gas Association

API - American Petroleum Institute

BS - British Standard Institution

CCR - Central Control Room

DC - Direct Current

DP - Differential Pressure

FAT - Factory Acceptance Test

GHV - Gross Heating Value

IP - The Institute of Petroleum

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IEC - International Electrotechnical Commission

ISA - Instrument Society of America

ISO - International Organization of Standardization

LCR - Local Control Room

MPMS - Manual of Petroleum Measurement Standard

NBS - National Bureau of Standard

NEC - National Electricity Code

PID - Piping and Instrument Drawings

RTD - Resistance Thermal Detector

SI - International System of Unit

SIRIM - Standard Industrial Research Institute of Malaysia

STC - Site Testing and Commissioning

1.5 CROSS-REFERENCES

Where cross-references to other parts of this PTS are made, the referenced sectionnumber is shown in brackets. Other documents referenced by this PTS are listed in (6).

1.6 ORDER OF PROCEDURES

In case of conflict between documents, the following priority of documents shall apply:

1. National or legal codes or regulations or binded contract between buyer and seller.2. The Purchase Order.3. The requisition, see PTS 32.32.00.93.4. This PTS5. Other PETRONAS, industry, national and international standards referenced herein.

Any conflict of requirements that cannot be resolved by the above order of precedenceshall be referred to the Principal for resolution.

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2. GENERAL REQUIREMENT

2.1 UNIT OF MEASUREMENT

The base (reference of standard) conditions for metering system shall be in SI units inaccordance with the ISO 1024 latest revision whose base conditions are defined as

pressure of 101.325 kPa (abs) at temperature 15o

C. Where imperial units such as barrelare required, it shall be converted from the base SI unit and referenced to 14.696 psia and60

oF.

Liquid hydrocarbon measurement shall be either in volumetric, mass or energy units. Theunits shall be SI units.

2.2 APPROVAL REQUIREMENT

Host country authority or the respective country petroleum resource managers approvalmay be required for measurement and allocation concept and metering projectimplementation as per items 2.2.1 and 2.2.2, respectively for the oil and gas production

facilities. Item 2.2.3specifies the government approval that is required to be compiled byContractors.

2.2.1 Measurement and Allocation Concept

2.2.1.1 Proposed Measurement and Allocation concept has to be submitted for the host countryauthority or their petroleum resource managers evaluation and approval for the oil and gasproduction facilities. The concept shall be submitted and agreed during the fieldDevelopment Plan Stage. Contractor shall carry out the financial exposure and cost benefitanalysis during the evaluation of the concept and to determine the location for theinstallation of the metering system, metering system configuration and level of accuracyrequired. To facilitate the above approval, the preliminary submission to the host countriesauthority shall include but not limited to the following items:

Measurement philosophy.

Product allocation principles.

Measurement methods and standards.

Proposed system accuracy.

Production accounting exposure analysis.

Metering project cost estimates.

Field area and installation layout with main pipelines.

Proposed sizing of the metering system.

Preliminary system configuration.

The metering system can either be used for Custody Transfer or Allocation purpose.

2.2.1.2 Two categories of metering system fall under the preview of these guidelines.

a) Custody Transfer Metering System

This type of system is shall be of high accuracy and designed with an uncertainty of+/- 0.25% of standard volume, used for custody transfer application i.e. transfer ofownership. The figure registered from this system is used for sales determination.

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b) Allocation Metering System

This type of metering has slightly lower accuracy than Custody Transfer Meteringand shall be designed with an uncertainty of +/- 1%. This type of system iscommonly used in oil and gas production facilities, used for allocation of liquidbetween field s of different ownership sharing a common facility or facilities. The

allocation method normally used is by full allocation i.e. where metering systemsare installed in all fields of different ownership involved in sharing the same facilities.However, the uncertainty of the metering system shall be designed to be of custodytransfer quality standard e.g. +/- 0.25% if measurement by difference allocationconcept being adopted.

Lowest level quality of Allocation Metering system can be of a well test systemsstandards (+/- 10%). Factors such as oil reserve, investment cost and impact to therelated parties are to be considered and agreed by those involved before thisallocation concept is adopted. This is applicable for oil and gas production facilitiesonly.

2.2.1.3 Generally two main measurement and allocation concept are currently acceptable for the

above purpose namely,

a) Measurement by different methodb) Full allocation

Only upon the host country authority agreement or the respective country petroleumresource manager on the measurement and allocation concept, Contractor can proceed onprocuring of the relevant metering systems in accordance to these guidelines. It is theresponsibility of the Principal to obtain agreement from their equity partner and theinterested party or parties that will be affected with the metering system installation, beforethe concept is submitted for host countries authority or the respective country petroleumresource managers agreement.

2.2.2 Metering Project Implementation

2.2.2.1 Host country authority or the respective country petroleum resource manager may alsorequest the following information to be submitted for approval for the oil and gas productionfacilities prior to the release of bid package:

a) System specificationsb) Design formula calculationsc) Calculation of overall accuracy and uncertainty of the systemd) Relevant drawingse) Other relevant information

They may also request the Project Definition Manual be submitted prior commencing

fabrication of the metering system.

2.2.2.2 Prior to the official use of the metering system, Contractor hall submit an applicationtogether with all relevant data for the respective host country to review and data submittedor after visiting the installation site. Metering system installed shall be traceable to thenational and international standards. For the case of the system in Malaysia, SIRIMBerhads directive is applicable.

Contractor shall also submit to the respective host country authority or their petroleumresource manager for approval, the hydrocarbon and accounting procedure and as well asthe validation procedure. The operation procedure will be requested on the need basis.

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2.2.3 Government Regulatory Requirement

2.2.3.1 Custody Transfer Metering System that registered flow quantity that is also used tocalculate the crude oil relevant tax needs to be agreed by the respective countriesgovernment authorities. For the system in Malaysia, it will be the Malaysian Authorities i.e.SIRIM Berhad and Customs and Excise Department. System to be installed shall be first

agreed by the authorities and certification from them is necessary prior official use. SeeAppendix 2for typical flowchart of the application.

2.2.3.2 Contractor shall also ensure that the necessary safety approval is obtained by theirVendors from the Government Safety Department should the fabrication and testing of themetering system be carried out in the country that requires this approval. Approval mayalso need to be obtained if the system is to be installed and operate onshore in certaincountries.

The government regulatory requirement may vary from country to country and Contractorshall ensure that the respective country regulatory requirements are being met.

2.2.3.3 Any deviations form these guidelines with respect to the measurement and allocation

concept, design, operation and maintenance of the metering system requires Principal priorapproval.

2.3 DOCUMENTATION

2.3.1 Contractor shall establish and maintain an up-to-date file containing all specifications,calculations and drawings (AS-BUILT). The file should also contain reports concerningverification revisions, design, fabrication, installation and commissioning includinginspection and testing programs and operation manual for all fixed and temporary phasesand other relevant documentation.

2.3.2 Contractor shall ensure that all documentation during the metering project implementation

are timely available such as the project definition manual including the uncertainty analysis,factory and site acceptance test procedures and its result and as well as validationprocedures.

2.3.3 The Contractor should maintain up-to-date lists of current documentation anddocumentation under preparation. Contractors internal control system including thedocumentation should also be made available to ensure qualities of the metering systemsare maintained.

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3. DESIGN OF METERING SYSTEM

3.1 GENERAL REQUIREMENT

3.1.1 The metering and proving systems shall be designed, fabricated, inspected and tested inaccordance with the latest agreed editions and addenda to the technical specifications,

codes, standards and references mentioned in (6).

3.1.2 Contractor shall request the vendor to quote for the design, manufacture, testing,calibration and documentation of a fully integrated skid and associated control panel.

The metering system shall comprise the following major component parts:

a) Field mounted skid, meter proving equipment and instrumentation.

The minimum number of parallel meter runs required from the specifiedmaximum and minimum flow rates at the specified accuracy with one completespare meter run. For allocation metering system having less critical availability,the spare run may not be required. It is on case-to-case basis.

A meter proving equipment and its instrumentation for regular proving andcalibration of the meter.

Flow proportional automatic sampling system. Refer to Section 3.7for details.

All associated pipe works, valves and fittings, access stairs, walkways foroperation, maintenance and validation, lifting pad eyes and drip pans.

All transducer and instrumentation necessary for automatic meter provingprover operation and continuous measurement of mass and volumetricquantities and flow rates of liquid together with its temperature, pressure,density and water content prior to delivery.

b) Metering control panel and computing facilities in the Control Room

The computer system consisting of the respective stream flow computingfunctions, meter proving computing functions, station computing functions andcommunication bus that will perform the calculation and computation ofquantities, reporting and metering system control functions. Station computerand communication bus shall be provided with full redundancy. For allocationmetering system will depends on the availability and criticality requirement ofthe system.

All other items not specifically mentioned but necessary for the functioning ofthe systems, including equipment for testing and calibration.

The control panel shall include all termination, computing devices, indicatorsand controls necessary for operation from the panel location.

3.1.3 All equipment within the skid shall be ergonomically arranged such that it is safe and easily

accessible for operation, maintenance and validation. Facilities to ease the validation shallbe included in the system. Platforms, gratings, stairs etc. be provided as required for easymovement within the skid area. For metering system that required heat tracing, allequipment and components that will be accessed periodically shall be provided withremovable insulating covers fitted with quick release fasteners. All equipment and materialsupplied shall be brand new and suitable to be used for its intended operating conditions.

3.1.4 The system shall be designed to allow subsequent re-calibration of the displacement prover(either sphere or piston displacer) on site with a portable master displacement prover master meter calibration equipment, tank prover-master meter or calibration can. Theflange connection size for the tie ins of the prover system must be suitable with therespective parties facility providing such recalibration services. For allocation meteringsystem where a master meter being used, a calibration facility for proving the master meter

shall be made available. Suitable process and electrical equipment and connections shallbe provided for the above purpose.

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3.1.5 No bypassing of the metering system is allowed for normal operations after commissioningand start up. For the purpose of commissioning and start up, should a bypass line isrequired, it shall be provided with a blind or a positive shutoff double block and bleed valvewith telltale bleed for verifying shutoff integrity. This valve shall always be sealed.

3.1.6 Other designs can be accepted provided that the Contractor can demonstrate and

document equivalent or better accuracy and integrity of the above mentioned system.

A typical flow schematic diagram is shown inAppendix 1of this guideline.

3.2 METER RUN DESIGN AND PIPE WORK METERING SKID

3.2.1 The meter runs shall be designed in accordance to the ISO2714, ISO 2715 and API Manualof Petroleum Measurement Standards Chapter 5 - Metering and other chapters as specifiedin (6). Materials selected shall conform to applicable codes, pressures and temperatureratings, process conditions, corrosion resistance, ingress protection and electrical safetyclassification.

3.2.2 Each parallel meter run shall be provided with an inlet, outlet stream control and prover inletvalves, thermal relief valve, flow meter with required upstream and downstream straightlength or flow straightening vane as required and a strainer with differential pressureindicator and draining facility. The strainer shall be able to handle the highest flowcapacities of the meter with a minimum pressure drop. Temperature transmitter andthermowell, pressure transmitter and pressure gauge shall also be provided. The number ofparallel meter runs shall be such that the metering system throughput with one meter runson standby and the remaining meters still operating within their working range. Forallocation metering system that is less critical, standby meter run may not be required.

3.2.3 A full bore through conduit or ball valve should be fitted upstream, downstream and proverinlets of each meter run.

3.2.4 Double block and bleed valves configuration with positive shut off for meter proving ormeter calibration and prover system calibration shall be fitted at the following places:

Meter runs outlets to prover inlet header

Meter run outlets to outlet header

Prover outlet to outlet header

Prover drains line.

These valves (with exception of the meter run inlet valve) shall have instrumentation for

cavity pressure relief and shutoff integrity verification. Drain connections from double blockand bleed valves configuration shall have an isolation valve and pressure gauge, forverification of tight shut-off. All drains and vents system downstream of the meter shall beof high integrity. For offshore metering systems, suitable arrangement for the valves tomeet the safety standards is to be followed.

3.2.5 Flow control valves shall preferably be located at the following points:

On each meter run outlet between the tee and the outlet double block and bleedvalve.

On the prover outlet between the 4-way diverter valve and the outlet double blockand bleed valve.

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The valves shall be capable to achieve a stable flow rate control at a flowrate requiredduring meter proving and calibration over at least the normal linear range of the meter.Valve and actuator sizing calculations shall be required as part of the documentation.

Should during operation, a stable flow could not be achieved over normal operating rangeof the meter, the interest parties including the host country authority may agree on an

acceptable reduced range for meter proving. However, the meter shall not be operatedbelow 20% of the meter maximum rated flow rate.

3.2.6 Thermal relief valves shall be provided for all sections of pipe work capable of isolation andpossible over-pressure. All connections shall be self-draining. The total pressure drop ofeach meter run at the maximum linear operating conditions shall be provided.

3.2.7 Maximum pressure drop across the metering system shall be 2 bar and 2.5 bar when meterwhen calibration is in progress. The operating pressure of the metering system shall beabove the vapour pressure of the liquid and a single liquid phase is to be maintainedthroughout the measuring process. It is necessary to check further with the processengineers that the designed pressure drop will not caused any problem to the downstreamequipment of the metering system.

3.3 FLOWMETER TYPE

Careful considerations such as the liquid viscosity, flowrate and the liquid conditions needto be taken in selecting the appropriate flowmeter. Some meter is only limited to certainviscosity ranges and not suitable for high viscosity. Other factor such as the ability for in situproving shall be considered. The authority in certain countries may approved certain typesof flowmeter only and should the flowmeter intended to be used has not been approved forCustody Transfer and Allocation purpose, it is the responsibility of the Contractor to getprior approval prior of the project implementation.

The meter shall be calibrated initially, preferably on the liquid with the viscosity for which

the system is designed, or if unavailable, on water at the factory and a certificate is to beissued.

3.3.1 Turbine Meters

For technical specification of turbine meter metering system, please refer to PTS32.32.00.11.

The turbine meters shall be equipped with two pick up coils each of which shall be fittedwith a preamplifier and is independent of each other, in accordance with Level A of the IP252/76 Code of Practice. This is to indicate whether the signal is good or bad and to alarmthe operator of a possible meter or pulse transmission failure.

The repeatability of the meter factor shall be better than 0.05% (band) within linear rangefrom five (5) consecutive runs.

The linearity of each meter shall be within +/- 0.25% over the specified Normal operatingflow range and for the full range of viscosities specified i.e. the complete family ofcalibration curves for all viscosities within the specified Normal operating flow range shalllie within the envelope of +/- 0.25% of the average between the highest and lowest meterfactor at the specified viscosity. The vendor shall provide, in his proposal, typical meter testreports for the type and size of meter offered over the specified viscosity range.

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3.3.2 Positive Displacement Meter

The positive displacement (PD) meter is to be used when the turbine meters could notmeeting the conditions of the medium such as high viscosity for it to operate. Double casingtype of PD meter should be used for high pressure application to minimize the effect ofpressure in volume of the measuring chamber of the meter. The required repeatability and

linearity for the meter is similar to that of a turbine meter. Alternatively, a helical turbinemeter can also be considered to be used at high viscosity medium.

The proving requirement for the PD meter is also similar to that of the turbine meter. Thepulse generator selected must be capable to provide sufficient pulses required i.e. 10,000pulses (unaltered) for a single trip when proving using conventional pipe prover.

3.3.3 Other types of Meter

The use of other types of meters such as the Coriolis Mass flowmeter and Liquid Ultrasonicmeter may require the Principal to be consulted. Proving of this meter at site need to betaken into consideration when this type of meter is to be selected.

3.4 METER PROVING SYSTEM DESIGN

A permanent meter proving facility shall be provided and be designed as per ISO 7278Liquid Hydrocarbons - Dynamic Measurement - Proving Systems for Volumetric Meters andAPI MPMS Chapter 4 - Proving Systems and Chapter 4 of API Manual. Meter provingfacility can be using any of the following methods.

The capacity or size of the prover shall correspond to the maximum flow range of the flowmeter.

3.4.1 Displacement Prover

A displacement prover includes a calibrated section in which a displacer (sphere or pistondisplacer) travels with the flow, activating detection devices (mechanical switches or theoptical switch). All types of displacement prover systems operate on the principle of therepeatable displacement of the known volume of liquid are achieved by an oversizedsphere or a piston travelling through the pipe. The liquid flow is not interrupted during meterproving. This uninterrupted flow permits the meter to be proved under specific operatingconditions and at a uniform rate of flow without having to start and stop.

Generally, displacement prover can be categorised as follows:

Conventional pipe prover

Small volume prover

3.4.1.1 Conventional Pipe Prover

For detail technical requirement on technical specification of turbine metering system,please refer to PTS 32.32.00.11.

The Conventional Pipe Prover shall preferably be of the bi-directional type with quickopening closure for sphere removal, sized and manufactured in accordance with ISO 7278-2 Liquid Hydrocarbon - Dynamic measurement - Proving systems for volumetric meters -Part 2: Pipe Provers, API MPMS, Chapter 4.2 - Manual of Petroleum MeasurementStandards Chapter 4 - Proving System Section 2 - Displacement Provers and the followingcriteria:

Number of meter pulses generated over calibrated volume to be not less than 10,000whole pulses (unaltered) per trip i.e. 20,000 pulses (unaltered) total round tripvolume.

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Resolution of detector/displacer system shall be compatible with requirement (1).

Displacer velocity shall not exceed 3 m/s to avoid slippage around the displacer.

Length between detector switches to be at least 20,000 times detector repeatability.

Prover connection shall be downstream of the meters.

The prover shall be designed such that the repeatability during calibration of thevolumes, where five calibration trials i.e. 5 consecutive round trips are performed andbe within +/-0.01% of the average volume.

Connections shall be provided on the prover loop to facilitate recalibration with aportable master pipe prover-master meter or tank prover-master meter. Drain at thelowest point and vent at the highest point shall also be provided. The prover systemshould also equip with temperature and pressure measuring element.

Other considerations for the design including the followings:

a. Detector switches

The pipe prover shall have two detector switches at each end of the prover withpreferable four independent calibrated prover volumes. The prover volumesfrom the cross-sectional installed detector switches shall be very similar andthese calibrated volumes are to be independent of each other where at any onetime if either one of the detector switches fails, it does not invalidate the otherprover volume.

The detector should be designed such that the contacting head of the detectorprotrudes far enough into the prover pipe to ensure switches takes place at allflow rates during calibration and normal operation. Detectors and switchesshould be weather proofed against corrosive marine environment and suitablefor the electrical safety classification of the installation.

b. Prover Internal and Coating

Internal diameter of the prover loop shall have the same diameter throughoutand there shall be no tapping or drain points between the calibrated volumes ofthe prover.

The internal coating of the pipe prover shall provide a continuous level, durableand smooth surface for the application. The vendor shall provide full details ofthe coating, surface preparation, method of surface preparation, method ofapplication, maximum allowable fluid temperature and method of repair.Porosity and explosive decompression of the lining shall also be avoided.

c. Four-way Diverter Valve

The four way diverter valve shall be motorized and provided with a local andremote actuation together with a manual override handwheel. Limit switchesshall be provided for remote status of valve. Necessary instrumentation todetect leakage on the valve is also to be equipped. The 4-way flow divertervalve in the bi-directional prover shall be full seated and sealed before displacermeets the first detector.

d. Freedom from Shock

When the prover is operating at its maximum design flowrate the displacer shallcome to rest safely at the end of its travel without shock.

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A means of positioning and launching the displacer upstream of the calibrated section.

A displacer detector(s).

A valve arrangement that allows fluid flow while the displacer is travelling from oneposition to the opposite position.

Pressure measurement and indication devices.

Temperature measurement and indication devices.

Instrumentation with timers counters and pulse interpolation capability.

3.4.1.2.6 During proving of Turbine and Positive Displacement meters, the displacer velocity shouldnot exceed 1.5 m/s. The internal diameter of the prover flow tube shall have the samediameter throughout the flow tube. The calibrated or swept volume of the prover, locatedbetween the displacer-position sensors shall be free from any tapping, vent or drain points.

3.4.1.2.7 The small volume prover should be installed downstream of meters. The small volumeprover shall allow the displacement to come to rest safety without shock at the end of itstravel when operating at its maximum design flow rate. There shall be no sign of cavitationsin the small volume prover, the valves or any other apparatus within the specifictemperatures and pressure ranges when operating at its design maximum flow rate.

The internal coating of the small volume prover shall have uniform bore, durable andsmooth lasting surface.

Block valve shall be installed to isolate the small volume prover from line pressure duringmaintenance, removal of displacer, replacement of seals, cleaning etc.

Drain at the lowest point and vent at the highest point shall be provided. Pressure relief

valves and leak detection facilities shall be installed with discharge piping to controlthermal expansion of the liquid in the small volume prover while it is being isolated from themain stream.

3.4.2 Master Meter Prover

A Master-meter is an indirect prover that uses the concept of transfer proving. A flowmeterwith exceptional linearity and repeatability is selected to serve as a master meter(Intermediate Standard) for the proving of another meter or prover operating in the field. Acomparison of the two outputs is the basis of the master-meter proving method.

3.4.2.1 The master-meter prover shall be manufactured in accordance with ISO 7278 LiquidHydrocarbons - Dynamic Measurement - Proving Systems for Volumetric Meters and the

API Manual of Petroleum Measurement Standards Chapter 4 - Proving Systems, Section 5- Master-Meter Provers.

3.4.2.2 Master-meter proving, of which satisfactory results can be achieved, is used in situations inwhich proving by direct method cannot be accomplished because of logistic reasons, suchas unavailability of provers. However, the Master-meter method introduces uncertaintiesbetween the meter being proved and the prover that is used to calibrate the master meter.Master-Meter Provers shall be used on a less critical metering system.

3.4.2.3 The master meter should be placed downstream of the meter to be proved and shall beconnected in series and close enough to minimise corrections for volume during proving. Allfluid diverting valves between the meters shall provide a positive seals.

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The master-meter provers shall be manufactured in accordance with the API Manual ofPetroleum Measurement Standards Chapter 4 - Proving Systems, Section 5 - Master-Meter Provers.

If the master-meter is in portable service, it should be protected against damage duringtransportation, installation and handling.

3.5 METERING SKID AND CONTROL ROOM INSTRUMENTATION

3.5.1 Field Instrumentation

3.5.1.1 Location of Sensors

Temperature and pressure shall be measured in each meter runs and at the inlet and theoutlet of the pipe prover.

3.5.1.2 Installation of Instruments

A thermowell shall be installed adjacent to every electronic temperature sensor or group ofsensors for calibration. It shall be possible to connect test instruments in parallel with allpressure sensors in the metering system. Temperature, pressure and density, wherespecified, measuring points shall be representative of conditions at the meter and situatedas follows:

In volumetric measurement systems: as close to the meter as possible withoutinfringing the requirements of the API Measurement manual or other standards asspecified in this guideline.

In mass measurement systems: as close to the densitometers as possible, whichshould also be located as near the meter as possible, without infringing the APIMeasurement Manual or other standards as specified in this guideline.

3.5.1.3 Instrument Loops

The instrument loops shall be kept separate from other types of instrumentation and powersupply cabling in the area of use. Cables and junction boxes shall not be shared withinstrument loops that are not part of the metering system.

Cables and other part of the instrument loops shall be designed and installed so that theywill not affected by electromagnetic fields.

3.5.1.4 Transmission of Pulse Signal

Pulse signal transmission and treatment from the turbine meter shall be designed inaccordance with guidelines in IP252 or ISO 6551.

A pulse comparator shall be installed which signals an alarm when a pre-set number oferror pulses occurs on either of the transmission lines in accordance with the above code.The pre-set level should be adjustable and when an alarm occurs it should be recorded ona non-resettable comparator register. Where the pulse error alarm is determined by anerror rate, the error threshold shall be less than 1 count in 100,000.

Pulse discrepancies that occur during the low flow rates experienced during meter startingand stopping should be inhibited. The pulse transmission to the prover counter should befrom one or both of the secured lines to the pulse comparator and precautions should betaken to avoid any signal interference in the spur from the comparator line.

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Internationally accepted pulse interpolation methods for the pulse signals from the turbinemeters may be used if it can be proved that the accuracy of the metering system satisfiesthe requirement in this article and satisfactory documentation of the reliability for theinterpolation is produced.

3.5.1.5 Conversion of Signals from Analog to Digital Form

The A/D conversion shall not contribute systematic errors to the measurements. Totalinaccuracy in the analog to digital conversion, including resolution, drift, linearity,repeatability and other random errors shall be less than +/- 0.025% of full scale.

Where a signal A/D conversion is used, back up converter is required.

3.5.1.6 Temperature Measurement

The temperature measuring element shall be a platinum resistance element Pt-100Platinum RTD element 100 ohms at 0

oC with temperature transmitter in accordance with

guideline in IEC 60751 Tolerance Class A or equivalent. The accuracy for the completecircuit shall be better than +/-0.15

oC.

3.5.1.7 Pressure Measurement

The accuracy for the complete pressure loop shall be better than +/-0.25% of span.

3.5.1.8 Density Measurement

The density measurement where specified, shall be designed in accordance with IPPetroleum Measurement Manual Part VII Section 2 or API Manual of PetroleumMeasurement Standard, Chapter 9.

For mass measurement, two density transducers should be installed. The installation shallbe such that the liquid passing through the density meter is representative of the linedensity and no gas can be trapped in the density meter that could cause the error on thedensity reading. They should both be installed at the inlet to the metering system, withinthe fast loop arrangement. Insertion type densitometers may be installed in the inlet oroutlet of the metering system.

The densitometers installation should be in such that one can remain online for densitymeasurement continuously while the other one is taken out for maintenance/validation.Necessary correction to meter conditions shall be carried out. The built-in temperaturesensor in the densitometer shall only be used for indication purpose.

The accuracy for the complete loop shall be better than +/- 0.5 kg/m3.

3.5.1.9 Control Room Instrumentation

Environmental

Instruments which are sensitive to temperature or other environmental factors shall beinstalled in locations where these factors can be controlled.

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3.6 METERING COMPUTERS AND CONTROL SYSTEM REQUIREMENTS

3.6.1 General

Metering and meter proving shall be managed by a computer system. Manual proving shallalso be incorporated as a backup. This system shall be installed in the CCR, LCR or local

equipment room. Flow computers shall be dedicated for each meter run for CustodyTransfer Metering System. The station computer and the prover computer shall be able toperform the station function and also the proving function. However, the number ofcomputers may be reduced if it can be demonstrated that the required reliability, availabilityand redundancy standards will be met.

For detail technical requirement on technical specification of turbine metering system,please refer to PTS 32.32.00.11.

3.6.2 Computer System Design

The computer system is to be designed as follows:

3.6.2.1 The computer in the metering system shall have no functions other than those related tothe metering. The metering system shall be designed in such a way that the maximumliquid flow will be measured.

3.6.2.2 The computer part shall have the capability of displaying continuously the number of pulsesreceived from the meter during proving.

3.6.2.3 The system should include at least two independent registers for storing accumulated fiscalquantities for each meter run and the station total. It shall not be possible to delete orchange these registers by operator encroachment or power failure.

3.6.2.4 The computer shall also be designed to ensure that flow quantity measured duringvalidation/calibration i.e. simulation quantity are registered separately from the actualmeasured amount (during maintenance mode).

3.6.2.5 Manually entered parameter shall be displayed without rounding off or truncation of digits.The display on the computer shall have sufficient resolution to enable the verification or thecalculation accuracy as in Section 3.6.4be carried out.

3.6.2.6 Computer system shall be designed such that the transfer of data to DCS/SCADA/PlantInformation (PI) System is permissible and all interfacing requirement such as thehandshaking and necessary software is provided.

3.6.2.7 The computer part shall have automatic watch over for differences between readings forcontinuous monitoring of measurement data the computer shall, for each meter run,

automatically log and store for at least one year the following data; At internals of 1 hourcumulative quantities, meter factor and average values of pressure, temperature anddensity. At intervals of 24 hours: cumulative quantities. This information shall be accessibleon printout in a clearly set out format using standard computer printer and paper. Access tothe logs shall not be possible without the use of key operated switch.

3.6.2.8 The flow computer shall (standard feature and without further modification) be able toreceive at least 2 pulse trains from a turbine meter to perform the pulse security check inaccordance with the guidelines stated in the IP 252 or ISO 6551.

3.6.2.9 Report facility for computer constants, keypad setting should be available.

3.6.2.10 The computer will have the ability to perform meter curve (foot-print) interpolation for

minimum of 8 calibration points.

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3.6.3 Data Security

The data transmission of the computer shall be designed in accordance with Level A of theIP Standard 252/76, Part XIII Section 1.

The computer shall have a self diagnostic capability. It shall monitor that the program loops

are executed at the correct intervals by means of a watchdog function.

The parts of a memory that contain permanent data shall have a periodical check sumcontrol.

The algorithms and the fixed parameters important for accurate computation of fiscalquantities shall be stored in non-alterable memory.

Security system shall be provided for manual entering of data. The computer system shallbe designed and features provided for sealing.

Program version number shall be assigned to identify the current program used and thiscan be determined directly from Visual Display Unit (VDU) or print out. The version number

can be updated every time permanent program is altered.

3.6.4 Calculation

The computer routines for fiscal measurement calculation shall satisfy API MPMS Chapter12 - Calculation of Petroleum Quantities and IP 201 Petroleum Measurement Manual Part1 - Calculation of Oil Quantities.

a. Update time to changes of input signals shall not be more than 2 seconds andparameters having response time such as density and temperature shall not exceed 5seconds.

b. The interval between each cycle for computation of instantaneous flowrate andaccumulated flow shall be less than 10 seconds.

c. The algorithms for calculation of meter factor at reference condition shall contain allcorrection factors given in API 2534 1

stedition 1970.

d. Algorithm and rounding off error for computation of fiscal quantities in the flowcomputer shall be within +/- 0.001 % for totalisation and +/- 0.01% for flowrate of thecomputed value. Rounding or truncation shall only be carried out at the end of finalcomputation.

e. Temperature reading in degree Fahrenheit (deg F) shall be corrected to 1 decimalpoint and 2 decimal points for reading of temperature in degree Celcius (

0C).

f. For meter factor and volume prover computation purposes, the decimal points usedshall follow the API PMS Ch. 12. However, the requirement of some countries woulddiffer e.g. in Malaysia.

Ctl, Cpl, Cts and Cps - 6 decimal points

Prover volume calculation - 4 decimal points

Meter factor - 6 decimal points

Final prover volume shall be corrected to 3 decimal points.

Deviation from the respective country requirement would require approval from therespective country authority or the respective country petroleum resource manager.

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3.6.5 Printouts and Hardcopies

The computer system shall have dedicated printers for alarms and reports. Supervisorycomputer should be able to electronically archive all the alarms and reports. Commonprinter can be used if an acceptable priority routine is established. Automatic logging onthe following information is to be provided:

Alarms for faults detected by the computer (date, time).

Inserted parameters/constant, both fixed and changeable. Old and new manuallyentered by operator shall also be printed out.

Quantity report.

Instantaneous values of rate and measured input parameters. Fixed values, which areused instead of live signals, shall be identified.

Meter proving report. All data required for manual checks of calculated correctionfactors and meter factor shall also be included.

The Contractor shall consult the respective country authority to establish a system forreporting of agreed data.

3.6.5.1 Printouts for continuous measurement system

The computer system shall automatically generate the following reports intervals but shallalso be able to suppress the printing of the reports.

Current status (instantaneous values)

Hourly report

Daily sales and production report (Normally daily sales report is at 00.00 hrs and 06.00hrs for production report).

The generated quantity report shall consists of the following information as minimum:

Current flowrate current process data and average process data (average values shallbe flow weighted)

All totals.

3.6.5.2 Printouts for batch measurement system

The computer system shall automatically generate the following reports intervals:

Current status (instantaneous values)

Hourly report

Batch start and end report.

Other reporting requirement, similar to 3.6.5.1.

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3.6.6 Meter Proving Algorithm Routine

During designing the computer routine for meter proving operations, the followings shall befollowed:

a. All meter runs outlet and prover inlet valves and status check for meter proving

sequencing shall be automatic.

b. All proving calculations shall be carried out by the computer system and printedautomatically. Sufficient data shall be available on the printout such that meter provingcalculations can be verified externally. Repeatability limits and the required number ofconsecutive run for repeatability acceptance shall only be changeable with highestsecurity level (meters repeatability shall be such that they can be calibrated against apermanent meter prover with a sequence of 5 consecutive runs, where the differencebetween the highest and lowest meter factor does not exceed 0.05% of the averagemeter factor).

c. Maximum trial runs before the computer aborts the proving operation shall also bemade changeable with highest security level (default number of trial runs is 10).

d. Prover stabilization period for process conditions i.e. temperature, flowrate, pressureparameters of the stability limit shall be user changeable with appropriate security level(supervisor/engineer).

e. Automatic loading of meter factor to flow computer upon confirmation from operator.Acceptable meter factor shall be within the meter factor high and low limit of therespective meter.

3.6.7 Power Supply

The computer shall be equipped with an uninterruptible power supply (UPS) system forback up purposes. Normal operation of the metering system shall not be affected if there isany change from one power source to another.

3.7 SAMPLING AND ANALYSIS REQUIREMENT

3.7.1 The metering system shall be provided with automatic flow proportional sampling system tocollect representative sample for the determination of BS&W, average density and for otheranalysis purposes. Manual spot sampling for back up purposes shall also be madeavailable. The sampling system shall be designed in accordance with guidelines in IPPetroleum Measurement Manual Part VI Sampling Section 2, ISO 3171 and API MPMSChapter 8 of latest edition.

3.7.2 As sampling system for the determination of water content is critical especially in upstreamactivities which eventually determined the net production, due attention must be given tothe design and operation in ensuring a representative sampling.

3.7.3 For Custody Transfer System, sampler controller and sample monitoring unit shall beinstalled. It is also recommended to be installed on allocation metering system especiallywhere the sampling system become more critical. The control unit should be able tomonitor the sample volume collected continuously. Receiver to be sized to allow 10,000grabs per sample period with 80% filling range with minimum grab size of 1 ml. Thesampling cylinders or receivers should be installed in a cabinet and be located as close aspossible to the sampling point.

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3.7.4 Selection of sampling point shall be such that the pipeline condition at the selected point ishomogeneous. Contractor need to demonstrate by calculation whether additional mixingrequirement such as static or jet mixer is required to ensure homogeneity of the liquid priorsampling. Additional precautionary measures are to be taken if the amount of waterpresence in the fluid is quite high.

3.7.5 The sampling system should be located near to the metering station.

Where slugs of water may be experienced, inline water detection probe shall be fitted todetect abnormal levels of water content.

For sampling of pressurized liquids, the following should be observed.

Pressurized cylinders shall be lightweight.

Prior extracting of the liquid either for further transportation or analysis, the samplesshall be representative and can be achieved through internal mixing in the cylinder.Integrity of the samples is to be maintained throughout the exercise.

For pressurized manual sampling, appropriate sample point and sampling cylinder forpressurized liquid is to be used and to ensure that no lighter components of the fluidable to be liberated out of the cylinder.

3.8 METERING DATA AND REPORTING

All the metering data should be made available at hourly/daily and on request basis.

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4. TESTING, CALIBRATION AND COMMISSIONING

4.1 GENERAL REQUIREMENT

4.1.1 Prior to site installation, a Factory Acceptance Test (FAT) shall be conducted to check the

integrity of both the computer software and the mechanical/skid instrumentation. FATprocedures shall be agreed between Contractor and the Vendor prior to the test.

4.1.2 During FAT, the electronic and the mechanical instrumentation shall be tested together.Prover system need to be first calibrated and witness by a third party before flow integrationtest be carried out. It is essential that the vendor shall demonstrate that the equipment wasinternally tested and in good working order before the Contractors representative areinvited for the test.

4.1.3 All FAT results are to be fully documented. Only after successful completion of the FAT canthe metering system be accepted and shipped out to the site. On site, further testing shallbe carried out prior to the commissioning of the system. All calibration equipment used forthe SAT shall be traceable to the respective countrys National and International standard.

In Malaysia, it has to be traceable to Malaysias standard where SIRIM Berhad is theCustodian. It is the responsibility of the Contractor to ensure that the FAT and SiteAcceptance Test (SAT) procedure be made available prior to the tests. The host countryauthority may request these procedures to be submitted for review and also to witness thetest. The host country authority shall be notified at least three weeks prior to both tests.

4.2 CALIBRATION

4.2.1 General

Liquid Hydrocarbon Custody Transfer and Allocation Metering Systems shall be calibratedwith test equipment having certified traceability to international or national standards. Theuncertainty of this equipment shall be better than the uncertainty of the metering equipmentit used to calibrate.

Secondary standards or instruments used for calibration of all relevant parts of themetering system shall be calibrated and certified by the respective countrys Metrology unit(SIRIM Berhad for equipment to be used in Malaysia) or any other independent laboratorywhich can prove such traceability.

4.2.2 Instrument Calibration

All relevant instruments used in the metering system shall be calibrated and certified by themanufacturer which can prove such traceability.

4.2.3 Prover Calibration

The proving system shall be calibrated at the vendors works as part of their system checksand after installation on site, immediately prior to start up. Comparison on these twovolumes will be done for checking purposes. The detail calibration method used willdepend on the type of meter proving system. Prover calibration procedure shall be madeavailable prior to the exercise.

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4.3.2 Factory Acceptance Test (FAT)

4.3.2.1 General Check

Prior to further test in the factory, a general check on the system is to be carried out. Thisincludes checking of the following items.

a. Dimension check as per approved drawings and standards.

b. Instrument installation and quantity check as per approved drawings and bill ofquantity respectively.

c. Availability of all documents.

4.3.2.2 Metering Panel and Instrumentation Equipment Tests

4.3.2.2.1 All panel and field mounted instrumentation, cabling and the connectors shall be visuallyinspected for compliance with specifications with regard to segregation of cables,satisfactory access, vents, drains and general good quality of installation work.

4.3.2.2.2 Calibration checks using precision test equipment shall be performed on all transducers,transmitters, converters, indicators, recorders, gauges and switches etc. supplied for usewith the system.

4.3.2.2.3 All safety and relief valved shall be tested, set and tagged with the set pressure.

4.3.2.2.4 An insulation test shall be made on all power supply and instrument cables and panelwiring using voltage tester. Instruments shall be disconnected during this test which maycause internal damage. All resistance thermometer elements shall be tested for insulationresistance to BS-1904.

4.3.2.2.5 A sample of the power circuit breaker shall be tested by simulating a short circuit failure.

4.3.2.2.6 The control panel shall be fully functionally tested before connection to the skid usingappropriate simulators and other test equipment. These tests shall include:

Panel mounted receiving indicators etc.

Outputs from panel mounted controls.

Meter run and prover instruments.

Computer functional test.

Verification of computer calculation and integration accuracy as specified in item 3.6.

Interlock and alarms.

Checking of power distribution circuits and breakers for correct wiring.

Analogue functions shall be calibrated at a minimum of five points rising and fivepoints falling in the range (0%, 25%, 50%, 75% and 100%).

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a. All meters shall be individually flow tested and proved against the prover at their ratedmaximum and minimum flows on five points at specified intervals between maximumand minimum. Each point shall consist of five consecutive runs, the results of whichthe difference between the highest and lowest meter factor does not exceed 0.05% ofthe average meter factor.

b. The linearity must be within +/-0.25% over the specified Manufacturer design flowrange. Observations shall also be made and recorded of:

Pressure drop across strainer.

Pressure drop across meter run.

Pressure drop across prover.

Density measurement (if applicable).

c. Checks shall be made during testing for tightness of shut-off high integrity and thefour-way diverter valves.

d. All meter runs shall preferably be flow tested simultaneously (i.e. one metering andone proving) and preferably up to the normal maximum linear capacity of each meter.

e. Checks shall be made on the functioning of the flow control valves.

f. Checks shall be made on the correctness of the meter proving algorithms.

g. Checks shall be made to ensure correct reports such as meter proving report andmetering report (hourly or batch report) generated by the computing system.

h. Checks on the correct functionality of the sampling system to ensure volume collected

and accuracy as per number of grabs, accuracy of sampling system, alarms andswitching of sampling cylinders.

4.3.2.3.2 Following completion of the flow testing, the liquid test medium shall be drained and athorough inspection be carried out on the condition of prover lining and other equipmentwhere possible.

4.3.2.3.3 Computer simulations shall be carried out whereby all calculations by the computingsystem shall be verified.

4.3.2.4 Site Acceptance Test (SAT)

4.3.2.4.1 The Contractor shall provide test procedures for punch list items arriving on site. Other

items to be provided shall include but not limited to the following:

Loop diagram and loop checkout sheets

Full print data base checking

System functional test procedure and schedule

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4.3.2.4.2 The onsite acceptance test shall be considered as an extension of the FAT. Prior to SAT,all wiring termination to be checked and powering of the panel should be carried out by thevendor or authorized vendors representative. Some tests carried out during FAT shall alsobe repeated during SAT. SAT on Custody Transfer Metering System that involved exporttax computation which the government have interest in, should be witnessed by thegovernment or the host country representative e.g. SIRIM for the installation in Malaysia.

SAT shall concentrate more specifically on the following:

a. Inspection of material and equipment on arrival at site including spares anddocumentation. If damage occurred during transport, it is important to establish withoutdelay, the extent of the damages and whether it is repairable onsite or necessary toorder new materials.

Suitable storage of material and equipment should be provided.

b. Field calibration of the pipe prover shall be in accordance with API Manual ofPetroleum Measurement Standard Chapter 4 Meter Proving and the requirementsstated in these guidelines. All calibration equipment used for prover and other meteringequipment shall be traceable to National standard.

All prover calibration on Custody Transfer Metering system that involved export taxcomputation shall be witnessed by Contractor and SIRIM for metering installation inMalaysia.

c. The metering panel and instrumentation equipment test shall be repeated which alsoincludes the computations check carried out by the computer system. The calibrationexercise carried out on the instrument in this exercise is considered as Validation No 1.

d. The completed meter skid and panel shall be subjected to operational functional testduring actual flow condition to demonstrate satisfactory performance at the designflowrates.

4.3.2.4.3 Contractor shall submit project completion report, which should include the first officialvalidation report to the host country authority should it be required within 30 days aftersystem has been commissioned. Before the system is put in operation for official use,approval from the respective host country authority shall be obtained.

4.4 COMMISSIONING

4.4.1 General

The installation, commissioning and start-up of the metering system shall be carried out inaccordance with the requirements in this section.

4.4.2 Installation Quality Assurance

The Contractor shall set up an installation and commissioning plan of a system of activities,the purpose of which is to provide assurance and show evidence that the overall qualitycontrol shall be effectively maintained.

The plan shall be applied systematically to all metering systems, and deviations will not betolerated.

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4.4.3 Commissioning

Commissioning shall include running-in of all rotating equipment, checking alignment,testing control loops, stroking valves, flushing, hydrotesting, final testing of electricalinstrumentation systems, purging, drying, inerting etc which usually carried out sequentiallyon a system basis. Commissioning is completed when the metering system is ready for

start-up.

4.4.4 Start-up

It begins with the introduction of process hydrocarbon into the system excluding the periodwhere hydrocarbon may have been used previously for pressure testing/purging.

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5. OPERATION, VALIDATION AND ACCOUNTING

5.1 GENERAL REQUIREMENT

Contractor shall operate and maintain the metering system to the highest degree ofengineering standard in order to maintain its accuracy and integrity. As such, operating,

validation and accounting procedures/manuals shall be prepared by the Contractor andapproved by the respective host country authority or the host country petroleum resourcemanager wherever applicable before start-up. (In Malaysia, the approval party isPETRONAS being the petroleum resource manager and authority of the ProductionSharing Contract) These procedures shall document all activities that influence themeasurement system.

5.2 SYSTEM OPERATION

Contractor is required to carry out the following essential activities:-

5.2.1 Metering stations shall be operated and maintained in accordance with the manufacturer

recommendations and approved operation, validation and hydrocarbonallocation/accounting procedures. Metering validation is to be performed as per the agreedvalidation procedure using equipment that is traceable to National and InternationalStandard.

All factors, constant, key pad values and limits used in the metering system either used forcomputations, checks or alarms shall be updated regularly. When the metering equipmente.g. the density meter and the flowmeter is changed, all the respective factors for densitycalculation, Meter K Factor, Meter Factor etc. Need to be updated. Upon successful meterproving, the new meter factor shall be updated in the computer accordingly.

During meter proving, particular attention shall be given to flow stabilization prior to meterproving, checking of block and bleed valves for leaks and venting at high points.

a) Meter Proving Operations for continuous Flow Measurement System

For a newly commissioned metering station with a dedicated meter proving facility in acontinuous production system (as distinct from tanker loading), meters shall be provedtwice a week at approximately equal intervals between proving. Provided the meterfactor scatter is acceptable and until a meter factor control chart is established, thefrequency may be reduced to once a week or on monthly basis. The frequency forproving may be further reduced upon agreement between the host country andContractor where applicable.

Where meter factor linearization curve is being used, the curves linearity shall be withinthe normal meter operating flow range and is within +/- 0.25%.

b) Meter Proving Operations for Batch Measurement System

For tanker loading systems, any meter onstream shall be proved at least onceregardless of the duration of loading. Additional proving is required on stream(s) whereconditions of loading. Additional proving is required on stream(s) where conditions suchas the flow rate have changed and a prove required alarm is triggered and this newfactor shall only be used on the new flowrate.

5.2.2 Where meter types other than mentioned in this guideline, the type and frequency of meterproving by the Contractor shall be determined on an individual basis by the host countryauthority after consultation with the Contractor. Account shall be taken on the meter type,

process fluid and operational load cycle. Where meters employing novel technology are tobe used, extra evaluation periods and tests will usually be required before a long-termoperational schedule can be determined.

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5.2.3 Meter factors that are acceptable for use shall be based on the repeatability acceptancecriteria of not more than 0.05% of five consecutive runs. Meter factor control chart is to bedeveloped and Meter Factor High and Low limits be established used to verify theacceptability of the meter factor.

5.2.4 Pipe provers and small volume provers shall be calibrated at least once a year. Where this

is not possible for operational or whatever reasons, longer calibration interval may beconsidered by the respective host country authority. Inspection of the sphere, checking ofsphere size, concentricity etc should take place prior to calibration. After calibration, thesphere detectors and switches shall be sealed.

Any maintenance work on the prover that could affect the swept volume e.g. changes ofsphere detectors and switches should not be undertaken without prior consultation with thehost country authority who will advice if a calibration is required.

5.2.5 Operating Manual

The Operating Manual shall be prepared for the purpose of providing operational guidelinefor the operators in performing metering activities. It shall then be describe the operation of

the system which includes the computers, the skid instrumentation, sampling activities andother operation of the metering system.

The manual among other things shall also include what actions to be taken in case ofmalfunction or alarm on the metering system.

The minimum content of the manual shall consist of the following:-

Overall process description.

Metering system description.

Metering instrument specification.

Computer system operation (including the computer read codes) and actionstaken on alarms.

Metering system operation.

Metering sealing procedure.

Sampling procedure.

5.3 SYSTEM VALIDATION

In order to maintain the reliability and accuracy of the metering system, Contractor shallconduct a periodic calibration and validation of the metering system at a frequency agreedby the respective host country authority. For new systems, a monthly validation shall beperformed. A new validation frequency can be agreed with the host country authority aftersuch time the system is stable. The calibration/validation shall be performed in accordancewith the agreed system Validation Manual.Contractor should consider installing the validation software application in its computersystem which will facilitate further the validation exercise.

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All validation result shall be recorded on the format agreed in the Validation report. Thereport shall include but not limited to the following:-

As found and as left result of the calibration exercise.

System uncertainty in accordance with ISO 5168 latest revision.

Findings and recommendations.

Metering irregularities occurred since then and between the last validations.

Validation reports shall be prepared after each validation and submitted to the host countryauthority within 1 month. Any irregularity on the figures generated, resulting from thevalidation shall be endorsed by the respective host country authority.

5.3.1 Validation Manual

The validation Manual shall be prepared for the purpose of providing guideline for theverification of the metering system instrumentation. Contractor may consider including thescope for the metering vendor to also provide the validation manual in its documentationsubmission. This manual shall be ready prior to the official use of the metering system and

approved by Principal and also the host country authority. The content of the validationmanual shall consist of, but not limited to the following:

5.3.1.1 Brief description of the metering system.

This shall include a concise description of the design concept of the system and itsinstrumentation including the computer system. Description as to the function of eachindividual instrument in the system, its accuracy and location in the system layout, systemcapacity, flow operating condition and the schematic drawing of the system, instrumentdescription shall include manufacturers name and model number, range, accuracy,input/output signal and tag number.

5.3.1.2 Calibration Procedures

The step-by-step calibration procedures for the instruments shall be detailed out for eachindividual instrument in the system. A set of validation check sheets shall also be includedand all readings obtained during each calibration shall be recorded on the check sheets.Adjustment shall be made when a reading is out of tolerance. After any adjustment thecomplete test shall be repeated.

5.3.1.3 Frequency of Calibration and Inspection

Contractor shall detail out the frequency of validation/calibration of each of the meteringinstruments.

5.3.1.4 Flow Calculation

Calculations/formulae used to arrive at the volumetric, mass and heat throughput shall beclearly laid out. All flow constants that are to be used shall be shown in actual units they areused. Where the flow constants are fixed, the actual values and their derivations shall beshown.

5.3.1.5 Metering Irregularity Calculation

All types of irregularities on the metering system and methods for the corrections shall beclearly stated.

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5.3.1.6 Calibration/Validation equipment

A list of the calibration/validation equipment to be used in the validation exercise shall beprovided in the validation manual. All information related to the equipment specificationsuch as its accuracy, repeatability, serial no., and range shall also be provided.

The accuracy of the calibration equipment shall be better than the accuracy of theinstrument to be validated.

The equipment shall be traceable to any National Standard or National Bureau of standardacceptable to the National Standard body.

5.3.1.7 System Uncertainty Calculation

System uncertainty calculation shall be listed in the validation man ual and shall be inaccordance with ISO 5168 latest revision.

5.4 SYSTEM MAINTENANCE

The metering system shall be maintained in order to maintain its accuracy and integrity.

The host country authority approval shall be secured before any change or modification ismade on the metering system. Drawing(s) and sufficient data shall be submitted togetherwith the request for approval.

The host country authority representative(s) shall be invited to witness the maintenanceactivities on the system modification. All results pertaining to these activities shall then beproperly documented. The contractor shall also obtain the vendors recommendedcomprehensive spare parts list and priced quotation for parts commissioning and two yearsoperation.

5.5 SECURITY

All software and all flow factors, status and alarm information stored in the system shall beprotected to prevent loss of information by inadvertent operator action or input powerfa