p muralidharan - kuwaitmeasurement.comkuwaitmeasurement.com/papers/session1/01.pdf · saturated dp...
TRANSCRIPT
P MURALIDHARAN General Manager Swinton Technology Middle East
• Working with Swinton Technology for the past 1 year and responsible for overall Middle East Business
• Total 34 years experience in Process Control Industry of which 22 years experience in Middle East, handling Custody Transfer Flow Products (Orifice, Turbine, PD, Ultrasonic, Coriolis), Flow Computers & Metering Systems
• Bachelor of Technology in Electronics Engg
Orifice Meter Diagnostics
– ConocoPhillips Field Tests
P Muralidharan General Manager
Swinton Technology Middle East
(Richard Steven, DP Diagnostics LLC)
Agenda
• Introduction
• Field Tests-Conoco Phillips
• Conclusions
• Questions and Answers
Introduction
• Orifice flow meters are popular as they are simple, generally inexpensive & reliable
• Current practice of accuracy validation is by routine scheduled inspections
• A diagnostic system (CBM) is desirable as it:
– Guarantees performance therefore reducing exposure to measurement error
– Avoids risky routine inspection – Provides Alerts & identifies problems
flow
P2 P1
DPt
H L
‘Traditional’ Meter
DP (P1-P2)
3 of 40
DP Diagnostic Method
flow
P2 P3 P1
DPt DPr
H L H L
‘Traditional’ Meter
DP (P1-P2) ‘Recovered’ DP
(P3-P2)
3 of 40
DP Diagnostic Method
flow
P2 P3 P1
DPt DPr DPppl
H L H L H L
‘Traditional’ Meter
DP (P1-P2)
‘Recovered’ DP
(P3-P2)
Permanent
Pressure Loss DP
(P1-P3)
3 of 40
Four pairs of ‘normalised’ diagnostic results
plotted as 4 points inside a ‘Normalised
Diagnostic Box’ (NDB).
All points inside the box indicates good meter
performance (each result is within allowable
uncertainty).
10
Simple visualisation
Any point outside of the box means that actual meter
performance is not agreeing with expected and there is
potentially a non-compliance or a fault producing an error
in meter flow rate prediction.
Pattern of diagnostic results provides indication of cause of alarm.
11
Simple visualisation
12
Issues Detected Include:
An Orifice Plate Installed Backwards
A Worn or Damage Orifice Leading Edge
Incorrectly Spanned DP Transmitter.
Orifice Blockage
Meter Incorrectly Installed
Incorrect Inlet or Throat Diameter In Use
Two-Phase Flow
Excessive Upstream Disturbance
Contamination Build-Up
Blocked Impulse Lines
Saturated DP Transmitter
Drifting DP Transmitter
A Buckled Orifice Plate
Agenda
• Introduction
• Field Tests-Conoco Phillips
• Conclusions
• Questions and Answers
ConocoPhillips Field Tests
• ConocoPhillips (CoP) has field tested ‘Prognosis’ on a
live 10” orifice meter at the Franklin gas station in Texas,
USA
• CoP deliberately induced known controlled problems to
test and verify the diagnostic system. The response of
Prognosis to the correctly operating orifice meter is
shown before the response of Prognosis to the various
induced problems are presented.
• Baseline (10”, 0.46 beta, dry gas orifice) ConocoPhillips Field Tests
Measurement error of between -15% and -20%!!
• Backwards installed plate
• Leaking 5-way manifold (DP reading error)
Actual DP 64.57 inH20
DPt drifts -5.4%, DPt read 61.08 inH20
Flow Error -2.7%
• Blocked impulse line (upstream)
Pressure at P1 is ‘stuck’, 2 DPs are affected and hence all
results are affected.
No doubt that there exists a DP integrity issue!!
• Incorrect Orifice Diameter Keypad Entry
-11% bias in flow rate prediction
Actual d = 4.5”
Keypad entered d = 4.25”
• Incorrect inlet diameter keypad entry
<+1% bias in flow rate prediction
Actual ID = 9.75” (schedule 80)
Keypad entered ID = 9.562” (wrong schedule)
Agenda
• Introduction
• Field Tests-Conoco Phillips
• Conclusions
• Questions and Answers
Conclusions
• Swinton Technology & DP Diagnostics have developed and proven an Orifice Meter diagnostic tool called “Prognosis”
• Prognosis can
– Assure correct Orifice Meter Operation
– Reduce exposure to mis-measurements
– Increase productivity of field technicians by reducing inspection visits
Conclusions
• Prognosis has been field tested at
– BP CATS,
– CoP TGT and Franklyn
– Rosneft Polar Lights Field ( Russia)
• Prognosis is procured by
BP, Conoco Phillips, Petronas, Yanpet ( Exxon/Saudi Aramco) , MaerskOil,
Encana, UK National Grid Talisman
• Concept is now included in
– UK governments DECC “ Guidelines for Petroleum Measurement
– The Canadian regulators “ Directive 17”
– QP Measurement Guidelines
