Abstract: The Moscow based OMEGA Company has developed and
successfully tested a new FOC-based monitoring system for
pipelines. The system can detect both human interference and
leaks with the precision of 2-5 m.
Key words: FOC, leak detection, pipeline security.
In April 2010, the state-owned Russian JSC Transneft
operating the world largest (appr. 43,000 mi long) oil and
oil products pipeline system announced the creation of the
OMEGA Company to install the OMEGA developed System of
Monitoring of Extended Objects (SMEO) based on Fiber Optic
Distributed Sensor System (FODSS) on all newly build
pipelines.
In February 2011 the OMEGA SMEO was for the first time
presented in the United States on the Pipeline Pigging and
Integrity Management (PPIM) exhibition and conference in
Houston, Texas, in May – on the Pipeline Simulation Interest
Group Conference in the Napa Valley. In 2012 the OMEGA SMEO
has been presented to participants of the PPIM European
round held in Prague
The OMEGA DTS
- Raman Scattering Principle
- Monitors pipeline at every 2 meter length
- Resolution of 0.3oC for 20 minutes time span
- Liquid leak rate of 2 m3 per hour is detected in 40-60 min.
- Detection time for gas pipeline is faster due to the cooling caused by the Joules-Thompson effect
- Thresholds can be configured for different areas
The System provides high-precision detection of location and
nature of acoustic vibrations, spatial displacements and
temperature characteristics of extended facilities such as
pipelines, oil wells, railways, highways, bridges and power
lines. The extended object is monitored through the whole
length of optic fiber used for the System`s sensor and not
requiring electric power along the line in real time mode.
The OMEGA DVS
- Coherent Optical Time Domain Reflectometry (COTDR) Principle
- Monitors the vibrations and third party interference along the pipeline with a resolution of 5 meters.
- The information is processed to classify different activities around the pipe, a.o.:
- Digging
- Mechanical Excavation
- Human Activity
- Vehicles Movement
In comparison to similar systems the OMEGA SMEO shows high
accuracy (± 5m) both of event detection on extended object
and sensor displacement (20 to 30 mm on 6 meter length in
any direction).
The OMEGA SMEO main option is the on-line monitoring the
vibro-acoustic field of the extended facilities. The OMEGA
SMEO monitors already a series of Transneft pipelines, in
August 2010 the installation of the OMEGA system on the East
Siberian Pipeline System built to transport Russian oil to
China began.
Monitoring of the temperature field of the extended object
provides integrated control over the production and
transportation of raw hydrocarbons from the well to the
shipment terminal. Since 2006 the OMEGA system is
efficiently employed by the OJSC Tatneft, Russia`s 5th rated
oil Company, in heavy oil production and steam injection
into the well.
At the trials conducted in December 2011 the newly developed
OMEGA Strains Monitoring Systems of Extended Objects (SMSEO)
registered the 20-30 mm bending deformation of a 6 meter
long 530 mm pipe. The test results offer the prospect of
implementation of the OMEGA SMSEO for instant registration
of soil and pipelines sections displacement.
To achieve most reliable results the optical cable is placed
about 1 m apart from the pipeline body. The FODSS includes a
Distributed Temperature Sensor (DTS) and a Distributed
Interference Sensor (DIS) as well as SMSEO (optionally). The
first is used as leak detection subsystem and can locate
oil, gas and other fluids leaks at distances up to 50 km to
each side of the allocation of the logical vodule. Space
resolution is 2 m and temperature change resolution ~ 0,3
deg.C on 20 min time leg. Leak rate of 2 cubic m per hour
can be detected in 1 h after the leak starts.
The DIS is used as third party interference (TPI) detector
and is based on the principle of phase-sensitive optical
time domain reflectometery. Virtual seismic sensors are
placed each 5 m. Algorithms used in DIS allow to classify
vehicles and various kinds of human activity near the
pipeline as well as digging and excavation attempts.
The OMEGA SMEO is based on Brillouin Optical Time Domain
Reflectometery (BOTDR). The spatial resolution does not
exceed 5 m, the stress resolution – 0,01 percent. The time
response is of the order of 10 min.
To secure best results the SMEO modules (Fig.2) are placed
at 50 km distance from each other.
At the same time the OMEGA Company keeps developing new
possibilities for the System implementation according to
demands of several application fields comprising now oil
industry and railways. At the same time a series of projects
of FODSS implementation on electricity grids and highways
are discussed.
Using the System`s advantages the OMEGA Company begins it`s
expansion on international market. In February of this year
a series of field trials on a pipeline near the city of
Bryansk in Central Russia for representatives of
international oil companies began, the first to visit this
site were representatives of the Caspian Pipeline
Consortium.
“The fiber optic cable system for remote detection of any
hazard impacts and soil compressions along the pipelines is
recognized as one of the most advanced engineering
developments … The system that consists of a cable network
and recording computer hardware was developed in a joint
project of U.S. Department of Energy/Gas Technology
Institute (Des Plaines, IL) and El Paso Corp., Houston” (1).
The extract is quoted from the analytical presentation “The
American experience in combating pollution of oil and oil
products” by Abalkina, I.L., Korneev, A.V., published by the
Institute for the USA and Canada Studies in June 2003 (2).
At that time the scientists referred to the valuable
international experience and “know-how” in use of fiber
optic sensors for the purpose of secure protection of gas
and oil delivery systems. Meanwhile, a group of the devotee
Russian scientists were conducting then the first field
tests of a similar system at the Moscow region testing
ground. By now, the system has already been widely used in
Russia.
What is meant here is the novel development designed by a
Russian company “Petrolight”. Now, operating as part of CJSC
“OMEGA” (a joint venture with JSC “Transneft”), the company
equips every new pipeline constructed by the Russian oil
transportation monopoly with the Systems of monitoring
extended objects “Omega”, designed by the Russian scientists
and named LDAMS (Leak Detection and Activity Monitoring
System ) when applied to pipelines.
It should be noted that the physics concepts, on the basis
of which the systems built around fiber optic sensors are
being operated, were discovered decades ago. These sensors
have a number of obvious advantages, among which are high
sensitivity, excellent extreme temperature performance,
achieved, in particular, by installation of specially
designed cables, insensibility to electromagnetic fields,
electrical inertness, no electrical shock hazards, and fire
and explosion safety. Not less important is the corrosion
resistance, and as a consequence, considerably long-life
operation of fiber optic sensors, multiplexing of
homogeneous and heterogeneous sensor data, and not least, a
moderate price for the developed systems.
When it comes to the product, designed by “Omega”, the
undeniable benefit of its SMEO is the most accurate event
location equaling 5 meters. Meanwhile many reputable
companies can locate the fluid leak on the basis of a
detailed data analysis of pressure, flow rate and
temperature, with account of the pipeline length, within the
accuracy of 50-400 meters. It is, indeed, another
qualitative indicator, particularly in view of environmental
aspects and with regard to the fact that most pipelines in
Russia are buried underground.
We should also think of the important “psychological” merit
of fiber optic cables as compared with efficient but rather
complicated and expensive monitoring systems fitted with
video surveillance cameras or satellite communication
facilities: there is no much point in protecting a fiber
optic line buried along the pipeline against hazardous
intrusions.
Hence, the range of parameters that can be measured by fiber
optic sensors is quite extensive. These are the temperature
and temperature change dynamics, absolute and gauge
pressure, linear-and-angular movements and the rate of
speeding up. The use of high-stable materials and
application of cutting-edge technologies make it possible to
produce ultra-high accuracy sensors. Thus, technical
solutions, applied by the engineers of SMEO, allow to
measure pressure with an accuracy up to 0,02-0,03 % at the
high end, with temperature effect of 10-3%/С. (3)
Apart from the conventional sensors, the sensors of liquid
level and phase interface, gas phase composition and others
are produced on the basis of fiber optics, being of the
utmost interest to oil and gas industries.
Recently, distributed sensors of physical properties have
been developed on the basis of laboratory researches. In
application thereof, optic fiber serves as both a data
transmission medium, and a complex of sensors.
The main characteristic properties of such sensors are as
follows:
- the principle of virtual splitting of optic fiber into
separate channels/bands enables to flexibly control spatial
resolution, and the position of sensitive environments as
well;
- ultra-low-loss of optical emission (up to 0.2 dB/km)
allows to generate stable sensitivity at a considerable
length of tens of kilometers (for LD and AMS «Omega» it
means 50 km on either side of the logic module);
- due to application of the location principle the sensitive
elements provide precise addressing;
- due to application of optical principles, in particular
interferential ones, high sensitivity is achieved;
- the linear part of the system is electrically inert,
resistant to electromagnetic fields, and can induce no such
fields;
- the system structure maintains continuous self-check of
the optic cable condition.
The distributed optical sensor is based on reflectometric
techniques, similar to that used in a reflectometer, a gauge
to measure the loss in optical fibers (4).
With high sensitivity command, LDAMS «OMEGA» can be applied
for the purpose of detecting pipeline ruptures or small
leakages amounting to hundreds of liters per 5 minutes. The
fluid flowing under high pressure generates the acoustic
wave detected by optic cable.
Until recently all this referred solely to the lab or
simulated field tests, since the “Omega” Systems are mostly
being run along the Russian pipelines. However, on May 15,
2011, the LDAMS «Omega» first time detected the actual fluid
leak. (5) It was pinpointed in the course of works for
adapting the System to the pipeline LLC
“RN-Yuganskneftegas”. The LDAMS detected and identified the
fluid leak in 450 meters from GPS in 426 mm Ø low pressure
water pipe of the formation pressure maintenance system,
running from GPS-1 (a group pumping station) to inventory
number 36301071.
In addition to the already applied ones science and research
departments have developed a detection algorithm of infra
low frequency changes, with operating frequency of < 0.1 Hz.
Such signals emerge in the System when the temperature
changes as a result of sensitive optic cable being heated by
hot oil, flowing out of the rupture. The tests proved high
probability of detection of the pipeline rupture with the
outflow rate up to 10 l/min at a temperature of 25 C. At
that, the rupture is detected just a few minutes after the
fluid reaches the cable surface.
Another major accomplishment of a research scientist group
is the completion of development of Brillouin reflectometer
to monitor strain generated in pipes of cross-country
pipelines, and also their spatial displacements. Strain
monitoring will help to track the causes of pipeline
deformation, among which are karsts, creeps and soil
expansion, which will enable pipeline companies to take
immediate action to prevent unrecoverable deformations. This
technology is expected to attract not only pipeline
operating companies, but also railroad companies, for which
the information about deformation of railway embankments is
safety critical, the more so, its time history.
We would also like to emphasize that distributed fiber optic
data measurement systems find ever-widening applications not
only in oil transporting, but also in oil extraction fields.
Using such sensors enables, within only a few hours, to
obtain a number of diagrams of the temperature distributed
throughout the well, and to accurately estimate the flow and
injection profiles. Moreover, compared with the systems
based on point-mode temperature sensors, each reading
provides real-time temperature profile throughout the well.
In fact, the technology described above, transforms the well
into a “smart deposit”, the exploitation of which enables to
optimize the machine capacity and enhance the well
productivity, and what is more, substantially increase the
oil recovery.
The physical properties as well as economic calculations
make the fiber optic systems effective and applicable in a
wide range of different energy fields. Thus, one of the
first developed technologies, connected with protection of
any patrolled perimeters against unauthorized intrusion, is
now becoming more urgent in view of preventing “third
parties” from approaching any kind of power stations or
pipeline engineering facilities. Furthermore, a project has
already been developed to facilitate practical application
of SMEO “Omega” to powerline protection, not only against
criminal encroachments, but also against excessive powerline
icing.
Versatility of the detected and processed data, as well as
ease of installation and low price for the sensor make SMEO
a unique “transformer”, on the basis of which the systems
with a spectrum of properties can be tailored to the
customers’ needs. Thus, a synergy of the described above
functions, provisionally named “smart deposit”, monitoring
of closed perimeters and temperature, along with empirical
applicability of the “Omega” systems to underwater
pipelines, affords to “sum up” the said properties into a
high-performance complex designated for secure protection of
offshore oil and gas platforms together with the pipeline
networks.
Speaking about obvious technological benefits of SMEO, and
LDAMS in particular, we cannot but mention such an important
aspect of their application as environmental friendliness
and protection. Actually, by obtaining the timely and
precise information on location and nature of a pipeline
rupture, the operating company can first thing avoid severe
economic losses. Moreover, split oil as well as most
transferred fluids, can cause serious, sometimes
unrecoverable environmental damage. In fact, using SMEO
provides us with a double advantage, I mean that its laying,
installing and operating induce no environmental damage.
This aspect as well as the company production competence
were confirmed by a Competence Certificate “For works which
can affect construction safety” granted to “OMEGA” in March
2011; and in May 2011, the specialized Institute of Ministry
of Internal Affairs provided the company with a Certificate
in respect of all the company products.(6) From now on, all
construction, commission and start-up works connected with
equipping pipelines and other extended LDAMS objects can be
performed independently by the company engineers. The
granted certificate applies to installing outdoor electric
power lines, mounting, commission and start-up works, and
also construction, reconstruction and overhaul.
As for the 1st of March of 2012, the fiber optic OMEGA Leak
Detection and Activity Control System has been installed on
appr. 4.000 km of the “Transneft” pipelines.
Meanwhile new functions of OMEGA Systems are developed, and
the first to mention is the OMEGA Pig Tracking Function
first introduced at the PPIM-2012 in Houston.
Passing through the pipeline, pigs come across the welded
connections, where they create some disturbances in the form
of pressure waves propagating in both directions with the
speed of the sound in the liquid.
Each disturbance of such matter creates λ-shaped waves
recorded by the chart recorder. The angle of the wave is
determined by its speed in the pipe (about 1050 m/sec) and
the length of the tracks depends on its attenuation, as well
as the sensitivity of the OMEGA System.
In some cases, the OMEGA Monitoring System captures the
pressure waves generated by the movement of the inspection
tool from the distance up to 30 km. The picture shows
λ-shaped waves indicating the movement of five pigs
simultaneously (Fig. 4).
Another possibility examined now at the Transneft operated
Baltic Pipeline System - 2 where the OMEGA Monitoring System
has been commissioned in November 2011 is the registration
of pressure waves. The OMEGA SMEO registers and identifies
pressure jumps resulting from changes in operating
conditions of the pipeline. On fig. 3 there are two such
jumps propagating on the “Transneft” BTS-2 pipeline from the
pumping station Unecha in direction of Andreapol (the
distance exceeds 500 km). The disturbance propagation speed
calculated on the basis of the tracks attenuation angles
equals to 1050 m/sec.
The mentioned trials on the BTS-2 showed another option
especially interesting for the security aspect of the
pipeline monitoring. The OMEGA System sensitivity permits to
track the location of a helicopter patrolling a Transneft
pipeline on low height. The OMEGA System allows to determine
the flight speed equaling in this case 140 to 160 km/h. One
of the options of the OMEGA Systems being under trials now
is the detection of gas leaks in different conditions
inclusive off-shore locations and permafrost areas. This
function is among the OMEGA possibilities most required on
international markets which is confirmed by our
internationally respected partners preparing to implement
the OMEGA System on oil and gas pipelines.
Reference Index
- 1. http://www.elpaso.com/
- 2. http://webcenter.ru/~akorneev/papers/rep-2301.html.
- 3. Innovation technologies for oil industry on the basis of
fiber optical data measurement systems/ Glushko S.I.,
Zazirniy D.V. Magazine «Science and Technologies of pipeline
transporting of oil and oil products », N 1, 2011 p. 85
- 4. “Phasesensitive fiber reflectometer for distributed
sensors of external actions / Gorshkov B.G.. Г. [and
others.] // Lightwave Russian Edition, 2005. № 4. P.47–49.
- 5. http://omega.mn/index.php?option=com_content&view=article&id=114:-lr-&catid=24:2010-12-04-12-44-49&Itemid=55
- 6. http://omega.mn/index.php?option=com_content&view=article&id=102:-lr-&catid=24:2010-12-04-12-44-49&Itemid=55
и http://omega.mn/index.php?option=com_content&view=article&id=127:--lr------&catid=24:2010-12-04-12-44-49&Itemid=55
- 7. http://omega.mn/index.php?option=com_content&view=article&id=121:-lr-&catid=24:2010-12-04-12-44-49&Itemid=55.