Pipeline Potential Leak Detection Technologies: Assessment and Perspective in the Nigeria Niger Delta Region

doi:10.4236/jep.2011.28121

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Journal of Environmental Protection, 2011, 2, 1055-1061

doi:10.4236/jep.2011.28121 Published Online October 2011 (http://www.scirp.org/journal/jep)

Pipeline Potential Leak Detection Technologies:

Assessment and Perspective in the Nigeria Niger

Delta Region

Jasper Agbakwuru

Offshore Technology, Faculty of Science and Technology , University of Stavanger, Norway

Email: [email protected]

Received August 9th, 2011; revised September 11th, 2011; accepted October 7th, 2011.

ABSTRACT

This paper examines the advances in pipeline third party encroachment alert systems and leak control methods in the

oil/gas industry. It also highlights the extent of spill/pollution issues in the Niger Delta region due to intended/unin-

tended damages and suggests a possible method of control. It is believed that the best option to avoid pollution due to

pipeline fa ilure is to ensure that hydrocarbon does not exit fr om the pipeline. With the different methods considered in

this review, acoustic monitoring of change in the operational sound generated from a given pipeline section is sug-

gested to be practicab le to identifying sound abnormalities of th ird party encroachments. One established challeng e of

the acoustic system for buried pipelines protection is attenuation of acoustic transmission. An attempt to check the per-

formance of an acoustic transmission on steel pipelines submerged in water points to a similar research on plastic wa-

ter pipelines that a ttenuation is small compared with pipe buried in soil. Fo rtunately, Niger Delta of Nigeria is made of

wetland, swamps and shallow water and co uld therefore offer an oppo rtunity to deploy acoustic system for the safety of

pipelines against third party attacks in th is region. However, the numerous configura tion and quantity of oil installation

in this region imply that co st of application will be enormou s. It is therefore suggested that a combination of impressed

alternating cycle curren t (IACC) which traces encroachment on the pipeline coating and an acoustic system be used to

manage intended and unintended pipeline potential damages. The IACC should be used for flow lines and other short

distance delivery lines within the o ilfield, while the relatively large diameter and long length delivery, trunk and trans-

mission lines should be considered for acoustic p rotection. It is, however, noted that further efforts are required to re-

duce cost and improve effectiveness of these systems.

Keywords: Pipeline, Leaks, Detection, Niger Delta, Oil Spill, Oil Pollution

1. Introduction

Due to environmental, economic and social cost of hy-

drocarbon leaks, the oil and gas industry places great

importance to the need to minimise ugly events of oil

spill or pollution from occurring. The causes of pipeline

leaks could be categorised into four main classes: Opera-

tional, structural, unintended or intended damages [1].

Operational class includes all leaks from operation of oil

and gas pipelines such as equipment failure (for instance

flange sealing problems due to damaged seals or loose

bolts/nuts), human error etc. Structural problems include

the failure of pipeline in burst, collapse, fatig ue, fracture,

buckling, corrosion (wall thickness loss), and internal

loadings etc. The intended damages come in the form of

terrorist attack, sabotage/theft. The unintended damages

are those that are often caused by construction workers

working in the vicinity of the pipeline.

While it is fair to put that as at today, the industry have

made some significant efforts in building barriers against

the activation of first two classes, there are still chal-

lenges in the latter two, especially, related to cost and

effectiveness.

In describing the problem, Yo-Essien of Nigeria oil

spill detection and response agency (NOSDRA) believes

that the enormous oil installations deployed in the Niger

Delta region explains their vulnerability to vandalism.

Presently, the Niger Delta region plays host to 600 oil

fields of which 360 fields are onshore while 240 are off-

shore with over 3000 kilometers of pipelines crisscross-

ing the region and linking some 275 flow stations to

various export terminals. The main area of the delta is

Pipeline Potential Leak Detection Technologies: A s sessment and Perspective in the Nigeria Niger Delta Region

1056

about 46,200 km2 (equivalent to about 1/20th of the area

of the country). According to him, it is pertinent to note

that oil spills resulting from pipeline vandalism has con-

tinued to be a challenge, with most incidents alon g major

pipelines and manifolds [2].

Considering the situation in the Niger Delta of Nigeria,

it is imperative that the different methods and available

technologies be studied in order to suggest a strategy for

research and development in handling the challenges in

the protection of oil and gas pipelines against growing

intended an d unintende d damages.

This paper is motivated by the importance to have full

control of the pipeline against intended and unintended

damages. Recently, the Directorate of Petroleum Re-

sources (DPR, Nigeria) claims that activities of oil theft

cost Nigeria about 300,000 barrels per day. It is also re-

ported that Nigeria lost about $1.5 billion yearly to the

crude oil theft [3]. Of recent, the Chairman of SHELL

Nigeria, claims that the criminal gangs continue to steal

oil from SHELL pipelines at estimated rate of 100,000

barrels per day [3] The Managing Director of SHELL in

his response on the recent publication on oil spill in the

region by the Amnesty International, firms that without

addressing the complex issues in the Niger Delta, and

without all stakeholders playing their part, this problem

will continue to be on th e increase [4]. This is evident in

the statistical oil spill data sh own in Figures 1(a) and (b)

for 2011.

The recent oil spill data from SHELL Nigeria, the

largest oil producing company in Nigeria, indicate that

the majority of the spills have been caused by sabotage

or theft. The recent spill statistical data is shown in Fig-

ures 1(a) and (b).

The several thousands of human lives lost, millions of

barrels of oil spilled to the fragile environment, thou-

sands of people displaced from their homes and millions

of dollars (US) of property destroyed in the region by

pipeline failures have been documented in the literature

[5-7].

Construction/digging activities with improper supervi-

sion and survey in brown fields lead to unintended dam-

ages. Most often, due to fear of consequent liabilities, the

pipeline operator is often not informed of such damages

by the intruding construction contractors or persons, ex-

cept perhaps when such damages result to obvious im-

mediate spill/pollution. Unfortunately, most of these un-

intended damages in the form of external coating dam-

ages, kinks, gouges and dents deteriorate with devastat-

ing consequent failure months or years later causing

safety, environmental and public concern.

This is also a global issue. Chastain (2009 ) quoted the

API recent report of pipeline failure incident in United

States between 1999 and 2006: 77% fatalities, 49 % inci-

(a)

(b)

Figure 1. (a): Showing the 2011 Oil spill monthly statistics

from pipelines of Shell Nigeria; (b): Showing some yearly

oil spill statistics from pipelines of Shell Nigeria. (Source:

SHELL Oil Spill 2011 data.

http://www.shell.com.ng/home/content/nga/environment_so

ciety/respecting_the_environment/oil_spills/).

dent involving evacuations, 41% of barrels released by

right of way incidents, 27% of incidents involving a re-

lease of 50 barrels or more [8].

Clearly, the prevention of damage to the pipeline must

be an industry priority. Unfortunately, pipeline operators

appear to have inadequate cost effective industrial tech-

nology to manage most of the pipeline exposures that

generates pollution, sp ill or loss of hydrocarbon oil from

containments such as pipelines in the class of intended

and unintended actio ns. It is noted that till date, there h as

never been an effective solution for securing pipelines

against damage caused by terror, sabotage, theft [9,10].

A lot of patents and methodologies have been devel-

oped for the pu rpose of leak identificatio n using acoustic

signatures [11]. These efforts in our opinion is reactive in

nature and a proactive action is required in preventing

exit of oil content of oil pipelines uncontrollably to the

environment with its attendant environmental, economic

and social consequences.

Pipeline Potential Leak Detection Technologies: A s sessment and Perspective in the Nigeria Niger Delta Region1057

In this paper, various methods of hydrocarbon spill/

leak control and barriers used by the industry today have

been considered. Most of the review of the technologies

in this work is on an industrial context. Therefore it will

be discussed with reference to the work of pipeline in-

tegrity maintenance and inspection companies most of

whom are members of the Offshore Technology com-

munity [12]. This group has been selected as they are

among the known major operators of innovative and

modern systems for pipeline integrity systems, leaks and

maintenance.

2. Review of Leak Detection Methods

The methods and techniques for the detection of hydro-

carbon leaks from pipelines as used by the oil and gas

industry to-date is reviewed and can be categorised into

nine main classes based on the principle of operation (see

Table 1). Details of these methods have been detailed in

a review of the Pipeline Leaks and Inspection Technolo-

gies in the Oil and Gas Industry [13]. It is noted that

most of the system above could be integrated to the Su-

pervisory Control and Data Acquisition (SCADA) for

alert systems in line with API RP1167.

There has been a recent development in the observa-

tions of leaking pipelines in muddy water. This devel-

opment became necessary due to the underwater poor

visibility inheren t in the Niger Delta region, especially in

the wet season [14]. Further work is in progress to en able

the system to operate remotely to locate leaks.

The methods tabled in Table 1 have been identified to

be useful in two areas:

1) Identifications of available leaks irrespective of the

class of the causal damage

2) Potential leaks identification due to metal loss

(corrosion, gouges etc.).

3. Review of Potential Leak Detection

Methods

These are controls that are in place to stop or prevent

events that would otherwise lead to escape of oil from

the pipeline.

3.1. Acoustic Systems

The acoustic impact detection system often comprise of

multiple acoustic sensors, power supply and remote

transmitting devices which are placed along the pipeline

at fixed intervals.

Pipeguard technology developed by Magal Security

Ltd (Israel) is perhaps one of the recent technologies in

this field. The company has been granted a research and

development grant in March-2011 to further enhance its

PipeGuard technology for protection of gas pipelines.

Multiple Pipeguard sensors are typically interconnected

Table 1. Categorisation of leak detection methods.

Leak detection methods

SN Method Examples of tool/systems that use the

method

1Laser Scanning Laser scanning, Buckle detectors, etc.

2Ultrasonic Intelligent pigging, Automatic

ultrasonic tester, TOFD, Ultrasonic

probe testers etc.

3Acoustic Acoustic Leak detector, hydrophones ,

Electromagnetic Acoustic T ransducers

(EMAT), piezoelectric meter etc.

4Fibre Optics Optical sensors (for leak, strain, fatigue

and ground movement detection), etc

5Visual Inspection Use of human eye, Inspection light,

Robotic crawlers etc.

6Magnetic flux

leakage method Int elligent pigging, Eddy current,

Magnetic particle inspection etc.

7Inventory accounting

(pressure differentials,

mass flow-rates etc)Negative pressure wave detectors

8Flourometry/

Hydrocarbon Leak

detection sensors

Fluorescence detectors, Hydrochemical

detectors.

9Temperature based

sensors Thermal spray technology etc.

by wireless or cellular mesh network and alarms are dis-

played on geospatial map before the damage is done.

Reception of raw seismic signalling is achieved using

several geophones in a row, highly sensitive to the fre-

quency domain, typical to the act of digging. The loca-

tion of the identified threat is derived from accurate

measurement of the signal at each sensor both in term of

direction and distance from the unit [9]. The company

has extended this to th e use of infrasonic seismic sensors

with the ability of identifying threats based on their

acoustic signatures. The sensors are installed few feet

above the pipeline structure [8].

General Electric (GE) developed a related system

popularly called ThreatScan. The ThreatScan is used for

both buried and above ground pipelines. The power sup-

ply is solar with a battery back-up for “no sun” condi-

tions. Each sensor communicates directly with the satel-

lite system and relays data to the GE’s monitoring facil-

ity where it is analysed [8,15]. It can be used for Sabo-

tage warning and detection of illegal hot tapping (prod-

uct theft) but in our opinion, the characteristic alert noti-

fication up to 0 - 30 mins is adequate to pipeline intru-

sion to happen uncontrolled, jeopardising the essence of

the system. This tool is currently in use by some pipeline

operators in the USA.

3.2. Patrols and Satellite

Pipeline patrol and Security guards is the act of patrol-

ling the pipeline right-of- way (ROW), keeping watch

Pipeline Potential Leak Detection Technologies: A s sessment and Perspective in the Nigeria Niger Delta Region

1058

over the pipeline by air, land or sea. Use of remotely

piloted aerial patrol drones can provide video or photo-

graphic features for pipeline right of way monitoring.

The use of satellite is also being considered in some

quarters. For pipelines in creeks, swamps and difficult

terrain and where the pipelines run into thousands of

kilometre, in a spaghetti network in mangrove trees and

creeks as in the Nigeria Niger Delta region, this method

becomes almost impossible.

3.3. Fibre Optics Systems

A project was initiated by the US department of Energy,

Office of Fossil Energy in this area in 2001 and the over-

all objective was to develop and demonstrate an optical

fiber intrusion detection device that would prevent out-

side force damage by detecting and alarming when con-

struction equipment is near the pipeline vicinity [16].

The principle used in this project was that when heavy

equipment comes into the right of way, it compresses the

soil and creates vibration which changes the dynamics of

the light and reflects the changes to the source. Field

testing of the basic concept has been proved. However,

according to the report of the project close-out, the sensi-

tivity of the technique needs substantial improvement to

be practiced in the industry [8]. This project was cham-

pion by Gas Technology Institute (GTI).

A similar product developed by Future Fibre Tech-

nology (FFT) differs by sending continuous signal in-

stead of pulse light. Their system has also three sensing

fibre strands instead of one strand used in the GTI pro-

ject. Two fibre strands measure the changes in the mo-

tion, sound or vibration while the third delivers informa-

tion to determine location of the event. This tool is cur-

rently being used in Europe and USA [8]. Both systems

however require the fibre to be installed along and close

vicinity to the pipeline

3.4. The Impressed Alternating Cycle Current

(IACC)

This is a kind of pipeline monitoring method consisting

of impressing electrical signals on the pipe by generating

a time-varying voltage between the pipe and the soil at

periodic locations where pipeline access is available. The

signal voltage between the pipe and ground is monitored

continuously at receiving stations located some distance

away. Third party contact to the pipe that breaks thro ugh

the coating changes the signal received at the receiving

stations. Based on information recently found in pub-

lished studies, it is believed that the operation of IACC

on a pipeline will cause no interference with CP systems

[17]. Initial results on operating pipelines showed that

IACC signals could be successfully propagated over a

distance of 3.5 miles (5.63 km), and that simulated con-

tact can be detected up to a distance of 1.4 miles (2.4

km), depending on the pipeline and soil conditions [17].

This method will allow existing pipelines to be retrofit-

ted for monitoring without excavation because the tech-

nique uses existing cathodic protection (CP) test points.

In addition, the method could be readily applied to new

pipelines.

Huebler, (2002) gave the benefits and drawbacks of

the technologies especially for pipeline right of way in-

trusion detection [10], many of which are presented in

Table 2.

4. Discussion

The application of the acoustic methods in the manner of

the most recent technology may require modifications for

use in submerged steel pipelines and manifolds where

attack or encroachment on a pipeline is not through the

act of “digging or ground breaking”. Verification of per-

formance of the acoustic method in submerged pipeline

is yet to be documented. An experience to trace acoustic

transmission on water pipeline at depth of 12 m suggest

that it would not pose a bigger challenge and may even

prove to be easier than land based pipelines. This ex-

perience conforms to the work of Muggleton and Bren-

nan (2004) on the sound attenuation in plastic pipelines

submerged in water. They found that energy does not, in

fact, radiate into the water and the attenuation is small

compared with that for a pipe buried in soil [18].

In managing the noise level in acoustic methods, it

could be possible to study sound generated from a given

pipeline and identify the anomalies that could occur in

the form of act of digging, cutting, ho t tapping and drill-

ing. And then concentrate on monitoring deviation from

“normal” noise levels as a measure of control. This sug-

gestion is relevant because most of the trunk and trans-

mission pipelines on land are located alongside motor-

able roads from where most noise could be generated.

(Using fibre optics in this scenario would lead to a lot of

noise generation). The oil field stations in the region are

not too distant from each other. The implication is that

the acoustic and alternating current attenuation may be

managed by localising the monitoring system to closest

station as possible and identifying the “normal” condi-

tions.

Pipeline networks in most oilfields in the Niger Delta

of Nigeria are more or less “spaghetti” in swamps and

shallow water. Unfortunately, the networks of pipelines

are often the small flow lines in the range of 4 inch to

8inch running from various points and sometimes cross-

ing each other. Use of acoustics and fibre optics methods

for these small diameter pipelines for detection of in-

tended and unintended damages would be technically

and financially cumbersome. New method or combina-

tions of me t hods wo ul d therefore be req ui red.

Pipeline Potential Leak Detection Technologies: A s sessment and Perspective in the Nigeria Niger Delta Region

1059

Table 2. Benefits and draw bac ks of the tec hnologies.

Comparison of different technologies

SN Technology Benefits Drawback

1 Satellite monitoring at visible wavelengths. No equipment to install on ground. Uses

commercial satellites. Possible replacement

for weekly flyovers of pipelines.

Requires sunlight. Affected by cl oud co ve r. A

method is needed to pick out acti vi ty over narrow

pipeline in broad image

2 Satellite monitoring at several wavelengths. Could detect encroachment at night an d

through cloud cover.

Requires more than one satellite. A method is

needed to pick out activity over narrow pipeline in

broad image.

3 Ground-based visual surveillance. Can use commercially available cameras.

System is needed to minimize the amount of

human monitoring. May not see directional boring

encroachment. Separate camera needed for each

line-of-sight.

4 GPS system and computerized pipeline

maps. No equipment installed on pipeline.

Requires equipment on each piece of construction

equipment. Requires equipment operators to

maintain equipment. Restricted use in right of way

monitoring.

5 The impressed alternating cycle current

(IACC). Continuous monitoring. Could be u sed in

conjunction with acoustic det e ct i o n .

Detects rather than prevents damage. Requires

breaking of coating for detection. Requires

minimum breaks in pipeline coating.

6 Acoustic detection of impacts.

Continuous monitoring. Localized

installation of sensors. Could be used in

conjunction with cathodic prot ec ti o n

detection.

Detects rather than prevents damage. Sensors

attached to outside pipe wall. Only one chance to

detect transient signal. Issues of background noise

must be solved. May be too costly if close sensor

spacing is required.

7 Distributed optical fibe r with

interferometr-ic detection. Continuous m on i t o ring. Sam e for m factor as

pipeline. Sensitive technique

Continuous fiber must be installed along pipeline.

Methods are needed to distinguish hazardous and

benign encroachment . Detects changes to the entire

fiber cannot distinguish simultaneous events or

events plus benign encroachment.

8 Distributed optical fiber with optical time

domain reflectometry.

Potential to monitor miles of pipeline from

each location.Continuous monitoring. Same

form factor as pipeline. Can detect and

distinguish simultaneous events at different

points along optical fiber.

Continuous fiber must be installed along pipeline.

Methods are needed to distinguish hazardous and

benign encroachment.

*Part-sourced from [11].

Figure 2 is a map of major oil and gas p ipelines in the

Niger Delta. The sum of oil and gas pipelines in the

Western and Eastern regions is indeed a congested field.

So far, it appears that the best proposal could be a

combination of Impressed Alternating Cycle Current

(IACC) and the Acoustic methods. The IACC would be

employed in the short and congested relatively smaller

diameter lines. The acoustic would be used for longer

transmission, trunk and distribution lines. Further im-

provement in terms of cost and effectiveness however, is

required for the acoustic system.

Directional drilling HDD pipe laying equipment was

recently used to lay a gas pipeline 45 metres beneath the

1.7 km Escravos River [19]. This approach has been felt

in different quarters to be the future oil and gas pipeline

installation to end the pipeline vandalism and illegal oil

bunkering in the oil industry in the Niger Delta region

[20].

The technology seems attractive for new pipelines,

especially long distance pipelines, but the attendant pipe-

line maintenance issues and over-burden problems re-

main a concern, especially in the future.

5. Conclusions

This section has, in summary term, attempted to discuss

the complex and diverse subject of leaks and potential

leak detection. The oil theft and pollution in the Niger

Delta region have shown an increasing trend over the

years and the consequence of technology and research

not growing to cover the challenges posed by these could

further complicate the social, economic and environ-

mental concerns in this region.

There is indeed a growing need for potential leak de-

tection technologies in the area of intended and unin-

tended pipeline damages in the Nigeria Niger Delta as in

many other part of the world. In proposing a combination

of IACC and an acoustic system in this region, it is

hoped that efforts would be made to test the integration

Pipeline Potential Leak Detection Technologies: A s sessment and Perspective in the Nigeria Niger Delta Region

1060

Figure 2. A Map of Nigerian Niger Delta showing some oil

fields and pipelines (Source: Urhobo Historical Society,

http://www.waado.org/nigerdelta/Maps/Oilfields.html, As-

sessed 26.07.2011).

and workability in terms of cost and effectiveness.

6. Acknowledgements

One does express his gratitude to AS Norske SHELL fo r

provision of fund for the research studies in the area of

oil/gas leak detection technologies. I also acknowledge

the efforts of the Prof. Gudmestad O. T., for taken time

to review and suggest improvement to this review work.

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