[Oil & Gas White Paper] Getting Ahead of the Game: adopting best practices in leak detection

Getting Ahead of the Game:
adopting best practices in
leak detection
May 2013 / White Paper
Make the most of your energySM

Summary
Executive summary ................................................................................... p 1
Introduction ............................................................................................... p 2
CPM methods for pipeline leak detection.................................................... p 4
How to choose or evaluate a leak detection system.................................... p 5
High consequence areas ........................................................................... p 6
API 1149 .................................................................................................... p 7
Leak detection challenges ......................................................................... p 8
External based leak detection .................................................................... p 9
Real-time transient model vs. other CPM’s.................................................. p 10
When you want volume balance CPM......................................................... p 11
When you want a real-time transient model................................................. p 12
Association of oil pipe lines rupture monitoring............................................ p 13
Conclusion ................................................................................................ p 14

Executive summary
Getting Ahead of the Game: adopting best practices in leak detection
Burgeoning energy exploration is driving the construction of pipeline systems for
hydrocarbon transportation. For a variety of reasons, including renewed scrutiny
on safety by regulators, this is also driving new practices and standards for
leak detection.
Computational pipeline monitoring (CPM) systems use real-time information
from the field – such as pressure, temperature, viscosity, density, flow rate,
product sonic velocity and product interface locations – to estimate the
hydraulic behavior of the product being transported and create a computerized
simulation. With it, controllers can be alerted to abnormal operating conditions
that might signal the existence of a pipeline leak. Different CPM methodologies
provide different leak detection capabilities, so different methods, or a
combination of methods, might be better applied to different operations.
Selection of the right CPM for a given company or given pipeline relies on
the thorough evaluation of several factors, including pipeline characteristics,
business objectives, additional risk factors and special safety concerns, such
as proximity to environmentally sensitive or urban areas. New standards and
industry initiatives provide tools to assist in this evaluation, ensuring
the pipeline industry continues to provide efficient, effective and safe
hydrocarbon transportation.
White paper | 01

Introduction
White paper | 02
Kalamazoo River, Mayflower, Grand Marsh, Bonga Field, Little Buffalo – all
places that represent the sites of pipeline spills in the last several years. The
rash of significant incidents has many countries spending more and more
time investigating the pipeline industry’s safety practices. This comes at a time
when the opening of new oil and natural gas plays around the world is putting
growing pressure on new pipeline development.
Changing attitudes around the world necessitate that pipeline companies
vigorously take on the goal of increased safety and reassess their abilities to
detect and mitigate product leaks. The consequences of not doing so endanger
not only the business of individual companies but the reputation of the industry
as a whole.
The positive side of this discussion is that significant investments have been
made in recent years to develop a new array of industry standards and best
practices, as well as continual advancements in the technology that supports
leak detection.
Of all the different methods for detecting pipeline leaks, what’s observed on
the control room operator’s console is almost always the best warning system.
Computer-based leak detection is a common industry application that supports
the safety of the general population and environment and helps sustain efficient
operations and facility management. This paper provides an overview of
liquids pipeline leak detection best practices based on Computational Pipeline
Monitoring (CPM) software applications. These best practices follow dictates
of governmental regulations in place or proposed worldwide, as well as
recommendations from leading industry agencies.
More importantly, this paper discusses the process for selecting the best leak
detection system and reviews the best practice criteria operators need to
consider. The goal is to help companies find the right intersection between risk,
cost and above all else, safety.

CPM methods for
pipeline leak detection

White paper | 04
CPM methods for pipeline leak detection
The most common technology for detecting
pipeline leaks is the CPM system, which uses real-
time information from the field to estimate volume,
mass or the hydraulic behavior of the product
being transported. An example of a hydraulic profile
display is shown in Figure 1. Calculated results
are then compared to field references to identify
an unexpected anomaly that might signal a leak –
whether an accidental rupture or an unlawful tap.
An example of leak detection is shown in Figure 2.
The American Petroleum Institute (API) publication
1130 defines CPM systems as systems that are
internally based, utilizing field sensor outputs
that monitor internal pipeline parameters such
as pressure, temperature, viscosity, density, flow
rate, product sonic velocity and product interface
locations. Which parameters are considered and
how they are interpreted depends on the CPM
method being applied. The following is a brief
description of the common CPM methods in use
on pipelines today:
• Line balance – measures the imbalance between
the receipt and delivery meters. This is your basic
“meters in, meters out” comparison and is the
least sensitive to anomaly capture as volume in
the pipe is not part of the balance
• Volume balance – similar to the line balance but
also includes a limited pipe volume adjustment.
An overall pipeline density is calculated based on
pipeline boundary pressure and temperature
• Modified volume balance – similar to volume
balance except a different volume adjustment is
used for each product in the pipeline. This takes
into consideration where the density changes are
in the pipeline
• Pressure/flow rate modeling – essentially
what a controller does by nature, looking for
unexplained large drops in pressure or flow, but
there are applications that monitor for these
anomalies to ensure these large changes are
not missed
• Acoustic/negative pressure wave – detects
a leak by quickly sensing a pressure wave and
using those detections to triangulate the location
of the event/leaks
• Statistical leak detection – pressure and flow
inputs that define the perimeter of the pipeline
are statistically evaluated in real time for the
presence of patterns associated with a leak
• Real-time transient model – all the fluid dynamic
characteristics are modeled, including line pack,
slack, shut-in and transients, under all pipeline
flow conditions. A very detailed configuration with
very fast calculations and the ability to model
hydrocarbons in any phase
Important differentiators between real-time transient
model detection systems and volume balance
systems include increased leak detection sensitivity,
fewer false alarms and better leak location
estimation. These differentiators allow real-time
transient models to perform leak detection across
a wide range of pipelines, from simple to complex,
transporting many different products under a broad
range of operating conditions. They are key to
help improve and facilitate effective response
times, especially in environmentally sensitive
and urban areas.
Figure 1
Figure 2

White paper | 05
How to choose or evaluate
a leak detection system
The multitude of choices for leak detection systems is necessitated by the
vast variety of pipelines they will be employed on. Therefore, a comprehensive
analysis is necessary to identify which CPM technologies and methods
are best suited for the pipeline assets in question. A simple A-to-B pipeline
route might have simpler operations than a pipeline with many active route
connections and elevation changes, multiple receipt and delivery points, and
reversible flow. As the complexity increases, the CPM to be applied needs to
be flexible enough to handle all operational scenarios possible in the operation
of the pipeline.
The following is a listing of key factors to be considered when evaluating
a new CPM or re-evaluating a legacy CPM for its leak detection capability.
Factors should be weighted according to their importance to any
particular operation:
• Rate of false alarms and misses
• Sensitivity to pipeline flow conditions such as transients, shut-ins, starts,
and stops
• The impact of instrument accuracy and configuration accuracy
• Personnel training and qualification requirements
• Required response time
• Leak location estimation and release volume estimation accuracy
and precision
• Ability to detect pre-existing leaks
• Robustness/high availability
• Initial cost/tuning costs/maintenance costs
The most important objective in selecting a leak detection system is that the
chosen solution must be able to assist the controller in identifying a leak event
within a sufficient period of time that mitigates the safety and environmental
risk to a level that is acceptable for the stakeholders in a particular pipeline,
while also meeting the operating company’s overall business objective
and threshold for risk. This includes the potential value of product lost,
the cost of clean-up and potential regulatory fines, potential detriment to
surrounding environments and the cost to reputation and potential impact
on future projects.
The most important objective in
selecting a leak detection system is
that the chosen solution must be able
to assist the controller in identifying
a leak event within a sufficient period
of time that mitigates the safety and
environmental risk to a level that
is acceptable for the stakeholders
in a particular pipeline, while also
meeting the operating company’s
overall business objective and
threshold for risk.

White paper | 06
High consequence areas
When analyzing which leak detection systems
to employ, the question of whether the pipelines
being monitored are located close to or in
high consequence areas (HCAs) must be
answered. High risk, or high consequence
areas are defined as areas where a pipeline
leak will have a significant impact on people,
property, the environment, or all three. Whether
through regulation, local authority or community
requirements and expectations, HCA’s typically
demand higher levels of leak detection capability
and sensitivity to mitigate the higher risk
of significant consequences from a leak.
If located in such an area, pipeline operators
must take additional measures to meet these
requirements. These measures include conducting
a more thorough risk analysis and employing
additional leak detection measures to enhance
public safety and protect property and
the environment.
• Automating data collection for
over-short analysis
• Integrating alarm and status information
between connected pipelines
• Use of, or more frequent, operational
shut-in tests
• Addition and/or the relocation of instrumentation
• Application or tighter parameters on pressure/
flow deviation monitoring
• Higher degree of data integration between
operations support applications
• Deploying a higher fidelity leak
detection application
If the pipeline network has locations close to or
in high consequence areas (HCAs) – or if it is a
large and complex network with diverse operating
parameters and products – more than one leak
detection system might be warranted. A
multi-tiered approach might be necessary
to satisfy specific requirements.

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API 1149
Although an American standard, the API 1149 is
a best practice evaluation around the world. This
is a theoretical analysis of a given leak detection
system’s ability to detect a leak of a given size,
based on the specifications of a given pipeline.
It weighs the time to detection against the size
of the leak.
While not always necessary to employ techniques
that achieve the lowest theoretical capability as
determined by 1149, it provides a measure to weigh
against when analyzing the cost of leak detection
systems against the risk of undetected leaks. As
important, if not more so, the API 1149 calculations
can assist pipeline operators in determining
the benefit of specific pipeline infrastructure
enhancements on their leak detection capability. For
example, what increase in leak detection sensitivity
can be achieved by adding, replacing, or upgrading
instrumentation on all, or sections of a pipeline.

White paper | 08
Leak detection challenges
Successful pipeline leak detection can present
many challenges to the operator. Issues that
impact leak detection include:
• Batched systems – multiple products; multiple
phase products; reversible flow systems
• Transient and steady state flow conditions;
turbulent and laminar flow transitions
• Step change product temperature gradients;
elevation induced hydraulic variations, such as
over a mountain or under a shipping channel
• Varying P/L diameters, telescoping systems,
restrictions, block valves, tees, relief systems,
control valves and unique
physical characteristics
• Multiple pump configurations – series, parallel,
varying and multiple speed, electric and
engine drives
• Branch connections and multiple inlets, outlets
and partial flow alignments
• Slack line and product separation
static conditions
• HVL versus crude versus condensate versus
refined products physical property and hydraulic
characteristics operated within a single
SCADA console
• Communication outages; variable signal scan
and refresh rates; errant signal and data filtering
versus non-HCA system variances
• Human factors – operator sensory
overload; fatigue
• Varying individual operating procedures
• Employee turnover and limited training time for
new controllers
• External and internal resource availability
When evaluating leak detection needs and
effectiveness, these should be evaluated to
determine their impact. Mitigation of many of
those listed above will be directly related to the
CPM chosen for the pipeline. Others, such as
human factors of operator overload and fatigue,
will rely on the implementation of control room
management, human machine interface and
training best-practices.

White paper | 09
External based leak detection
External based leak detection systems are being
increasingly employed due to their abilities to
detect very small spills and locate leaks with a
high degree of accuracy. Technologies include
hydrocarbon sensors, thermal imaging, acoustic/
pressure wave sensors and fiber optics.
Unfortunately, while external technologies can be
retrofitted to existing pipelines, the fieldwork to
do so is still relatively expensive, increasingly so
the longer the pipeline. However, new and shorter
pipelines are increasingly using external
technologies and more and more these
technologies are used in conjunction with
a CPM based leak detection applications.

White paper | 10
Real-time transient model
vs. other CPM’s
As operators walk through the above checklists,
eventually a point is reached where decisions
need to be made on selecting a leak detection
system. Again, the selection should match the
characteristics of the pipeline as closely as
possible and fit the company’s business goals
and risk threshold.

When you want volume
balance CPM
White paper | 11
While less robust and not well matched to
complex pipeline systems, volume balance CPMs
can offer effective, and cost-efficient solutions
for companies with low risk/low consequence
systems, such as:
• Pipelines generally operating in steady state
conditions and non-HCA areas
• Pipelines with shorter segments and
steady temperature
• Pipeline operators whose risk assessment calls
for a lower fidelity leak detection system
• Pipeline operators who want to provide some
level of interim leak detection coverage while
a higher fidelity model is being deployed
or upgraded

When you want a real-time
transient model
White paper | 12
For pipelines that operate in HCA’s and for the risk
averse pipeline operator, the real-time transient
model is unmatched in its ability to support highly
effective leak detection for high risk, or complex
pipeline systems:
• Great for both steady state, transient and
shut-in conditions
• Leak detection thresholds well under one
percent of flow are possible
• False alarm rates significantly lower versus other
leak detection systems
• Leak location and leak volume estimation
• Excellent leak detection performance with
compressible products
• Accounts for use of drag reducing agents
in pipeline
• Leak detection for pump stations and tank farms
• Two phase model maintains leak detection
through slack line conditions
• For expedited permitting on new pipelines

Association of oil pipe lines
rupture monitoring
White paper | 13
Although leak detection technology has
advanced a long way in terms of detection time
and detectable leak size, damaging pipeline
ruptures and large volume release events have
still occurred and, unfortunately, been missed. In
addition to individual companies taking initiative
to improve their leak detection capabilities using
the strategies discussed above, the Association
of Oil Pipelines (AOPL) has created a Leak
Detection Rupture Monitoring project as part of
their “Pipeline Leadership Initiative” to develop
additional strategies to continue improvements in
leak detection.
A key area of improvement the initiative has
identified is execution on the “3R’s”: Recognition,
Response and Reporting. They have developed
performance standards for the industry to follow in
this area, with the target goal of 30 minutes for
3R execution:
Recognize (5 minutes): Recognize a 50% flow
change within five minutes.
Response (5 minutes): A response to the rupture
must come within five minutes of the recognition.
Responses can be tailored to particular situations.
Report (20 minutes): A report must come within
20 minutes.
While these may seem like basic standards,
meeting them is important to the goal of the
industry to be “great” in the execution of the 3R’s
of rupture detection.

Conclusion
Technological advances and aggressive exploration are opening up more and
more hydrocarbon sources around the world. This will mean an increasing
demand for pipeline development.
It will also mean increasing pressure for pipeline operators to demonstrate and
maintain effective safety practices, namely in leak detection and prevention,
as regulators place more scrutiny on projects. Not only is this important
for individual companies to maintain competitiveness in the market but it is
important for the reputation and health of the industry as a whole.
The upside is with greater focus on leak detection comes more advanced
solutions and industry standards for guidance. CPMs provide a wide array of
powerful solutions for pipeline companies to identify leaks, and even potential
leaks, faster and with greater accuracy. Industry guidelines and assessment
tools, such as API 1149 and AOPL rupture monitoring, give companies the
tools to evaluate their program and implement the appropriate solution.
Whether choosing a volume balance CPM or a real-time transient model, the
selection needs to be based on a thorough evaluation of the business objective
against the threshold for risk. At the intersection of those points is where
companies will find the appropriate leak detection system solution.
White paper | 14

[Oil & Gas White Paper] Getting Ahead of the Game: adopting best practices in leak detection

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