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KOC EXPORT TECHNICAL SERVICES TEAM
LOSS CONTROL SECTION
RTD Drifting in Petroleum Metering Applications at KOC
KHALID SUWAIDAN
• Graduated from Arab Academy for science and technology and the Marine Engineering.
• Joined Kuwait Oil Company in July 2006. Since April 2009, assigned as Loss Control Engineer under Export Technical Services Team.
• Involved and Consolidated experience in:
• Crude oil volume determination • Automatic Tank Gauging (ATG) • Turbine flow meter operations • Positive Displacement flow meter • RTD, Pressure gauge & Prover Calibration, including
Density, Water & Sediment % Lab Analysis Test.
KHALID SUWAIDAN (Snr. Loss Control Engineer)
KOC
Outline:
• Introduction.
• Upgrade.
• The case.
• Solving.
• Result.
• Conclusion.
Introduction:
• There are several element affecting the determination of crude oil volume, such as temperature and pressure, amongst others. Temperature is one of the most sensitive factor considered in the formulation used to calculate Petroleum quantities at base condition, better known as Gross Standard Volume (GSV).
• RTD’s (Resistance Temperature Detectors) are sensing elements with an electrical resistance that is a function of temperature. The temperature detector is usually a small coil of platinum wire that when used with appropriate circuits, will provide accurate and stable temperature signals.
• RTDs are more accurate and maintain their accuracy for long periods than all other temperature sensors. RTDs are recommended for highly accurate temperature measurement such as Custody Transfer applications.
Upgrade: In 2012, flow computers in existing KOC Export metering skids system were upgraded to make them compatible to the new technology available in the market. After commissioning and implementing the new technology, statistical analysis of the operational data obtained reported an issue related to RTD’s Drifting
RTD
Flow Computer
300 mts
Ohm Ω
Old System
Panel Transmitter
4-20 mA
The Issue: Recorded huge differences exceeding the KOC & DIN IEC-751 allowed tolerance (0.18oF) between the temperature measured at the meter skid versus the values reported by the reference standard temperature calibrator.
Jofra Set Temp. Element ΔT* “A” ΔT** “B” ΔT** Status
50 0.51 0.40 0.4 FAIL 70 0.56 0.43 0.36 FAIL 90 0.81 0.43 0.27 FAIL
110 0.79 0.47 0.22 FAIL 130 0.77 0.50 0.19 FAIL
-0.90
-0.60
-0.30
0.00
0.30
0.60
0.90
50 70 90 110 130
Element ΔT* “A” ΔT** “B” ΔT**
Solutions Implemented:
RTD Flow Computer
Ohm Ω
Panel Transmitter
Field Transmitter
4-20 mA 4-20 mA
New System
Results Obtained:
Jofra Set Temp. Element ΔT* "A" ΔT** "B" ΔT** Status
50 -0.08 0.01 0 PASS 70 -0.06 -0.01 0 PASS 90 -0.03 -0.02 -0.01 PASS
110 -0.04 -0.02 -0.01 PASS 130 -0.07 -0.04 -0.03 PASS
-0.90
-0.60
-0.30
0.00
0.30
0.60
0.90
50 70 90 110 130
Element ΔT* "A" ΔT** "B" ΔT**
Before Today32 50
77 70
122 90
167 110
212 130
212 130
167 110
122 90
77 70
32 50
Calibration Scale
Conclusions: • Cable resistance distance affects panel transmitter accuracy.
• Field transmitter provides better accuracy and reliability for RTD. • Minimizing calibration range to our operational range, reduces the
number of RTD trimming • Improvement of the Volume Correction Factor (VCF) determination
Thank You
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