Queensland Gas Pipeline Measurement Manual

Transcription

1

2 Queensland Gas Pipeline Measurement Manual Distribution List The is a controlled document with the Master Copy maintained in the Enterprise Content Management System (ECMS). Electronic Distribution and notification to AAM Operations personal impacted by this Manual is via and includes a link to the document in the ECMS. The document is uncontrolled when printed. HARD COPY DISTRIBUTION Copy Number Location of Hard Copy 1 (MASTER COPY) Technical Library 2 Control Centre Manager, 3 Control Centre 4 QGP Pipeline Marketing Manager 5 QGP ( Gladstone ) Library ELECTRONIC DISTRIBUTION Via ECMS QGP Field Manager Via ECMS QGP Technicians Via ECMS Engineering Manager, Via ECMS Manager Via ECMS Asset Manager Metering Summary of Revisions: Rev. 8 Rev. 7 REV. 6 General reviewing and formatting 1. The requirement to manage calibration gas bottles. 2. Management of Validation activities if not performed on time. 3. HART protocol is the referred digital protocol. 1. Statements of compliance of the Jemena measurement equipment with the requirements of National Greenhouse and Energy Reporting (Measurement) Determination 2008 included. 2. Reference to the Jemena document GTS-001-JJ-004 Uncertainty Calculations for Gas Measurement added with regard to the measurement uncertainties in the Jemena gas custody transfer scheme. 3. Requirements for calibration of the validation equipment added. 4. The appendixes, i.e. the general validation procedures and validation report example deleted, a re-drafted set of general validation procedures added. 5. Added a section on fuel gas measurement. Rev 8 Page 2 of 67.doc

3 Table of Contents 1 SCOPE AND GENERAL Scope Application Terminology & Definitions Terminology Definitions Reference Documents GAS VOLUME MEASUREMENT General and Overview Meter Assembly Orifice Meters Turbine Meters Coriolis Meters Ultrasonic Meters Transmitters, Sensors and RTD s Static Pressure Transmitter Resistance Temperature Detectors (RTD) and Temperature Transmitters Multi-Variable Sensors (MVS) Automitter Flow Computers Computation of Corrected Gas Volumes and Energy Measurement Uncertainties GAS QUALITY MEASUREMENT General Specifications Natural Gas Specification On Site Analysis Chromatographs Moisture Analyser Off Specification Gas METER CALIBRATION FUEL GAS MEASUREMENT Fuel Gas Measurement with Coriolis Meters Fuel Gas Metering with Diaphragm Meters VALIDATION Validation Summary Validation Overview Commissioning and First Yearly Validations Continual Periodic Validations Owners and Representatives Responsibilities Frequency of Validations Validation Spreadsheet Val 1 Test Equipment Val 2 Differential pressure Transmitter Val 3 Pressure Transmitter Val 4 Temperature Transmitter Val 5 Orifice plate FC V s GOF Val 6 Gas Chromatograph Tolerance Check Val 7 Moisture Analyser Tolerance Check Val 8 Pressure Check Run Val 9 Turbine Meter FC V s GOF Val 10 Coriolis Meter FC Check Val 13 Meter Comparison Rev 8 Page 3 of 67.doc

4 Queensland Gas Pipeline Measurement Manual Val 14 Ultrasonic Diagnostic Check Val 15 Ultrasonic Meter FC V s GOF Val 16 Data Transfer Check Calibration of the Validation Equipment REFERENCE AND LOCAL CONDITIONS Validation Spreadsheet Local Conditions Local Gravitational Acceleration Local Atmospheric Pressure Gas Viscosity APPENDIX A GENERAL PROCEDURE FOR VALIDATION OF ORIFICE PLATE FLOW METERS APPENDIX B - GENERAL PROCEDURE FOR VALIDATION OF TURBINE FLOW METERS APPENDIX C GENERAL PROCEDURE FOR VALIDATION OF CORIOLIS FLOW METERS APPENDIX D GENERAL PROCEDURE FOR VALIDATION OF ULTRASONIC METERS APPENDIX E GENERAL PROCEDURE FOR VALIDATION OF PRESSURE TRANSMITTERS APPENDIX F GENERAL PROCEDURE FOR VALIDATION OF TEMPERATURE TRANSMITTERS APPENDIX G GENERAL PROCEDURE FOR VALIDATION OF GAS CHROMATOGRAPHS APPENDIX H GENERAL PROCEDURE FOR VALIDATION OF MOISTURE ANALYSERS Rev 8 Page 4 of 67.doc

5 1 SCOPE AND GENERAL 1.1 Scope This manual is designed to provide a technical reference for the operation and maintenance of the gas measurement and monitoring systems on the Queensland Gas Pipeline. The manual includes general detail of the overall measurement system and equipment, as well as the philosophies used to develop the site specific Standard Operating Procedures (SOP s) for: Validation and calibration of measurement equipment. Analysis of validation data. Adjustment of measured flow quantity. Other aspects of the measurement process, such as billing procedures, system auditing, and billing adjustments are covered under separate procedures as part of the function of the GT Control. This manual is not intended to provide specific details of Gas Sales Contract terms and conditions. 1.2 Application The scope of the manual applies to all Jemena operated custody transfer and check metering facilities on the Queensland Gas Pipeline extending from the receipt/delivery facility at Wallumbilla to delivery facilities in Gladstone and Rockhampton. Figure 1 and Figure 2 provide an overview of the measurement facilities currently maintained on the Queensland Gas Pipeline. Inspection and testing of both the fiscal and non fiscal measurement equipment is addressed in this manual. For the field operations refer to Jemena standard operating procedures. The inspection and testing procedures for independently owned and operated measurement facilities on the Queensland Gas Pipeline are not addressed in this manual. Jemena may, at its sole discretion, approve alternate ownership arrangements for measurement equipment however; such equipment shall conform to the same standards as if Jemena were the operator or as otherwise agreed. Rev 8 Page 5 of 67.doc

6 Figure 1: Queensland Gas Pipeline Facility Overview Map Rev 8 Page 6 of 67.doc

7 Location Wallumbilla Santos Wallumbilla AGL (APA) Wallumbilla EPIC Gooimbah Status Meter Assem bly Not in use Not in use in use Note 2 Meter Runs Pipe Dia. mm Flow Com puter Temp. Trans ducer Press. Trans ducer MSV dp SCA & dp Trans DA Trans ducer ducer Gas Moisture Gas Samp Analyser Chroma ler tograph Orifice Single X X Orifice Single X X X Ultrason Single N/A X X X X Ultrason Dual N/A X X X X Fairview Westgrove Rollestone In use In use in use Orifice Single X X Orifice Single X X Orifice Single X X Rollestone Compr. St. Banana Compr. St. Gladstone City Gate Non Fiscal Non Fiscal Non Fiscal Ultrason Coriolis Ultrason Coriolis Orifice Dual X X QAL Note 1 Ultrason Dual N/A X X X X X BSL Boyne Larcom Creek Rockhampton City Gate Note 1 Turbine Single N/A X X X X X Note 1 Non Fiscal Note 1 Non Fiscal Orifice Single X X X X Orifice Dual X X X X QMAG Note 1 Turbine Single N/A X X X X X ORICA Note 1 Turbine Single N/A X X X X X Note 2 Rotary Single N/A X X X X X X Gladstone Breslin Str Rockhampton North Rockhampton South Note 2 Turbine Dual Series N/A X X X X X Note 2 Turbine Single N/A X X X X X Moura In use Coriolis Single N/A X X Wide Bay In use Orifice Single X X X X Yarwun In use Ultrason Dual N/A X X X X QER In use Orifice Single X X X X TICOR In use Coriolis Single N/A X X X X X X X AMC Not in use Orifice Single X X X X Table 1: Queensland Gas Pipeline Metering Facilities Note 1: These sites have live gas component downloaded to flow computers via SCADA Note 2: The metering facility not owned and not validated by Jemena Rev 8 Page 7 of 67.doc

8 1.3 Terminology & Definitions TERMINOLOGY Unless otherwise stated, all units and terminology used are in accordance with: Australian Standard AS ISO The International System of Units (The SI System) and Its Application and regulations thereunder Commonwealth Weights and Measures (National Standards) Amendment Act 2013 including Regulations Australian Gas Association publication Metric Units and Conversion Factors for use in the Australian Gas Industry To ensure the technical integrity of various standards and software sourced internationally, conversion factors commonly used and accepted in the Australian gas pipeline industry are used DEFINITIONS AGA 3 AGA 7 AGA 8 AGA 9 AGA 11 AMC Billing Period BSL Calibration Calibration Gas Contract(s) ControlWave American Gas Association Report No 3, Orifice metering of natural gas and fluids measurement. Part 3, natural gas applications ANSI / API 2530 August 1992, together with all appendices thereto. American Gas Association Transmission Measurement Committee Report No. 7 Measurement of Gas by Turbine Meters Second Revision April1996 together with all appendices thereto. American Gas Association report No 8 for calculation of super compressibility of natural gas Second Edition November 2003 American Gas Association Transmission Measurement Committee Report No. 9 Measurement of Gas by Multipath Ultrasonic Meter Second Edition April 2007 American Gas Association Transmission Measurement Committee Report No. 7 Measurement of Gas by Coriolis Meter October 2003 Australia Magnesium Corporation The period from 0800 hours on the first day of each month to 0800 hours on the first day of the following calendar month Boyne Smelters Limited To determine the accuracy of a measurement instrument The gas used by a Gas Chromatograph to calibrate against known mole percentage values The various agreements for the purchase and transport of gas via the Queensland Gas Pipeline An Emerson Process Remote Terminal Unit used as an electronic platform for the pipeline facilities control systems Rev 8 Page 8 of 67.doc

9 Control GT Control Custody Transfer Delivered Delivery Point Elliot Energy Energy Accounting Gas Gas Used Gigajoule (GJ) Gladstone City Gate Station GPA 2172 Gross Heating Value(GHV) A function of Jemena in monitoring the Pipeline via the SCADA system and in executing the necessary actions and directives to ensure the effective receipt, transportation and delivery of gas to the Purchasers. The place where gas transmission control occurs. The transfer of responsibility for the care and keeping of the gas. Gas having left the pipeline at the delivery point/s specified in the relevant contract as the point of transfer of custody of the gas from Jemena to the relevant shipper. A defined location for gas to leave the pipeline Flow computer receives data from the pressure, D.P and temperature transmitter. Also receives Gas chromatograph data to calculate flow rates. The volume of gas in standard cubic metres multiplied by the Gross Heating Value (GHV). Standard units are Gigajoules (GJ). The determination of all quantities of gas added to or subtracted from and remaining in the Jemena Pipeline system each billing period and the determination of the energy content of all such quantities of gas. Any naturally occurring mixture of one or more hydrocarbons in a gaseous state, and zero or more of the gases hydrogen sulphide, nitrogen, helium and carbon dioxide, and the residue gas resulting from the treating or processing of the natural gas. Amount of gas calculated by Jemena to have been consumed by Jemena in normal pipeline operations such as fuel for heaters, venting and instrument gas consumption, and will include compressor fuel in later years Joules The facility, constructed by the pipeline owner at the termination of the main section of the pipeline outside the City of Gladstone. Gas Processors Association Standard (or subsequent revisions), and is the method used to calculate Gross Heating Value, Specific Gravity and Super compressibility of natural gas mixtures from compositional analysis. Higher Heating Value (HHV) shall mean the energy produced by the complete combustion of one cubic metre of gas with air, at a temperature of 15 degrees Celsius and at an absolute pressure of kpa, with the gas free of all water vapour, and the products of combustion cooled to 15 degrees Celsius, the water vapour formed by combustion condensed to the liquid state, expressed in MJ per standard cubic meter (MJ/scm). Rev 8 Page 9 of 67.doc

10 Imbalance Input Quantity ISO 6976 Jemena Owned Gas Joule Kilopascal(kPa) Exists in relation to an agreement if there is a difference on any day between the quantities of gas received by the access provider at a receipt point/s for a facility user s account and the quantities of gas delivered to or on account of the facility user at the delivery point/s. The total of all gas received into the pipeline for a given billing period, as measured by the inlet meters. Natural Gas calculation of Calorific values, density, relative density, and wobbe index from Composition. The quantity (in GJ) of gas in the pipeline equal to the difference between linepack and imbalance. The energy expended or the work done when a force of one Newton moves the point of application a distance of one metre in the direction of that force. One thousand pascals and is by definition a measure of absolute pressure. It is sometimes convenient for instrument calibration to use the term kilopascal gauge (kpag). This means that the gauge reads zero at atmospheric pressure. Linepack Measurement Authority Measuring Equipment Megajoule(MJ) Month Moura Seamgas NX 19 Off-specification Gas Orica Origin Output Quantity Petajoule(PJ) The calculated quantity of gas contained in the pipeline at a given point in time (which is necessary for physical operation of the pipeline, excluding System use gas). The Pipeline Owner Includes but is not limited to the pipeline owner s meters, temperature and pressure transmitters, flow computers and gas chromatographs Joules A period extending from the beginning of the first day in a calendar month to the beginning of the first day in the next calendar month. Moura Coal Seam Methane Operations The PAR Project NX 19 to research the Extension of Range of Supercompressibility Tables and developed equations. Gas other than Sales Specification Gas Orica Australia Operations Pty Ltd. Origin Energy The total amount of gas delivered by the pipeline in a given period as measured by the meters at pipeline outlet locations joules Pipeline The pipeline licensed under Pipeline Licence No. 30 pursuant to the Petroleum Act Rev 8 Page 10 of 67.doc

11 Pipeline Controller Pipeline Inlet Pipeline Outlet Pipeline Owner QAL Q-Mag Quantity Queensland Gas Regulations Received Reconciliation Sales Specification Gas Santos SCADA Shipper Specific Gravity Speed of Sound Standard Cubic Metre of Gas An employee of Jemena working at the Pipeline Control Centre in Melbourne The location(s) at which gas enters the pipeline, specified in the relevant contract as the point of transfer of custody of the gas from the relevant supplier to the shipper and simultaneously and instantaneously from the shipper to the pipeline owner. The location at which gas leaves the pipeline, specified in the relevant contract as the point of transfer of custody of the gas from the pipeline owner to the shipper. Jemena Queensland Alumina Limited Queensland Magnesium (Operations) Pty Ltd The quantity of gas measured in terms of its energy content. Includes Gas Supply Act 2003, Petroleum and Gas (Production and Safety) Act 2004, National Gas (Queensland) Act 2008, Energy and Water Ombudsman Act Gas having entered the pipeline at the inlet receipt point specified in the relevant contract as the point of custody transfer from the supplier to the shipper. The process through which Jemena conducts an energy balance at the end of each billing period, and allocates any metering discrepancies in an agreed manner. Gas, which meets all of the agreed requirements for content and properties as set out in Table 1. The company operating the Coal bed methane field located at Fairview near Injune Supervisory Control and Data Acquisition and refers to the electronic means of receiving remote data and of sending remote control signals and data to pipeline facilities from the Melbourne Control Centre. An entity receiving transportation service on the pipeline pursuant to an effective Transportation Service Agreement (also known as the facility user or, in certain circumstances, access provider under the Pipeline Access Principles). The density of dry gas divided by the density of dry air, both at 15 C and at a pressure of kpa. The speed of sound for a particular gas composition The unit of volume of gas free from water vapour, which would occupy a volume of one (1) cubic metre at a temperature of 15 Celsius and an absolute pressure of kilopascals. Rev 8 Page 11 of 67.doc

12 Standard Measurement Conditions Straightening vanes Suncor Supercompressibility Supplier System Use Gas Terajoule(TJ) Ticor Validation or "Verification Wobbe Index Defined as kpa and 15 Celsius Tubes found upstream of the metering device to induce laminar flow The operating company of the Suncor Oil Shale Project A factor expressing a deviation of a gas from perfect gas laws The party contracted by a shipper to supply gas at any of the pipeline inlets for transport in the Queensland Gas Pipeline The quantity of gas used in the operation of the pipeline, including, fuel gas and lost or unaccounted for gas joules Ticor Chemical Company The process of periodically checking and servicing the measurement equipment to ensure that it continues to function within agreed levels of accuracy. The calorific value of the gas on a volumetric basis, at specified reference conditions, divided by the square root of the relative density of the gas at the same specified metering reference conditions REFERENCE DOCUMENTS Measurement Standards: American Gas Association Transmission Measurement Committee Report No. 3 Orifice Metering of Natural Gas Third Edition 1992 Second Printing 2003 American Gas Association Transmission Measurement Committee Report No. 7 Measurement of Gas by Turbine Meters Second Revision1996 American Gas Association Transmission Measurement Committee Report No 8 Compressibility Factors of Natural Gas and Other Related Hydrocarbon Gases Second Edition November 1992 Third printing November American Gas Association Transmission Measurement Committee Report No 9, Rev 8 Page 12 of 67.doc

13 Measurement of Gas by Multipath Ultrasonic Meter Second Edition April 2007 American Gas Association Transmission Measurement Committee Report No 11, Measurement of Gas by Coriolis Meter October Australian Standard Conversion Factors Australian Standard Specification for general purpose natural gas ISO Natural Gas: Calculation of Calorific Values, Density, Relative Density and Wobbe index from composition. 2 GAS VOLUME MEASUREMENT 2.1 General and Overview Jemena is the Measurement Authority for the Queensland Gas Pipeline (QGP) with responsibility for measurement and reconciliation of gas received and delivered on the QGP. Generally, Jemena owns, operates and maintains flow and gas quality measuring equipment at Receipt and Delivery Points on the pipeline. Check metering facilities are located at strategic positions upstream of the Rockhampton and Gladstone markets to measure the co-mingled quality and quantity of gas prior to delivery. Flow measurement facilities are maintained by Jemena at each Delivery Point, except at Origin Energy locations, which are maintained by Origin Energy. Where Delivery or Receipt Point measurement equipment is owned or operated by a 3rd party, they will be maintained in accordance with this manual and Jemena requirements or as otherwise agreed. Monitoring of flow is achieved using the SCADA system. Land, satellite and on radio communications link the Melbourne Control Centre to on site measurement equipment at each receipt, check and key delivery points. Measured flow is corrected for temperature and pressure to produce instantaneous volumetric and energy based flow rates at standard conditions and gas composition in the on-site flow computer. The on-site flow computer maintains an accumulated record of volume and energy passing through the meter. In conjunction with line pack calculations, the accumulated quantities are used for the daily reconciliation and balancing of the pipeline. Those Delivery Points not scanned by the SCADA system are checked daily, with accumulator data forwarded to the Melbourne Control Centre. Shipper delivery points have either Ultrasonic, Orifice, Coriolis or Turbine metering systems, which include compensation of energy flow for temperature and pressure. The equipment specification varies between measurement facilities, however the schematic shown below identifies and links the key repeated components. Rev 8 Page 13 of 67.doc

14 Meter Assembly Temperature Sensor Pressure Sensor Gas Chromatograph Flow Data Static Temperature Static Pressure Gas Quality Gas Quality Flow Computer Instantaneous: -mass flow -volumetric flow -std. volumetric flow - energy flow -temperature -pressure -gas quality Totalised: -mass flow -volumetric flow -std. volumetric flow - energy flow Local Display Local Printer SCADA Meter Tube Figure 3: Measurement Facility Schematic 2.2 Meter Assembly The meter assembly measures dynamic flow properties for use in the calculation of volumetric and energy flow. Four styles of meter assembly are in service on the pipeline. Jemena receipt and check stations use orifice, ultrasonic and coriolis type meters. At the Delivery Points, a mixture of orifice, ultrasonic, and rotary meters are employed ORIFICE METERS The orifice meter most frequently handles the process of measuring large volumes of gas. It consists of an orifice plate to constrict the size of the flow path at a particular point causing the gas to increase velocity in order to pass through the orifice. This subsequently causes a rapid drop in static pressure directly behind the orifice plate that, with the use of pressure differential measuring equipment, allows calculation of the instantaneous flow rate. Straightening vanes are inserted in the upstream section of the meter tube to aid in eliminating the turbulent flow patterns induced by certain features of the upstream piping allowing a concise meter reading as shown in Figure 4. Figure 4: Orifice Meter Schematic Rev 8 Page 14 of 67.doc

15 Orifice meters are installed, operated and maintained as per the requirements of the American Gas Association (AGA) Report No. 3. Orifice plates are removed and checked for recorded dimensional details, flatness, and sharpness of leading edge (in compliance with the manual of petroleum measurement standards CH 14 Section 3). Differential pressure sensing lines are leak tested. Differential pressure transmitters are calibrated across their range. A known differential pressure is applied to the transmitter and the differential pressure reading (kpa) from the flow computer display is compared for accuracy of values. Dual differential pressure transmitters are fitted where analogue signals are used between the transmitters and the flow computers, maximising the acceptable flow range of a given plate. Where the use of digital signals has been implemented, a single DP transmitter is used. Ongoing performance monitoring, guards against the under or over ranging of the meters, with plates changed out to suit short or long term changes to flow conditions Temperature and pressure transmitters are located with each meter and are used to calculate the volumetric flow at Standard Measurement Conditions. Jemena QGP custody transfer gas measurement facilities, equipped with orifice plate type meters, include the following metering stations: 1. Fairview 2. Westgrove 3. Wide Bay 4. QERL The meter facilities are designed and installed in accordance with AGA Transmission Measurement Committee Report No. 3 Orifice Metering of Natural Gas. The typical uncertaintyof the meters is in the range of 0.9%. (Ref. Jemena document GTS-001-JJ- 004 Uncertainty Calculations for Gas Measurement). Consequently, the orifice plate meters, used on QGP, comply with the National Greenhouse and Energy Reporting (Measurement) Determination 2008 Chapter 2, Part 2.3 Division Section TURBINE METERS The turbine meter is generally used where there is a requirement to record smaller more variable flow rates. The turbine meter has a turbine rotor, which rotates as gas passes through it. Permanent magnets attached to the rotor tips turn with the rotor and produce magnetic currents in a coil causing a voltage pulse. Every time a magnet passes the coil a pulse is recorded and the total amount of gas that has gone through the meter is calculated. Straightening vanes are inserted in the upstream section of the meter tube to aid in eliminating the turbulent flow patterns induced by the upstream piping allowing a concise meter reading as shown in Figure 5. Rev 8 Page 15 of 67.doc

16 Figure 5: Turbine Meter Schematic All turbine meters are installed in accordance with AGA 7 and are laboratory calibrated prior to installation. Temperature and pressure transmitters are located with each meter and are used to calculate the volumetric flow at Standard Measurement Conditions. At approximately six-month intervals, the in-service turbine meter is placed in series with another laboratory calibrated meter. The throughput of each meter is measured and recorded. The results of the comparison must be within 1% for continued use of the in-service turbine. The pulse transmitter on the meter is tested using a frequency generator. A calibrated spare meter or spare internals is held in stock to allow replacement of any deteriorating meter. Jemena QGP gas measurement facilities, equipped with turbine type meters, include the following metering stations: 5. Orica 6. Q-Mag 7. Boyne Island Barton 7400 Series Turbine meters, equipped with the Barton 800 series pre-amplifiers are typically used at the facilities. The meters are designed for the custody transfer applications in demanding industrial environment and they are manufactured and tested in accordance with the European Union Pressurised Equipment Directive (PED). The typical uncertainty of the meter is in the range of 1.0% for a single linearity K-factor (Ref. Jemena document GTS-001-JJ-004 Uncertainty Calculations for Gas Measurement). Consequently, the turbine meters, used on QGP, comply with the National Greenhouse and Energy Reporting (Measurement) Determination 2008 Chapter 2, Part 2.3 Division Section CORIOLIS METERS The Coriolis Meter uses an obstruction less U-shaped tube as a sensor. Inside the sensor housing, the sensor tube vibrates at its natural frequency. The sensor tube is driven by an electromagnetic drive coil located at the centre of the bend in the tube and vibrates similar to that of a tuning fork (Figure 6a). Rev 8 Page 16 of 67.doc

17 Figure 6a Figure 6b Figure 6c The fluid flowing into the sensor tube is forced to take on the vertical momentum of the vibrating tube. When the tube is moving upward during half of its vibration cycle the fluid flowing into the sensor resists being forced upward by pushing down on the tube. (Figure 6b) The fluid flowing out of the sensor has an upward momentum from the motion of the tube. As it travels around the tube bend, the fluid resists changes in its vertical motion by pushing up on the tube. The difference in forces causes the sensor tube to twist. When the tube is moving downward during the second half of its vibration cycle, it twists in the opposite direction. This twisting characteristic is called the Coriolis effect. (Figure 6c). The amount of sensor tube twist is directly proportional to the mass flow rate of the fluid. Electromagnetic velocity detectors located on each side of the flow tube measure the velocity of the vibrating tube. Mass flow is determined by measuring the time difference exhibited by the velocity detector signals. During zero flow conditions; no tube twist occurs, resulting in no time difference between the two velocity signals. With flow, a twist occurs with a resulting time difference between the two velocity signals. This time difference is directly proportional to mass flow The Flow Computer receives data from the Meter in terms of pulses/kg and live gas quality data from a gas chromatograph, this enables calculation of gas volume and energy flow rates at standard conditions. The Micromotion ELITE series H Coriolis sensor is used in the Coriolis measurement application on QGP. The sensor is interconnected to the RF9739 or Series 2000 Coriolis transmitter. The uncertainty of the mass flow measurement for the above combination of the equipment is declared by the manufacturer as 0.5 % of rate, although the equipment calibration certificates indicate significantly better performance in the range of %. Following the manufacture s statement the uncertainty for the Coriolis gas custody transfer measurement is assumed to be 0.5% (Ref. Jemena document GTS-599-JJ-004 Uncertainty Calculations for Gas Measurement). Consequently, the Coriolis meters, used on QGP, comply with the National Greenhouse and Energy Reporting (Measurement) Determination 2008 Chapter 2, Part 2.3 Division Section Rev 8 Page 17 of 67.doc

18 2.2.4 ULTRASONIC METERS The Ultrasonic meter measures the difference in time taken for sound waves to travel in the gas stream between up and downstream-paired transducers. Ultrasonic sound pulses are launched in each direction (as shown in Figure 7), their time of transit is measured, and the difference can be related to the speed of flow in the pipe. Ultrasonic meters have several sound wave paths through the gas in the pipe. Algorithms are used to derive the average flow velocity and determine if swirl or turbulence is present. The actual volumetric flow rate is calculated from the average velocity and the internal diameter of the meter. The Flow computer converts the actual volumetric flow rate to volumetric flow rate at Standard Conditions and Energy flow rate using inputs from pressure and temperature sensors and gas quality data. Figure 7: Ultrasonic Meter Schematic Where: D = Diameter of pipe L = Ultrasonic wave path distance A & B = Transducers ϕ = Angle between pipe axis and acoustic path v = Velocity of gas Ultrasonic meters are installed, operated and maintained as per the requirements of the American Gas Association (AGA) Report No. 9, latest edition, and the manufactures installation, operating and maintenance manual. Periodic checks, called validations, are carried out to confirm the accuracy and integrity of the meter set. This includes checks of the Automatic Gain and Level Control, correct ultrasonic pulse rate and velocity of sound. This data indicates if any of the ultrasonic paths are fouled, the meter is subject to external noise or any of the ultrasonic transducers are deteriorating. Monitoring of the measured velocity of sound will show if there is any change in a critical dimension or the reference clock has drifted. Checks and calibration of temperature and pressure transmitters are also carried out during a validation. On-line diagnostics continuously monitor the performance of the meter. These diagnostic checks help to locate any metering discrepancies. Once identified, a discrepancy is investigated by Jemena field staff. Metered data validations will be initiated to prove metering at any site as dictated by the field investigation. Where possible, delivery point meters will be operated in series with a nominated duty meter and stand-by meter. Rev 8 Page 18 of 67.doc

19 Sick Maihak FlowSick600 ultrasonic meters are used on the QGP metering facilities. The measurement uncertainties for these ultrasonic meters do not exceed 0.21% of their measurement range (Ref. Jemena document GTS-011-JJ-004 Uncertainty Calculations for Gas Measurement). Consequently, all ultrasonic meters, used on QGP, comply with the National Greenhouse and Energy Reporting (Measurement) Determination 2008 Chapter 2, Part 2.3 Division Section Transmitters, Sensors and RTD s Transmitters, Sensors and Resistance Temperature Detectors (RTD) are mounted with each meter assembly depending on site requirements. They are used in the calculation of the correction factor which, converts the gross metered flow to a net volume at standard measurement conditions STATIC PRESSURE TRANSMITTER The static pressure transmitter is comprised of a simple diaphragm of which one side is exposed to pressure. The amount of pressure placed on this diaphragm provides a corresponding distortion, which can be measured to give a static pressure reading. The static pressure sensing lines are leak tested and the transmitter is calibrated across its range. The flow computer display pressures are then compared to known test values. Accuracy of the Static pressure sensor and flow computer inputs are checked periodically as part of routine validations The transmitter is calibrated across its range using a Dead Weight Tester (DWT) or an electronic pressure calibrator. A known pressure is applied to the transmitter. The pressure reading (kpa) from the flow computer display is compared to a known value. The DWT and electronic pressure calibrator is regularly bench calibrated at a NATA certified facility. Allowance is made for local gravity, barometric pressure head of oil, and temperature for the DWT. For both the Ultrasonic and Turbine meters, pressure sensors are mounted on each meter assembly. The static pressure is used in the calculation, which converts the actual metered volumetric flow to a volume flow at standard conditions. A pressure sensor is also mounted on the coriolis meters for pressure compensation of the sensor tube The following two brands of pressure transmitters are commonly used on QGP: Honeywell ST 3000 Smart Transmitter - the declared manufacturer s total uncertainty for the transmitter amounts to URL. Rosemount 3051 series Smart Pressure Transmitters the declared base uncertainty of the transmitter measurement is 0.04 URL. Both transmitters have the ability to transfer their sensor reading digitally. However the ST 3000 digital signal is proprietary with limited RTU compatibility. In contrast the open HART protocol found in Rosemount series transmitters has a larger support base. HART communications of pressure transmitter increase metering accuracy by reducing uncertainties introduced by the isolating barriers and RTU A/D modules. For this reason HART communications is the preferred communications protocol for fiscal pressure transmitters. For the purposes of the transmitter validation tolerance calculations the uncertainty of the pressure transmitter measurement is assumed to be 0.1 URL to allow for stability deterioration over time and to set reasonable validation targets (Ref. Jemena document GTS-001-JJ-004 Uncertainty Calculations for Gas Measurement). Rev 8 Page 19 of 67.doc

20 Consequently, all pressure transmitters, used on the Queensland Gas Pipeline Metering sites are compliant with the transmitter accuracy requirements, as defined in the National Greenhouse and Energy Reporting (Measurement) Determination 2008,, refer Chapter 2, Part 2.3 Division Section 2.32, and Chapter 1, Part 1.1A, Division 1.1A.2, Section 1.10F RESISTANCE TEMPERATURE DETECTORS (RTD) AND TEMPERATURE TRANSMITTERS The operating principle of the Resistance temperature detector is relatively simple. A platinum wire is fixed within a probe positioned mid stream in the pipe. The resistivity of a conductor is proportional to its temperature. Hence, variation in gas temperature can be inferred from the variation in the measured resistance across the platinum wire. Flow computers monitor the resistance across the platinum wire and convert it to temperature for use in flow calculations. Accuracy of the RTD and flow computer inputs are checked periodically as part of routine validations of gas analysis and energy accounting equipment. The RTD is performance checked using an ice point generator. The measured resistivity at 0 C. is compared to the expected 100 Ohms. The temperature transmitters are calibrated using a certified resistance device. A known resistance is placed on the input to the transmitter and the expected temperature is compared to that indicated on the flow computer. The following types of the temperature transmitters are commonly used on QGP: Honeywell STT350 Smart Temperature Transmitter - the declared manufacturer s total uncertainty is 0.01 ºC, for the transmitter operating in the DE digital mode and in the range of ºC with Pt100 sensor. For the transmitter operating in analog 4-20 ma mode the uncertainties are in the range of 0.025%, i.e ºC. Rosemount 3144 series Smart Temperature Transmitters the declared base accuracy of the transmitters varies, depending on the variation of the Transmitter/Sensor arrangement, type of the sensor and the signal transmission techniques used. The declared manufacturer s total uncertainty is 0.1 ºC, for the transmitter operating as 4-20 ma in the range of ºC with Pt100 sensor. The manufacturer s declared ambient temperature effect for the transmitter operating with Pt100 in the ºC is ºC Both transmitters have the ability to transfer their sensor reading digitally. However the STT350 digital signal is proprietary with limited RTU compatibility. In contrast the open HART protocol found in Rosemount series transmitters has a larger support base. HART communications of temperature transmitter increase metering accuracy by reducing uncertainties introduced by the isolating barriers and RTU A/D modules. For this reason HART communications is the preferred communications protocol for fiscal temperature transmitters. For the purposes of this Manual the uncertainty of 0.1%, i.e. 0.1 ºC have been conservatively assumed for all temperature transmitters, installed at the pipeline metering facilities (Ref. Jemena document GTS-001-JJ-004 Uncertainty Calculations for Gas Measurement). Consequently, all temperature transmitters, used on Quensland Gas Pipeline Metering sites are compliant with the transmitter and accuracy requirements, as defined in the National Greenhouse and Energy Reporting (Measurement) Determination 2008,, refer Chapter 2, Part 2.3 Division Section 2.32, and Chapter 1, Part 1.1A, Division 1.1A.2, Section 1.10F MULTI-VARIABLE SENSORS (MVS) A multi-variable Sensor is the combination of both a static pressure Sensor and differential pressure Sensor (D.P) in the one unit. The Sensor is made up of two diaphragms, of which the Rev 8 Page 20 of 67.doc

21 distortion under pressure is measured to give a comparative readout. Multi-Variable Sensors also have the added advantage that they are a lot simpler to use during calibration. This is due to that fact that digital data transfer is used instead of the analogue system that requires regular adjustment. Details on where (MVS s) are used on QGP can be found in Table AUTOMITTER The flow Automitter unit is comprised of a Multi-Variable Sensor and an attached RTD forming a complete gas flow measurement interface for one orifice run. The unit provides for static pressure, differential pressure and temperature inputs to the flow computer transferred with a digital signal. 2.4 Flow Computers The flow computer performs three main functions: Computation of volume and energy flow-rate Calculation of flow Accumulation registers. Data transfer Each ultrasonic and turbine meter is connected to a local electronic flow computer, which receives and records the instantaneous values for all primary measurement inputs, i.e. volume flow signals from the meter as well as pressure and temperature information from the transmitters. From these inputs and along with the gas analysis, the flow computer continuously calculates the following: Instantenouos corrected volumetric flow Cumulative corrected volumetric flow Instantenous uncorrected volumetric flow Cumulative uncorrected volumetric flow Supercompressibility factor. Each Coriolis meter is connected to a local electronic flow computer, which receives a mass flow signal from the meter. Volume at standard conditions and energy flow rates through the meter are calculated from this signal and the specific gravity of the gas provided by a gas chromatograph. From these inputs and along with the gas analysis, the flow computer continuously calculates the following: Instantenouos corrected volumetric flow Cumulative corrected volumetric flow Supercompressibility factor All flow computers accumulate volume and energy totals. Each orifice plate meter is connected to a local electronic flow computer, which receives a differential pressure developed across the orifice plate. The pressure drop across the plate is related to the instantaneous flow rate.. It also receives pressure and temperature information from the transmitters. From these inputs and along with the gas quality data, the flow computer continuously calculates the following: Instantenouos corrected volumetric flow Cumulative corrected volumetric flow Instantenous uncorrected volumetric flow Rev 8 Page 21 of 67.doc

22 Cumulative uncorrected volumetric flow Supercompressibility factor All flow computers accumulate volume and energy totals. Consequently, the flow computers, used on QGP, comply with the National Greenhouse and Energy Reporting (Measurement) Determination 2008 Chapter 2, Part 2.3 Division Section All calculations done by the computer are in accordance with recognised industry standards. Gas quality data electronically downloaded to each flow computer includes: - Higher (Gross) Heating Value - Relative Density - Nitrogen Content - Carbon Dioxide Content - Hydrocarbon Components - Meter specific data Inputs manually programmed into the flow computers are: - Site specific Atmospheric Pressure - Contract Base Pressure - Contract Base Temperature SCADA outputs from the computer are: - Pressure - Temperature - Flow Rate - Energy Rate - Accumulated Flow - Accumulated Energy - Specific Gravity - Heating Value - Gas component data - Yesterdays energy - Yesterdays volume - Contract energy accumulator - Contract volume accumulator Flow calculations are carried out as per the AGA standard appropriate to the metering apparatus. Supercompressibility is calculated for the purpose of flow correction as per the requirements of the AGA Report No. 8, second edition Rev 8 Page 22 of 67.doc

23 All functions of the flow computer are checked using electronic test instrumentation. Performing a flow calculation using measured properties substituted into custom software, and comparing the result with that from the flow computer assesses calculation accuracy. Details on Flow computer validation checks can be found in Section H. 2.5 Computation of Corrected Gas Volumes and Energy Calculation of volumetric flow is specific to the metering system being used. In general, however, the meter assembly is measuring the flow. Turbine meters, Coriolis and ultrasonic meters measure the volume/mass of flowing gas directly. Orifice meters infer flow velocity from a measured pressure differential across a fixed restriction in the gas stream. The measured, line flow rate (m3) is corrected to standard conditions (sm3) using a correction factor based on the gas composition and the flow temperature and pressure. The energy based flow rate (GJ/day) used in the daily operation of the pipeline is established by multiplying the calculated standard flow rate (sm3/hr) by the calculated Gross Heating Value (MJ/sm3) of the gas, and adjusting the time scale. 2.6 Measurement Uncertainties The uncertainties in the Jemena custody transfer measurement system have been estimated and the results of the calculations are presented in the GTS-199-RP-004 Calculation of Measurement Uncertainties. The Wholesale Market Metering Uncertainty Limits and Calibration Requirements Procedures document, as produced in accordance with the requirements of the National Gas Rules 2008 (Version 18) where by AEMO (Australian Energy Market Operator), was adopted for the assessment and benchmarking of the performance of the Jemena measurement facilities. On the basis of the calculations, all Jemena custody transfer facilities on Queensland Gas Pipelines can be declared as compliant with the AEMO uncertainty requirements for the volume and energy flow categories. 3 GAS QUALITY MEASUREMENT 3.1 General Gas entering the pipeline must meet certain specifications before it is transmitted through the line. Jemena monitor the gas quality to ensure it meets these specifications 3.2 Specifications The Jemena Standard Terms and Conditions for the QGP state the acceptable gas quality limits that apply to gas to be transported. Those requirements are restated in Table 1 below. Jemena is contractually obligated to flow, on behalf of its Shippers, only gas that meets the specification. It is the Shipper s responsibility to ensure that gas to be transported meets this specification at its Receipt Point(s). Jemena will immediately notify the Shipper and Supplier when gas is not meeting specifications as identified by Jemena gas quality measuring devices at the Receipt Point(s). Steps as outlined in Section 4.13 of the Operations Manual may be taken by Jemena in the event of off-specification gas. However, this action, nor the knowledge of the presence of off-specification gas by Jemena personnel relieve the Shipper from its contractual obligation for providing gas meeting Rev 8 Page 23 of 67.doc

24 specifications, or liability for any consequential damage incurred by Shippers directly or indirectly due to the acceptance of off-specification gas on behalf of a Shipper NATURAL GAS SPECIFICATION This specification requires that the Natural Gas: 1) Be commercially free from sand, dust, gums, gum forming constituents, crude oil, impurities or other objectionable substances; and 2) Have measured or calculated values for certain parameters within the stated tolerances; and 3) Does not cause damage to the Pipeline and associated infrastructure, and does not interfere with: i. The transmission of the Natural Gas through the Pipeline; OR ii. The commercial use of the Natural Gas by you and other Users. Table 2: Requirements for acceptable gas quality ITEM SPECIFICATION STANDARD Minimum Temperature Maximum Temperature 10 C 50 C Wobbe Index Minimum 47.0 Maximum 52.0 Maximum Oxygen 0.2 mol% AS4564 Maximum Inerts (non-combustibles) Hydrocarbon Dewpoint Maximum Water Content Maximum Hydrogen Sulphide Maximum Carbon Dioxide 6 mol% if HV 37.9 MJ/m 3 and 42.3 MJ/m 3 4 mol% if HV 35 MJ/m 3 and 43 MJ/m 3 Maximum 10 10,000 kpag (or maximum 2 3,500kPag) 65 mg/m mg/m 3 AS % by volume Total Sulphur 50 mg/m 3 AS4564 Mercaptan 15 mg/m 3 Gross Heating Value Minimum 35 MJ/m 3 Maximum 43MJ/m 3 NOTES: 1. All values measured or specified at 15 C and kpa unless otherwise stated. Rev 8 Page 24 of 67.doc

25 2. Wobbe Index means the Higher Heating Value divided by the square root of the relative density of the gas, both measured at the same time. 3. For the purposes of this clause, carbon dioxide and nitrogen shall be deemed to be inert gases. 4. For the avoidance of doubt, objectionable substances include.: a) material, dust and other solid or liquid matter, waxes, gums, gum forming constituents, and unsaturated or aromatic hydrocarbons to an extent which might cause damage to, or interfere with the proper operation of pipes, meters, regulators, control systems, equipment or appliances; b) Unsaturated or aromatic hydrocarbons to an extent which causes unacceptable sooting; c) Other substances to the extent that they cause damage to, or problems in the operation of, pipelines or appliances or that cause the products of combustion to be toxic, or hazardous to health, other than substances that are usually found in natural gas combustion products. 5. Oil content shall be less than 20 ml per 1 TJ of gas 3.3 On Site Analysis Gas Chromatographs that sample line gas and separate the inert and hydrocarbon components to C6+ and C9+ are used to analyse the gas stream. Gas composition, specific gravity, heating value and Wobbe Index of the gas are determined. Moisture analysers are used to continuously sample the gas stream to establish its water dew point. RTD probes measure the gas temperature. The table below lists the properties measured and calculated from the on-site analysis. Table 3: Output from on-site analysis MEASURED ON-LINE Hydrocarbon breakdown to C6+ Hydrocarbon breakdown to C9+ Carbon Dioxide Nitrogen Moisture Dew Point Gas Temperature CALCULATED ON-LINE Higher Heating Value Specific Gravity Wobbie Index Hydrocarbon Dew Point Live monitoring of the gas quality is enabled via the SCADA system. Output from the on-site measurement equipment is linked to the Central Pipeline Control Centre. Alarms are triggered should the measured or calculated gas properties approach the limits specified CHROMATOGRAPHS A small gas sample is retrieved from the pipeline at nominal intervals of 3 6 minutes. The sample is separated into its basic components and is analyzed by the C6+ gas chromatograph, returning the following: - Hexane Plus (C6+) Rev 8 Page 25 of 67.doc

26 - Propane (C3) - I-Butane (I-C4) - N-Butane (N-C4) - Neo-Pentane (Neo-C5) - I-Pentane (I-C5) - N-Pentane (N-C5) - Nitrogen (N2) - Methane (C1) - Carbon Dioxide (CO2) - Ethane (C2) The C9+ chromatograph system analyses for the following components: - Hexane (C6) - Propane (C3) - I-Butane (I-C4) - N-Butane (N-C4) - Neo-Pentane (Neo-C5) - I-Pentane (I-C5) - N-Pentane (N-C5) - Nitrogen (N2) - Methane (C1) - Carbon Dioxide (CO2) - Ethane (C2) - Nonane+ (C9) - Octanes (C8) - Heptanes (C7) Rev 8 Page 26 of 67.doc