© 2019 Department of Petroleum Resources. All rights reserved Department of Petroleum Resources (DPR) PROCEDURE GUIDE

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1.13 Factory Calibration ................................................................................................ 85 
1.13.1 Flow Computer Calculations .............................................................................. 85 
1.15 MEASUREMENT OF GAS BY MULTIPATH ULTRASONIC METERS .......................... 86 
1.15.1 Introduction ....................................................................................................... 86 
1.15.2 Design requirements:......................................................................................... 86 
1.15.3 Gas quality ......................................................................................................... 87 
1.15.4 Pressure ............................................................................................................. 87 
1.15.5 Temperature ...................................................................................................... 87 
1.15.6 Meter performance requirement ...................................................................... 87 
1.15.7 Meter accuracy .................................................................................................. 87 
1.15.8 ULTRASONIC METER INSTALLATION REQUIREMENT ........................................ 88 
1.15.8.1 Pressure taps ................................................................................................... 88 
1.15.8.2 Piping installation ........................................................................................... 88 
1.15.8.3 Protrusions ...................................................................................................... 88 
1.15.8.4 Meter body length and bores ......................................................................... 88 
1.15.8.5 Thermowells ................................................................................................... 88 
1.15.8 Environmental consideration ............................................................................ 88 
1.15.9 Associated flow computer ................................................................................. 89 
1.15.10 Density measurement ...................................................................................... 89 
1.15.11 Orientation of Meters ...................................................................................... 89 
1.15.12 Meter Tube Inspection and Cleaning Ports ..................................................... 89 
1.15.13 Flow conditioner .............................................................................................. 89 
1.15.14 Flow Computer Calculations ............................................................................ 89 
1.15.15 Field Meter validation ...................................................................................... 90 
1.15.16 Pre-commissioning checklist ............................................................................ 90 
1.16 LNG OPERATIONS .................................................................................................. 91 
1.16.1 QUALITY OF LNG FOR TRUCKING IN NIGERIA .................................................... 91 
1.16.2 CERTIFICATE OF QUANTITY ................................................................................ 92