Managing Measurement Uncertainty. David Fisher Emerson Process Management

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3 Managing Measurement Uncertainty David Fisher Emerson Process Management

4 DAVID FISHER Flow Solutions Advisor EMERSON PROCESS MANAGEMENT Over 25 years experience spanning all aspects of measurement in the hydrocarbon supply chain including the design, testing, consulting & auditing. I am a Chartered Engineer with the Engineering Council and a member of the Institute of Measurement and Control.

5 MANAGING MEASUREMENT UNCERTAINTY without the MATH

6 Are We Measuring Accurately and Are We Seen to be Measuring Accurately! When a measurement is made there are two important values associated with the result of the measurement process. The first is the numerical value of the variable being measured, The second is the uncertainty associated with that numerical value.

7 Error Error is the difference between the true value of the measurand and the measured value. The total error is a combination of both systematic error and random error. Precision & Accuracy Precision is the closeness of agreement between independent measurements, largely affected by random error. Accuracy is an expression of the lack of error. Uncertainty Uncertainty characterizes the range of values within which the true value is asserted to lie with some level of confidence. Metering Codes, Best Practices & Standards Metering Calibration, Auditing & Validation Measurement Uncertainty by Statistical Evaluation of Errors

8 Measurement System Uncertainty Is decomposed according to various error sources, e.g. belonging to different stages of the measurement procedure, measurement equipment, performance, conditions of measurement or the measurement object itself. Our Engineering approach is simple, clear and widely applied Emerson Established In-house Uncertainty models for all technologies are developed as transparent and traceable incl. design, operation and maintenance effects Primarily based on principles in ISO5168 Referencing ISO/IEC Guide 98:1993 Guide to the expression of uncertainty in measurement (GUM)

9 Spurious Errors result from obvious failures, in the sense that they can be identified and documented. Remedy: Good procedures Random Errors cause a variation in the output reading even when the input parameter has not changed. Remedy: Track Repeatability and Define an Uncertainty Tolerance Constant Systematic Errors also called the bias, may vary over the range but is constant and can be corrected out of the reading. Remedy: In-situ proving of the meter & verification process Variable Systematic Errors slowly vary over time in a constant direction, caused by wear, fatigue, erosion etc. Remedy: Regular proving of the meter, Verification and Good Maintenance

10 Flow Distortion Faulty system design, excessive flow. Remedy: Good Design Consultation Contamination & Phase Change Wax, lube oil, soot, gas break out or liquid drop out.. Remedy: Good Condition Based Monitoring, Equipment Selection Installation Effects Flow Profile, damage or debris, operating conditions... Remedy: Good Design Operation Operating equipment outside design parameters, accepting Meter Factors. Remedy: Good Diagnostics Maintenance Poor maintenance of primary, secondary and qualitative instruments.. Remedy: Good procedures

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12 ORIFICE

13 The Waterdraw The Prover Indicated volume of the meter at Operating Pressures and Temperatures : GROSS Compositional analyses used to make corrections in the quality and/or quantity of the indicated volume : NET Provides the same unbiased answer from the same data, regardless of whom or what does the computing. NET BS&W Level 5 : Meter Indicated Volume Uncertainty : 0.10% Level 6 : Corrected Quality & Quantity Uncertainty : 0.15% Level 7 : Custody Transfer Ticket Uncertainty : 0.20% The Meter The System

14 Countries Oil Production per day Million barrel s Nominal Commercial Export Sell Price (2015) - $50 per barrel Measurement Uncertainty Oil Volume (Barrel s per DAY) Financial Exposure Per YEAR! (+/-) 0.15% 2,000 $73.00 million 0.25% 3,400 $ million 0.50% 6,750 $ million 1.00% 13,500 $ million 2.00% 27,000 $ million 5.00% 67,500 $2, million

15 FLOW SOLUTIONS CONSULTING ADVISORS Guidance, Problem Solving, Support and Improvements σ i 2 α i = n σ 2 2 z + + Q n σ j iq σ z n j σ 2 2 z + σ j j =1 j=1 j=1 2 Performance Assessment Technical Evaluation Work Practices Technical Resource Uncertainty Design or Operational Trials and Testing Implement Processes Future Products Advice Field Problems Resolved Technology Best Practices Training

16 Performance by Compliance Formal Audit Formal Certification - UKAS Independent Agreed Term of Reference Performance Improvements by Review Allocation Reviews Informal Uncertainty Analysis Allocation Modeling Performance Assurance by Operations Documentation Operation Manuals Maintenance Manuals Best Practice Manuals In-Formal Audit Internal Operations Informal In -Formal term of reference Inspections Reviews Surveys SWOT Benchmark GAP Analysis Report Management Advise on Contracts Fiscal Audit Reports Metrology Report Mgmt Remote Monitoring Condition Based Monitoring Report Management Work Order Management

17 QUESTIONS PLEASE? or COFFEE