 Leak Detection Performance Pipeline Safety Trust Conference November 17 & 18, 2011 New Orleans, Louisiana

 Why Leak Detection?

Why Leak Detection? (Contd)  Minimize the volume of lost fluid  Reduce risk of fire, explosion or other safety hazards  Protect the company  Minimize cleanup costs with an early response to a leak warning  Protect reputation  Demonstrable acceptance of responsibility by executing a proactive leak detection program  Always increasing regulatory interest in pipeline integrity programs; including leak detection November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 3

History  Manual pressure/flow readings and evaluation  Voice communication between the field and any center of responsibility that may exist, or with other stations along the line  Familiarity with the pipeline behavior by controllers and technicians was critical  Right-of-way observation including walk-overs and fly-overs were among few leak detection options November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 4

Automated Measurements  Proprietary logging systems and SCADA  Transmitter and meter technology  Automation tools and products that acquire accurate information about hydraulic behavior  Tools to assist in evaluating the relationships among measurements November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 5

Leak Detection Performance  From the former API 1155 (Evaluation Methodology for Software Based Leak Detection Systems):  The system correctly indicates that there is no leak  The system correctly indicates that there is a leak  The system incorrectly indicates that there is a leak (false alarm)  The system incorrectly indicates that there is no leak (failure to detect)  Definitions absorbed into API RP-1130 (Computational Pipeline Monitoring for Liquid Pipelines) November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 6

Performance Metrics  Sensitivity – Combination of the size of a detectable leak and the time required to detect it  Reliability – A measure of the system’s ability to accurately assess whether a leak exists or not  Accuracy – The ability of a system to estimate leak parameters such as leak flow rate, total volume lost, and leak location  Robustness – The ability of a system to continue to function during unusual hydraulic conditions or when data is compromised November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 7

Meter-Based Leak Detection  Most widely used method on long haul pipelines  Requires meters at all entry and exit points  Achievable sensitivity limited by meter accuracy  Some methods can be implemented in SCADA; or are options with SCADA products  Some products are stand-alone and driven by SCADA data  Alarm thresholds must tolerate and expect the imbalance in meter readings as the line packs and unpacks  Leak evaluation algorithms that correlate actual changes in linepack with meter imbalance provide the best performance November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 8

API 1149 Performance Predictions  Predicts the theoretical best performance possible with configured uncertainties  No margin for false alarm prevention  Temperature uncertainty and related changes in density during transit is largest influence on performance  Not uncertainty in measurement, but uncertainty in temperature profile along the line  One type of leak detection system can more accurately estimate the temperature profile than other systems November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 9

Definitions  Dry Volume – Volume of the pipeline at atmospheric pressure and a reference temperature  Linepack – The incremental quantity of fluid in the line in addition to the dry volume influenced by pressure and fluid temperature  Linepack is heavily influenced by temperature’s effect on fluid density as is pressure, but often to a lesser degree  Profile – Value of a parameter over the length of the pipeline segment November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 10

Definitions (cont)  Uncertainty – Potential error in measurements that must be expected and accounted for; also the degree to which something is unknown and must be estimated or assumed based on somewhat related measurements.  Real-Time Transient Model (RTTM) – Accurately tracks fluid temperature/density profiles with consideration of pressure in order to reduce uncertainty in the linepack November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 11

Meter Quality vs. Performance November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 12

Meter-Based Leak Basics  Flow/Pressure/Temperature measurements only at segment end-points  Metered flow accuracy important for high sensitivity  Fluid density (molecules/mass per unit volume) varies significantly with temperature  Warm fluid is less dense; Cold fluid is more dense  Temperature/density profile uncertainty is the most limiting factor in leak detection for some pipelines November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 13

Volumetric Flow Measurement  Benefits of volumetric (not corrected for temperature and pressure) flow measurement  Barrel-to-barrel assessment tolerates differences in density at injection and delivery points  Tolerates switching injection sources of different temperatures  Useful on short lines with small changes in temperature/density during transmission  Not useful where temperature/density profiles are significant due to heat loss November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 14

Net barrel Flow Measurement  Benefits of net (corrected for temperature and pressure) flow measurement  Useful for custody transfer  Under steady-state conditions, fluid injected at lower density will balance with delivered fluid at higher density  Injections at slightly higher volumetric flow balances with deliveries at lower volumetric flow  Assumes a stable temperature/density profile November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 15

Net Flow Measurement Issues  Transient conditions thwart many algorithms involving net flow measurements  Line packing and unpacking still result in an apparent net flow imbalance as with basic volume balance methods  Net barrel flow measurements aggravate simple balance algorithms where a difference in density exists at injection and delivery points except under steady-state stable conditions November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 16

Natural Flow Imbalance  Difference in injected fluid density and delivered fluid density  Gradual change in fluid density during transit  Temperature/density profiles are poorly understood by most simple algorithms  Profile changes shape with changes in flow rate  Water crossings and occasionally wet soil increase thermal conductivity November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 17

Meter-Based Leak Detection Limitations  Accounting for changes or disturbances in linepack  Operational changes causes the line to pack or unpack as a normal occurrence  Short-term hydraulic disturbances (transients), including changes in injection temperatures, and their effect on linepack must be tolerated or understood in short-term evaluation algorithms used in rapid assessments  Over extended periods any effects of transients are diluted; thus allowing good sensitivity by most meter-based solutions over long observation intervals November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 18

Key Concepts  Pressures and temperatures under steady-state conditions provide current linepack characteristics  Divergence of meter readings (greater imbalance) should be reflected in linepack changes as seen in pressures  Transients disturb this information and can lead to significant short- term linepack uncertainty  Over long time intervals any observed variations in linepack become insignificant compared to the quantity of fluid passing through the pipeline system  Long-term sensitivity settings do not require as much tolerance of linepack uncertainty as do short term leak detection thresholds November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 19

Linepack Estimation  Fluid density assumed to be an average of injection and delivery density  Weighted average  Custom algorithms for curve fitting  RTTM thermal models track fluid density along the line  Change in flow rate alters the temperature/density profile as a new quiescent state develops November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 20

Profiles  Temperature  Occurs when injection and delivery temperatures differ  Subject to heat transfer characteristics of environment  Varies with flow rate / transit time  Pressure  Varies as batched fluids of different characteristics travel  Varies as batches of different densities travel over mountains  Profiles are accurately tracked by Real-Time Transient Models November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 21

Real-Time Transient Model  Most sophisticated volume/mass balance tool  Includes a thermal model to increase the accuracy of linepack evaluation, thus allowing a shorter detection time for a detectible leak  Tracks heat transfer along the line and develops accurate temperature/density profiles as step changes in flow rates or injection temperatures occur  Allows thermal model tuning to achieve the best performance by modeling the hydraulic behavior accurately  Automatic tuning capabilities  Instrument sanity checking November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 22

RTTM Myths  Software is expensive  Not significantly more expensive  Software requires special skills  Training and full technical support is offered by vendors  Knowledge of the pipeline physical details is needed  Software requires ongoing maintenance  Not needed, once performance is satisfactory, but further tuning is often performed to continually improve performance  Required if the pipeline network is changed November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 23

Static Pressure Testing  Extremely high sensitivity  Zero (0) flow results in zero (0) uncertainty in flow measurement  Works well in a relatively incompressible liquid environment  Requires pressure control equipment November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 24

Static Pressure Testing (contd)  Shut in under pressure at near operating pressure  Monitor pressure decay for a period of time  Drop pressure by half  Monitor pressure decay for a period of time  A consistent pressure decay rate indicates decreasing density due to heat transfer  A different pressure decay rate indicates a leak whose rate is pressure dependent November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 25

Static Pressure Test Trends November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 26

Conclusion  Simple linepack assessment algorithms have a place where linepack is stable and linepack variations and uncertainty do not adversely affect leak assessment  RTTM technology significantly reduces linepack uncertainty in transient environments and enables leak detection approaching the limits imposed by meter accuracy  Static pressure testing is a useful integrity verification tool  Matching the proper tool to the pipeline’s operation is critical November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 27

Training & Response  A critical component of any pipeline integrity management program  Response protocol should be included in training and be enforced  Controller can shut down the line on any suspicion of a leak  Details regarding actions, reporting, etc.  No internal penalty for reasonable judgment  A culture focused on pipeline integrity management is critical November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 28

References  API 1130 – Computational Pipeline Monitoring for Liquid Pipelines  API 1149 – Pipeline Variable Uncertainties and Their Effects on Leak Detectability  API 1161 – Guidance Document for the Qualification of Pipeline Personnel  49 CFR Part TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS  49 CFR Part TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 29

Contact UTSI UTSI - U.S. Headquarters 1560 West Bay Area Boulevard Suite 300 Friendswood, Texas USA Telephone: Fax: WWW: Daniel W. Nagala ( ) President & CEO November 17 & 18, 2011 Pipeline Safety Trust 2011 Pipeline Safety Conference 30 UTSI - Europe Raimundo Fernandez Villaverde 43, 6L Madrid, Spain Telephone:+34 (91) Fax:+34 (91) WWW: Catalina Frey ( ) Senior Consultant Daniel W. Nagala ( ) President & CEO