Analysis of Human Reliability in the Project of Nigerian Oil and Gas Long Distance Pipeline

Analysis of Human Reliability in the Project of Nigerian Oil and Gas Long Distance Pipeline

O. Kadiri¹ and Samuel Oluwaseun Lawal1, 2 Department of Electrical and Electronics Engineering, Federal Polytechnic, Offa, Kwara State, Nigeria. 1Groningen Biomolecular Sciences and Biotechnology Institute, Zernike Institute for Advanced Materials, University of Groningen, Nijenbourgh 7, 9747 AG Groningen, The Netherlands.

Authors’ contributions:

This work was carried out in collaboration between both authors. Both authors designed the study, performed the statistical analysis, wrote the protocol, and wrote the first draft of the manuscript and managed literature searches with the analyses of the study. Both authors read and approved the final manuscript.

Article Information:  DOI: 10.9734/BJAST/2016/24358. Received 16th January 2016


The project of Nigerian oil and gas long distance pipeline cannot be achieved without Human Effort. The oil pipelines are majorly made from steel or plastic tubes with inner diameter typically from 4 to 48 inches (100 to 1,220 mm). Most pipelines are typically buried at a depth of about 3 to 6 feet (0.91 to 1.83 m). In order to prevent pipes from impact, abrasion and corrosion, a variety of approaches are used. These can include wood lagging, (wood slats), concrete coating, rock shield, high-density polyethylene, imported sand padding, and padding machines.

This paper contains how reliable human effort is in achieving a successful project execution of oil and gas long distance pipeline in Nigeria. An overview of possible shortcomings as a result of adopting human effort in oil and gas long distance pipeline is also considered and the possible solutions to such shortcomings are enumerated.

Organizing good training, which is a solid skills base, and strong management are unique key to preventing failures in pipeline construction, but safety usually starts with good plan. It is recently noted that failures in oil and gas long distance pipeline construction do occur as a result of increase in theft, sabotage and terrorist attacks. Meanwhile, the best approach to reduce these failures is by prevention, since detection method will be difficult to curb it.

The major conclusion drawn from this is that, long distance pipeline construction will require more human effort for efficiency and timely completion.


Keywords: Human; Reliability; pipeline; Oil and gas.


Human Reliability is the degree of efficiency and effectiveness human effort can attain in achieving a desire goal. Pipelines are therefore an efficient means of energy transportation (such as fluids) over long distances, from production locations to the various selling points. The secure and constant operation of hydrocarbon pipelines requires the pipeline machinist to have the most up-to-date information to hand concerning the state of his pipeline. It is clear from a number of gathered information that the most common source of pipeline failure is third-party external damage, caused by activity such as ploughing of buried lines, or the impact of trawl gear against (unburied) sub-sea lines [1]. Furthermore, in many areas in the Niger Delta region of Nigeria, the effects of sabotage or vandalism must also be considered.

In locations where the pipeline is relatively inaccessible, the principle and theory of standby of visual inspection is not an easy option to implement, and great damage may go undetected for considerable periods of time. The continued operation of upstream oil and gas pipelines in these often rather inaccessible locations requires the ability to monitor the line condition remotely [2].

The main elements that constitute a pipeline system are the Initial Injection Station, Compressor/Pump Stations, Partial Delivery Station, Block Valve Stations, Regulator Stations and Final Delivery Station. In general, pipelines can be classified in three main categories depending on its main purpose, such as Gathering pipelines or Flow lines, Transportation Pipelines or Cross country pipelines and Distribution Pipelines [3]. All these facilities face several daily vandalisations as a result of lack of proper protection system by the operating companies.

However, there continues to be frequent and catastrophic pipeline failures around the world. What lessons can we learn from these failures? We are experiencing change in the oil and gas pipeline industry recently, ranging from the need to continue to transport our oil and gas through ageing assets, to a much better supervisory safety administration. Consequently, the care of today’s pipelines is dependent on not only their design and operation, but also their maintenance, and management. Hence, it needs to be emphasized that pipelines are not treacherous or unsafe, but their design, operation, and maintenance and management can make them unsafe. Recent failures in the USA have been followed by the publication of regulations and standards that formally require pipeline operators to ‘manage’ their pipeline’s integrity and have in place formal risk management plans that clearly mitigate and control risks.


A comprehensive study on various pipeline systems and how they could be employed for pipeline protection in Nigerian long distance pipeline were carried out.

However, handling a pipeline system, for an effective safety is an all round-the-clock, complex operation that involves continuous spotting. Hence, we need a highly reliable, simple and dependable way to give supervisory control over the pipeline systems. Also, this research implemented comparative study method which comprised obtaining data from past and present studies, government and non- government bodies and existing literature. This study relied on secondary data, the secondary data was obtained from The Nigerian National Petroleum Cooperation, U.S. EIA (United State Energy Information Administration, Health and Safety Executive (HSE), Special Committee on the Review of Petroleum Product Supply and Distribution (SCRPPSD), U. S. EPA (United State Environmental Protection Agency), Oil and Gas International (OGI), Published and Un-Published materials, Books, Newspapers, Conference and Seminar Papers, Journals and the internet. The data obtained was analyzed using numerical and descriptive method and from the analysis, logical conclusions and progressive presentation of facts from the data was obtained. Meanwhile, the analysis gives a clear picture of the problem and trends. Obtaining recent data proved difficult from 2008 to date. The causes of pipeline incidents data was obtained from 2000-2008, and the number of oil pipeline failures by location (state) and cause of spill, NNPC, 1999-2005 was also obtained, the data was analyzed using Excel statistical software and graphically presented.

In the course of carrying out this study, the case of estimating methods with detailed Human Failure Event modeling is adopted for Human Reliability Analysis; it is considered to be the most estimating methods, and most useful with respect to depicting the causes of the events.


3.1 Construction and Operation

First and foremost, Oil pipelines are made from steel or plastic tubes with inner diameter typically from 4 to 48 inches (100 to 1,220 mm), [4]. In some areas, a pipeline may have to cross water regions, such as small seas, straits and rivers. In many occasions, they are sited entirely on the seabed. Pipelines of such are referred to as “marine” pipelines (also, “submarine” or “offshore” pipelines). They are used mainly to carry oil or gas, but transportation of water is also imperative. Taking into account offshore projects, a distinction is made between a “flow-line” and a pipeline. The former is an intra-field pipeline, in the sense that it is used to join subsea wellhead, manifolds and the platform within a particular development field. The latter, sometimes referred to as an “export pipeline”, is used to convey the resource to shore. The edifice and maintenance of marine pipelines indicate logistical challenges that are different from those on-lands, mainly because of wave and current dynamics, along with other geo-hazards [5].

Conspicuously, most pipelines are typically buried at a depth of about 3 to 6 feet (0.91 to 1.83 m). In order to protect pipes from impact, abrasion, and corrosion, a variety of methods are used. These methods include wood lagging, concrete coating, rock-shield, high-density polyethylene, imported sand padding, and padding machines [4].

In general, crude oil contains varying amounts of paraffin wax and in colder climates wax buildup may occur within a pipeline. Usually these pipelines are inspected and eviscerated using pigging method, which is the practice of using devices known as “pigs” to perform various maintenance operations on a pipeline. These devices are also known as “scrapers” or “Go-devils”as the case maybe. “Smart pigs” (also known as “intelligent” or “intelligence” pigs) are used to detect anomalies or irregularities in the pipe such as dents, metal loss caused by corrosion, cracking or other mechanical damage [6]. Most of these devices are launched from pig-launcher locations and travel through the pipeline to be received at any other location down-stream, either cleaning wax deposits or material which may have accumulated inside the line or inspecting and recording the situation of the line.

In the case of natural gas, pipelines are constructed of carbon steel and vary in size from 2 to 60 inches (51 to 1,524 mm) in diameter, subject to the type of pipeline. The gas is pressurized by compressor stations and is odorless unless mixed with a mercaptan odorant where requested by a regulating body [5].

3.2 Categories of Pipelines

In wide-ranging, pipelines can be categorized into three classes depending on purpose:

3.2.1 Gathering pipelines class

This is typically group of smaller unified pipelines forming complex networks with the purpose of bringing crude oil or natural gas from several nearby wells to a treatment plant or processing facility. Looking at this class, pipelines are usually short- a couple of hundred meters, though with small diameters. An example of gathering system is sub-sea pipelines for collecting product from deep water production platforms.

3.2.2 Transportation pipelines class

This contains long pipes with large diameters, use mainly for moving or transporting products (oil, gas, refined products) between cities, countries and even continents. This process of transportation networks comprise several compressor stations in gas lines or pump stations for crude and multi-products pipelines.

3.2.3 Distribution pipelines class

This class composed of several interconnected pipelines which has small diameters. It is used to take the products to the final consumer (end user). It also contains feeder lines to distribute gas to homes and businesses downstream. Pipelines at terminals for distributing products to tanks and storage facilities are typical example of this class.

3.3 No Outline Available

Transportation oftTransportation of Oil and Gas Products

To move the oil and gas product over a long distance pipeline, human effort is highly required in other to foster a successful delivery of any of the end products. The petroleum products can be generally driven through pipelines by the use of centrifugal pumps. These pumps are commonly sited at the inventing station of the line and at 20 to 100 mile intervals lengthwise the stretch of the pipeline, respect to the pipeline design, topography and capacity requirements. Generally, most of these pumps are compelled by electric motors, although diesel engines or gas turbines may also be used. Some pipeline employees also use computers remotely to control the pumps and other aspects of pipeline operations. There are pipeline control rooms which utilize Supervisory Control And Data Acquisition (SCADA) systems that return real-time evidence or hint about the rate of flow, the pressure, the speed and other attributes [7] [8]. The duties of both the computers and trained operators are to evaluate the information continuously. Also the pipelines are operated and monitored throughout the year (365 days a year, 24/7). In conjunction with this, some instruments return real-time information about certain specifications of the product being shipped (in the case of shipping), the specific gravity, the flash point and the density. Taking for instance, the instrument can measure some of the information that is important to product quality maintenance.

3.4 The Place of Development and Planning in Long Distance Pipeline

In building a pipeline, the construction project do not only covers the civil engineering work to lay the pipeline and build the pump/compressor posts alone, but also covers all the work related to the installation of the field devices that will support distant operation.

There are stages involve in developing and building a pipeline as the pipeline is routed along what is known as a “right of way”. These stages are:

  1. This stage involves open season to define market interest: Sizable numbers of potential customers are given the opportunity to sign up for part of the new pipeline’s capacity rights. The duration for this stage lasts up to two months. Provided interest in the pipeline service is limited, the project will definitely not progress.
  2. Route Selection: This stage involves the selection of Route (right of way).
  3. The design of pipeline: The design of pipeline project allows it to take any form out of possible numbers of forms, which includes the construction of a new pipeline, the change of existing pipeline from one fuel type to another, or enhancements to facilities on a current pipeline route. This stage may take up to six months.
  4. Getting approval: The next stage after the design stage is finalized and the first pipeline customers have purchased their share of capacity, is that the project must be approved by the relevant regulatory agencies or bodies. This process can last up to 18 months, most especially for pipelines that involve multiple states.
  5. The route must be surveyed.
  6. The route must be cleared
  7. This stage involves trenching of Main Route and Crossings (roads, rail, other pipes, etc.)
  8. Installation stage. It involves pipes installation.
  9. The Installation of valves, intersections, and so on.
  10. Pipe and trench covering stage.
  11. Testing for reliability and efficiency: After the construction has been finalized, the new pipeline is then tested to ensure its structural reliability and efficiency. This stage includes, hydrostatic testing and line packing.

Furthermore, by taking into account a case study of Russia Long distance Pipeline, Russia has “Pipeline Troops” as part of the Rear Services, who are trained to construct and overhaul pipelines. The only country to have Pipeline Troops over long distance oil and gas pipeline transportation is Russia.

3.5 An Overview of the Oil and Gas Pipeline System in Nigeria

By virtue of economy, Nigeria is a country with a monocultural economy which depends seriously on the petroleum industry for existence. As a way of tracing records the petroleum industry or sector in Nigeria was launched (inaugurated) in 1956, as a result of first discovery of oil in Oloibiri, in the present-day Bayelsa State. Nigeria’s oil sector has now been developed into a vast domestic industrial infrastructure, consisting of more than 300 oil fields, 5 284 wells, 7 000 km of pipelines, ten export terminals, 22 petroleum storage depots, 275 flow stations, ten gas plants, four refineries, and massive liquefied natural gas (LNG) projects [9] [10].

As a means of enhancing the distribution of crude oil products from the oil-rich part of the Niger Delta to other parts of the country, a network of oil pipelines was fabricated to link some of the states at notable strategic locations. In view, the system comprises of multi-product pipelines and crude oil pipelines that move across the country and form a network that links the 22 petroleum storage depots, the four refineries at Port Harcourt, Kaduna and Warri; the off-shore terminals at Bonny and Escravos, and the jetties at Atlas Cove, Calabar, Okirika and Warri.

Here in Nigeria the Pipeline and Product Marketing Company (PPMC), a subdivision of the Nigerian National Petroleum Corporation (NNPC) makes use of this system of oil pipelines to convey crude oil to the refineries in Port Harcourt (I and II), Warri and Kaduna (the distance of about 719 km). There are another set of pipelines known as multi-product pipelines. These are used to move products from the refineries and import-receiving jetties to petroleum storage depots across the Nation. The storage infrastructure, which consists of 22 loading depots linked by pipelines of various diameters ranging from 6 to 18 inches, has combined installed capacities of 1 266 890 (PMS), 676 400 (DPK), 1 007 900 (AGO), and 740 000 (ATK) m3 tonnes [11].

In order to make sure that there is safety of all the pipelines across the country, the government acquired a 3.5 m wide right of way on each side of the pipelines before they were visibly laid, and all the pipes were buried a meter deep to avert any accident due to contact. It is recently discovered that the integrity and safety of this pipelines have been compromised by vandals who now continuously tap into this huge highway of the Nigeria’s wealth, by virtue of economy.

3.6 Human Reliability Analysis of Oil and Gas Long Distance Pipeline in Nigeria (Methods for Adoption)

There is necessity for Human Reliability Analysis (HRA) if long distance pipelines will be adopted in Nigeria oil and gas sector.

To start with, there are many varied methods of Human Reliability Analysis, with the Health and Safety Executive (HSE) highlighting over 72 separate tools in existence [12]. Within safety-critical processes, the broad goal of HRA tools (and related tools such as Probability Risk Analysis) is to build-up a picture of individual task-steps that constitute a procedure, and how these steps are completed [13] [14]. HRA may be conducted to originally map a set of tasks and score the nominal error-rate, or to assess the degree to which end-user task completion conforms to the authorized task procedure [15] [16] [17] [18]. HRA Data collection typically involves elements of Task Analysis (TA) and in some models Behavior Analysis (BA), and may consist of end-user task observation; structured interviews and self- report questionnaires [19] [20] [21] [22]. Data gathered is used to pinpoint human error, or potential ‘weak-spot’ opportunities for human-led risk throughout the task completion hierarchy.

Using Human Reliability Analysis in the petroleum context has no globally established requirement for Probabilistic Risk Assessment (PRA) in the petroleum sector. Taking PRA into account or simply analogous methods such as Quantitative Risk Assessment (QRA) or Total Risk Assessment (TRA), these seem to be order of the day in countries such as Norway [23] or the United Kingdom [12]. It also remains an emerging movement in the U.S. [24]. In most countries where PRAs exist in oil and gas pipelines sector, they have adopted the earlier versions of PRAs in the nuclear industry which primarily identified hardware failure risks.

For Nigerian oil and gas long distance pipeline project , most especially petroleum sector, there is need for the petroleum-centered Barrier and Operations Risk Analysis (BORA) HRA method [25] whose concentrations is on the breakdown of barriers designed as part of security in depth to avert accidents in oil and gas production services. These barriers, however, omit many of the Human Failure Events (HFEs) that can rapidly cause accidents at the oil and gas pipeline facility.

The adoption of Probabilistic Risk Assessments (PRAs) concentrated on pipeline barriers may take care of important originators of many types of accidents. A review of three available Quantitative Risk Assessments (QRAs) for oil and gas long distance pipeline setting up established only a very general coverage for Human Reliability Analysis. The Quantitative Risk Assessments proffered some very narrow specific treatment of Human Failure Events, and the overall treatment of Human Reliability Analysis or Assessment is small. These Quantitative Risk Assessments is totally different from the overall rates of incidents. Taking for instance, the rate of accidental collision of a shipping vessel with an offshore rig is produced as a frequency based on past data. This rate embraces all sources of error but fails to delineate the specific root sources or risk contributions that are traceable to human error. The uses of Human Reliability Analysis methods are considered to be the most estimating methods, and they are recommended to be adopted when actual data are not available for human error rates.

However, here in Nigeria it is quite impossible to determine in most cases the exact extent to which human errors add to the events of failures, since the data are only presented in cumulative form without causes indicated. In short, such data may be useful in preempting the frequency of events based on former data; they do not depict the causes of the events. As such, their utility in modeling the causes and in averting the relapse of events is severely imperfect. Meanwhile, the case of estimating methods with detailed Human Failure Event modeling are therefore most useful with respect to depicting the causes of the events. Additionally, the events modeled in the QRAs generally do not consider the opportunity for recovery actions that may correct an escalating event. Also, recovery actions are an essential component of Human Risk Assessments; they are also increasingly viewed as one of the unique contributions of resilience in the face of accidents, humans uniquely can recover from mishaps and remedy the situation even for untrained or unexampled events [26]. Such recovery actions should not be over-credited in an analysis, but they represent a significant but last-chance effort to save the installation and prevent severe damage, environmental impact, and loss of life. Interestingly, because new systems require a safety analysis prior to implementation, HRAs are being performed alongside human factors design reviews that are not part of the QRA or PRA [27]. Such standalone HRAs use task analysis techniques to derive the appropriate HFEs, a process that potentially generates HFEs that are incompatible with the level of analysis used in the PRAs [28]. Indeed, one of the emerging challenges with such an approach is the integration of the HRA with the QRA [29].

3.7 An Overview of Performance Shaping Factors in Oil and Gas Operation

The human performance in oil and gas pipeline sector can be influenced by diverse Human Factor variables, either physically or psychologically. The case of influencers may occur before or during a duty, for instance, sudden ambient noise such as an alarm-test may distract a worker when he is partway through a task-process, by contrast distraction may occur prior to beginning a task, such as being given a last minute deadline for another piece of work, ‘priming’ the user with distraction [30] [31] [32].

Further distraction contributors are: environmental changes, current physical health, age, attitudes, emotions, state of mind, and cognitive biases. Traditional Human Factors such as distraction, situation awareness, fatigue, high cognitive load and stress can also have a significant impact on task ability [32] [33].

3.8 Some Oil and Gas Accidents in Nigeria

Pipelines conveying flammable or explosive material, such as natural gas or oil, pose special safety concerns to the society.

As a result of many errors that could be termed as human errors, the following malady from several others erupted from oil and gas long distance pipeline.

  1. October 18, 1998: Jesse pipeline explosion. A petroleum pipeline exploded at Jesse on the Niger Delta in Nigeria, killing about 1,200 villagers, some of whom were scavenging gasoline.
  2. July 10, 2000: Another pipeline explosion close to the town of Jesse killed about 250 villagers.
  3. July 16, 2000: At least 100 villagers died as a result of a ruptured pipeline explosion in Warri.
  4. November 30, 2000: A leaking pipeline engulfed fire close to the fishing village of Ebute near Lagos, killing at least 60 people.
  5. June 19, 2003: A pipeline punctured by thieves exploded and claimed lives of about 125 villagers near Umuahia, Abia State.
  6. September 17, 2004: A pipeline punctured by thieves exploded and exterminated dozens of people in Lagos State.
  7. An occurrence of oil pipeline punctured by thieves in 2006 which exploded and killed 150 people at the Atlas Creek Island in Lagos State. (May 12, 2006)
  8. December 26, 2006: A destroyed oil pipeline exploded in Lagos. Up to 500 people may have been killed.
  9. May 16, 2008: There was pipeline explosion at Ijegun.
  10. October 9, 2009: Up to 80 people were burnt alive in the southern state of Anambra when a fuel tanker truck exploded.
  11. April 2, 2011: A fuel tanker overturned at an army check-point in the central state of Plateau, in which about 50 people died.
  12. July, 2012: About 100 people died when a Nigerian tanker engulfed fire.
  13. July 10, 2015: Eni Oil-Pipeline Explosion in Nigeria Kills 12, Injures 3 [34].

3.9 Some Possible Hazard in Nigerian Oil and Gas Long Distance Pipeline and Typical Remedies

Below are some of the inimical hazard that may ensue as a result of human activities and errors in Nigeria oil and gas long distance pipeline;

  1. Due to the solvent segment of dilbit typically comprises volatile aromatic like naptha and benzene, rationally fast carrier vaporization can be likely to follow an above-ground spill, ostensibly enabling timely intervention by leaving only a viscous residue that is slow to flow. The introduction of benzene and other volatile carbon-based compounds (collectively BTEX) to the underground environment compounds the threat posed by a pipeline leak. Benzene can cause many health problems and is carcinogenic with EPA Maximum Contaminant Level (MCL) set at 5μg/L for portable water.

Operative protocols to reduce exposure to petrochemical vapors are well-established, and oil spilled from the pipeline would be unlikely to reach the aquifer unless imperfect remedy was followed by the introduction of another carrier, such as series of torrential downpours).

The design of Keystone XL extension to be buried under four feet of soil, adequately hinder post-spill evaporation of the carrier fraction [35]. As a result of this, the notable diluent and bitumen will migrate at different rates, though liable on the temperature- and structure of the surrounding soils, but separation will take place more gradually as the aromatics verbose through sediment rather than through air.

  1. The exposure of livestock, mainly cattle, to benzene has been shown to cause many health concerns, such as neurotoxicity, fetal damage and deadly poisoning.

In short, the whole surface of an above-ground pipeline can be openly examined for material breach. Pooled petroleum is unambiguous, readily spotted, and indicates the location of required repairs. Due to the fact that the effectiveness of secluded scrutiny is limited by the cost of monitoring equipment, gaps between sensors and data that require interpretation, leaks in buried pipe are more likely to go undiscovered.

  1. Most pipeline developers do not always prioritize effective surveillance against leaks. However, buried pipes attract fewer complaints. They are prevented from extremes in ambient temperature, they are shielded from ultraviolet rays, and they are less exposed to photo deregulation. Mostly buried pipes are isolated from airborne debris, electrical storms, tornadoes, hurricanes, hails and acid rain etc. Buried pipes are protected from nesting birds, rutting mammals, and wayward buckshot. Also the buried pipe is less vulnerable to accident damage (e.g. automobile collisions) and less accessible to vandals, saboteurs and terrorists.

3.10 The Detection of Leakages

Considering the Nigerians oil and gas long distance pipeline, there is need for leakages detection system. Oil and gas pipelines are an important asset of the economic development of almost any country; it has been required either by government regulations or internal policies to ensure the safety of such assets, the masses and environment where the assets are residence.

In Nigeria, pipeline companies face government regulation, environmental constraints and social situations. Government regulations may define minimum staff to run the operation, operator training requirements, pipeline facilities, technology and applications required to ensure operational safety. For example, in the State of Washington it is mandatory for pipeline operators to be able to detect and locate leaks of 8 percent of maximum flow within fifteen minutes or less. Social factors also affect the operation of pipelines. In third world countries such as Nigeria, product theft is a great predicament for pipeline companies. Many unauthorized extractions in the middle of the pipeline are commonly detected. In case like this, the leakages detection levels should be under two percent of maximum flow, with a high expectation for location accuracy.

Various technologies and strategies have been implemented for monitoring pipelines, from physically walking the lines to satellite surveillance. The most common technology to protect pipelines from occasional leaks is Computational Pipeline Monitoring or CPM. This CPM takes information from the field related to pressures, flows, and temperatures to estimate the hydraulic behavior of the product being conveyed. Immediately the approximation or estimation is finished, the results are linked to other field references to detect the presence of an anomaly or unexpected situation, which may be related to a leak.

In a situation where a pipeline containing passes under a road or railway, it is usually enclosed in a protective casing. This casing is usually vented to the air to prevent the build-up of flammable gases or corrosive substances; also to allow the air inside the casing to be sampled to detect any leaks in the transportation lines.

3.11 Pipeline Maintenance Culture

In order to have sustainable pipelines the issue of maintenance is of great necessity. The maintenance of pipelines includes inspecting cathodic protection levels for the proper range, surveillance for construction, erosion, or leaks by foot, land vehicle, boat, or air, and running cleaning pigs, in case there is anything carried in the pipeline which may be corrosive.

In the United State (US), the pipeline maintenance guidelines are covered in Code of Federal Regulations (CFR) sections, 49 CFR 192 for natural gas pipelines, and 49 CFR 195 for petroleum liquid pipelines. However, the place of maintenance is highly significant in pipeline construction network.


As earlier said, there is necessity for Human Reliability Analysis (HRA) if long distance pipelines will be adopted in Nigeria oil and gas sector. In this study the case of estimating methods with detailed Human Failure Event modeling is adopted.

4.1 The Human Factors Found to Affect Safety

The following human factors are found to affect safety, namely organizational, group and individual factors.

4.1.1 Organizational factor

Here various factors may contribute to an increase in incidents and accidents, which include cost cutting programmes and the level of communication between worksites [21]. Also, following factors were found to classify between factories in terms of safety climate, which includes importance of safety training, effects of workplace, status of safety committee, status of safety officer, effect of safe conduct on promotion, level of risk at the workplace, management attitudes towards safety and effect of safe conduct on social status [21]. According to Gordon, [21], Kletz recommended four ways for organizations to learn from past experience, which are: recent and old accidents should be described in safety bulletins and discussed at safety meetings, standards and codes of practice should comprise notes on accidents which led to the recommendations, a ‘black book’ comprising reports of accidents with technical interest that have happened should be compulsory reading for all newcomers and for refreshing memories and accident information recovery and storage systems should be used as they cover a wealth of useful information; In summary, the literature indicates that the organizational climate is highly significant for a safe working setting, where assurance to safety by senior management at the strategic or policy levels, training, communication, a positive safety elevation strategy and learning from past experience are imperative elements.

4.1.2 Group factor

The interactions between members of a work group, and between individuals and their supervisors, have great potential to impact the safety of an installation. Also, management’s leadership, supervision and crew factors can affect safety [21]. This section describes group dynamics which can help to improved or reduced safety. There may also be some degree of connection between organizational and group factors with regard to style of the management. Therefore, the notion of team working is a hefty portion of working in the offshore oil industry because many operations are managed by crews, shifts and groups working together [21].

4.1.3 Individual factor

This factor includes evaluation of the optimization of the human-machine interface, competence of the individual, perceptual judgments, stress, health risk and motivation; also, the contribution of human error to the probability of accidents [21].

According to Gordon, 1998, a study by the Institute of Nuclear Power Operations showed that the indispensable causes of accidents in the nuclear industry include organizational, group and individual factors. These factors were further broken down into: deficient procedures or documentation, lack of knowledge or training, failure to follow procedures, deficient planning or scheduling, miscommunication, deficient supervision, policy problems, and others. Table 1 below shows the percentages ascribed to each of these factors.

According to this analysis, deficient procedures or documentation is found to be 43%, lack of knowledge or training to be18%, failure to follow procedures to be16%, deficient planning or scheduling to be10%, miscommunication to be 6%, deficient supervision to be 3%, policy problems to be 2%, other to be 2%. However, the result shows that at least 92% of the underlying causes of accidents were caused by human, only a small amount of the overall causes were really introduced by front-line personnel (that is to say, failure to follow procedures) and most patented in either maintenance-related activities or in bad choices taken within the organizational and managerial realms.

4.2 The Theories of Human Error

Human error was studied in some detail by industrial psychologists such as Reason, Hudson and Rasmussen whose findings suggest that by attempting to conquer, or at least know human error, its consequences could be reduced [21]. By virtue of Rasmussen’s theory of human performance, Reason categorized errors in terms of skill-based slips and lapses, rule-based mistakes and knowledge-based mistakes. Thus, at the skill-based level, distraction or obsession with another task can lead to slips and lapses where watching of the task fails. If error will occur at the rule-based or knowledge-based performance level, attention would not essentially have to move far from the problem. Problem solving failures may occur when the incorrect rule is applied or the person is not familiar with the problem [21].

Table 1. Representation of Sub-Factors affecting safety

S/NDescription of Sub-Factors affecting safety Percentage (%)
1Deficient procedures or documentation to43
2Lack of knowledge or training18
3Failure to follow procedures16
4Deficient planning or scheduling10
6Deficient supervision3
7Policy problems2

The error types used according to Reason are based on psychological theories and are aimed to describe errors in high risk industries. This error types are complex and would need considerable training to understand and use on a regular basis. In a more simplistic approach, Kontogiannis and Embrey summarized human errors into six categories which are action errors, retrieval errors, transmission errors, checking errors, diagnostic errors and decision errors [21]. Table 2 shows details of these human errors.

Looking at this categorization, the first two error categories, action and checking relate to Reason’s skill-based slips and lapses; retrieval and transmission errors relate to Reason’s rule-based mistakes; diagnostic and decision errors relate to Reason’s knowledge-based mistakes [21].

4.3 Causes of Oil Pipeline Failure in the Niger Delta area of Nigeria

According to Achebe et al., [36], Tables 3 and 4 below shows summary of various Causes of oil pipeline failure in the Niger Delta area of Nigeria. However, human error is one of the causes of this so called pipeline failure which usually lead to oil and gas accidents in the oil producing region of the country. The failures are mechanical failure – failure caused by construction, materials and structural; Corrosion – failure that arise from both internal and external menace; Operational failure – failure caused by system and human errors; Third party activity – failure that arise as a result of sabotage, accidental, incidental and acts of vandalism; Natural hazard – these are failure experienced in oil sector as a result of subsidence, flooding and others.

Fig. 1. Graph for factors affecting safety in percentage

Table 2. The various categories of human errors

S/NError typeDescription
1Action errorsThese errors occur where no action is taken, the wrong action is taken or the correct action is taken but on the wrong object.
2Retrieval errorsErrors that occur when information that is required is not available, or the wrong information is received
3Transmission errorsThis is another type of errors which occur when information has to be passed onto someone else, either no information is sent, the wrong information is sent, or it is sent to the wrong place.
4Checking errorsThese are when the checks are omitted, the wrong checks are made or the correct check is made on the wrong object
5Diagnostic errorsIn a situation when an abnormal event arises, the actual situation is misinterpreted
6Decision errorsThese occur when the circumstances were considered but the wrong decision is made

Table 4 shows number of oil pipeline failures by location (State) and cause of spill in the Niger Delta Region of Nigeria. The total number of spills caused by mechanical failure across the six states is observed to be 23, corrosion is 21, operational failure (system and human) is 17, third-party activity is 28, Natural hazard is 3 and that of the unknown activities is 43.


Fig. 2. Distribution of causes of oil pipeline failures in the NDS, 1999-2005

(Source: Pipeline Oil Spill Prevention and Remediation in NDS, NNPC, 2007)

The relevant data on each of the oil pipeline failures are summarized in Tables 3 and 4. The causes of spills were analyzed in accordance with the internationally accepted nomenclature [37]. Operational failure under which human failure or error falls is seen to be 17. When graphical analysis was made, it is observed to be taking 10% of the overall causes of pipeline failures. Others are mechanical failure 42%, Corrosion 18%, 3rd party activity 24% and natural hazards 6%.

Fig. 2 shows the graphical analysis of the causes of oil pipeline failures in the Niger Delta Area of Nigeria. In this graph operational failure caused by both system and human have 10% of the overall causes of pipeline failures. Others are mechanical failure 42%, Corrosion 18%, 3rd party activity 24% and natural hazards 6%.

4.4 Causes of Pipeline Accidents

The table below shows causes of serious pipeline incidents. In this table, pipeline incidents are caused by corrosion, excavation damage, human error, material failure, natural force damage, other outside force damage and all other unknown causes [1]. According to Baker, [1], mechanical damage is by its nature very complex. However, there are a myriad of ways in which a pipeline can be impaired, under circumstances that vary from location to location. Also a pipeline’s properties and condition, and therefore its susceptibility for damage, are resolute by the system’s construction, operation, and maintenance history.

Table 3. A Summary of the Various Causes of Oil Pipeline Failure in the Niger Delta Region of Nigeria









Construction, Material and StructuralInternal,





Malicious (Sabotage),

Incidental and acts of



Flooding and


(Source: Pipeline Oil Spill Prevention and Remediation in NDA, NNPC, 2007)

Table 4. Number of Oil Pipeline Failures by Location (State) and Cause of Spill, NNPC, 1999-2005

S/NLocationCause of SpillTotal by location








Total by cause23211728343137

– =Not available

(Source: Pipeline Oil Spill Prevention and Remediation in NDS, NNPC, 2007)

In a nutshell, mechanical damage impacts safety, the environment, and system reliability. The consequences can differ from immediate to delay and from minor to disastrous. Meanwhile, managing the menace of mechanical damage is equally complex [1].

Going by the overall analysis of this table, human error is observed to carry a notable percentage of pipeline accidents that occurred from 2000 to 2008. The best way to manage prospect damage is broadly acknowledged to be through prevention and mitigation strategies [1].

In Table 5, it can be seen sequentially from year 2000-2008 that for overall causes of serious pipeline incidents corrosion caused 8.1%, 7.5, 5.6%, 0.0%, 6.3%, 4.9%, 8.6%, 6.4% and 5.3% respectively; excavation damage caused 32.2%, 42.5%, 33.3%, 50.8%, 18.8%, 19.5%, 31.4%, 27.7% and 18.4% respectively; human error caused 6.5%, 7.5%, 13.9%, 6.6%, 12.5%, 5.7%, 4.3%, 7.9% and 18.4% respectively; material failure caused 11.3%, 2.5%, 11.1%, 8.2%, 10.4%, 2.4%, 2.9%, 2.1% and 5.3% respectively; natural force damage caused 4.8%, 7.5%, 0.0%, 4.9%, 12.5%, 4.9%, 2.9%, 2.1% and 2.6% respectively; other outside force damage caused 0.0%, 0.0%, 2.8%, 4.9%, 14.6%, 26.8%, 25.7%, 19.1% and 23.7% respectively; and all other causes caused 37.1%, 32.5%, 33.3%, 24.6%, 25.0%, 22.0%, 22.9%, 38.3% and 36.8% respectively.

Also in the Fig. 3 shows human error falls under other/unknown failure. The failure, though not all are as a result of human error has value below 10% (between 7-8 %), going by distribution of incidents by cause in European gas pipeline. Others include, external interference – 50%, corosion – beteen 15% to 16%, construction defect/material failure – between 17% to 18%, hot tab made by error – between 4% to 5% and ground movement – between 8% to 9%.

Table 5. Causes of Serious Pipeline Incidents – All pipeline Systems (PHMSA 2000-2008) (Leading Cause Category Highlighted)

Cause Category200020012002200320042005200620072008
Excavation Damage32.3%42.5%33.3%50.8%18.8%19.5%31.4%27.7%18.4%
Human Error6.5%7.5%13.9%6.6%12.5%19.5%5.7%4.3%7.9%
Material Failure11.3%2.5%11.1%8.2%10.4%2.4%2.9%2.1%5.3%
Natural force Damage4.8%7.5%0.0%4.9%12.5%4.9%2.9%2.1%2.6%
Other Outside Force Damage0.0%0.0%2.8%4.9%14.6%26.8%25.7%19.1%23.7%
All Other Causes37.1%32.5%33.3%24.6%25.0%22.0%22.9%38.3%36.8%
Total No. Incidents624036614841354738


Fig. 3. Distribution of Incidents by Cause in European Gas Pipeline, (7th EGIG Report 1970-2007, Doc. No. EGIG 08.TV-B.0502, December 2008)


Assessment of results generated in this study of analysis of human reliability in the project of Nigerian oil and gas long distance pipeline, including human factors, human error, causes of serious pipeline incidents and accidents, risk assessment of the environment from oil pipeline spills.

In Table 1 and Fig. 1, organizational, group and individual human factors that was found to affect safety were further broken into, deficient procedures or documentation which is found to be 43%, lack of knowledge or training which is found to be18%, failure to follow procedures which is found to be16%, deficient planning or scheduling which is found to be10%, miscommunication which is found to be 6%, deficient supervision which is found to be 3%, policy problems which is found to be 2%, and others which is found to be 2%. The result shows that at least 92% of the underlying causes of accidents were caused by human, only a small amount of the overall causes were really introduced by front-line personnel (that is to say, failure to follow procedures) and most patented in either maintenance-related activities or in bad choices taken within the organizational and managerial realms.

Also, in Table 2, different errors that resulted from human factors were found to be Action errors- where no action is taken, the wrong action is taken or the correct action is taken but on the wrong object; Retrieval errors – when information that is required is not available, or the wrong information is received; Transmission errors – when information has to be passed onto someone else, either no information is sent, the wrong information is sent, or it is sent to the wrong place; Checking errors – when the checks are omitted, the wrong checks are made or the correct check is made on the wrong object; Diagnostic errors – when an abnormal event arises, the actual situation is misinterpreted; and Decision errors – when the circumstances were considered but the wrong decision is made.

Table 3-4 and Fig. 2 present the number of spills, spill frequency expressed as kilometer-years, and the failure rate for each Niger Delta State between 1999 and 2005. In Bayelsa, Delta and Rivers, the number of oil pipeline failures is very limited. Looking at Akwa-lbom, Cross-River, and Edo state, few pipeline failures were reported. Moreover, the spill frequencies for these states are graphically represented by lightly colored bars in Fig. 2, since these frequencies are based on a statistical estimate of 0.7 failures (50 percent confidence in Poisson distribution for zero events). Meanwhile, Rivers state has a high pipeline failure rate. This could be due to good reporting of oil spills in the area. Though, one oil spill in Rivers state was identified as sabotage. Pipeline failure rate in Akwa-lbom is low. This could be due to poor recording of oil spills, newer pipelines, better quality of materials used, better maintenance, or less corrosive soil and lower human error. The failure rate atimes may due to teething troubles for new pipelines or wear-and-tear on old pipelines as a result of age of installation.

In Table 5, human error (among others which includes corrosion, excavation damage, material failure, natural force damage, other outside force damage and all other unknown causes of pipeline incidents) is observed to carry a notable percentage of pipeline accidents that occurred from 2000 to 2008.

Fig. 3 shows the distribution of incidents by Cause in European gas pipeline. Human error falls under other/unknown failure. The failure, though not all are as a result of human error has value below 10% (between 7-8 %), when going by distribution of incidents by cause in European gas pipeline.


The essence of this analysis is to consider how reliable human effort is in the project of Nigerian oil and gas long distance pipeline. The estimating methods with detailed Human Failure Event modeling adopted enables logical conclusions to be drawn and progressive presentation of facts. Thus, action errors, checking errors, decision errors, retrieval errors, transmission errors and diagnostic errors are associated with human factor (organizational, group and individual) that affect safety. Considering deficient procedures or documentation, lack of knowledge or training, failure to follow procedures, deficient planning scheduling, miscommunication, deficient supervision, policy problems and others; all these are posed as a result of human factor that affect safety, at least 92% of the underlying causes of accidents were caused by human, only a small amount of the overall causes were really introduced by front-line personnel (that is to say, failure to follow procedures) and most originated in either maintenance-related activities or in bad choices taken within the organizational and managerial realms.

Meanwhile, pipelines can be the target of vandalism, sabotage or even terrorist attacks. Considering during war, pipelines are often the target of military attacks, as destruction of pipelines can seriously disrupt enemy logistics. In the case of oil spills in Niger Delta State if Nigeria, pipeline failure rate are due to sabotage, age of the installation, corrosion, teething troubles of new pipelines and human error.

Hence, no matter how effective or reliable human efforts are, there will still be some defects known as human errors that resulted into failure rate of oil and gas pipeline in the country; by extension undermine productivity, efficiency and the nation’s economy. It is therefore advocated that there should be adoption of stringent measures that is aimed at improving surveillance of the long distance pipelines. There should be fighting against corruption and the entrenchment of good governance in the country’s oil sector. Human Efforts or Events are therefore highly applicable and needed in long distance pipeline construction for efficiency and timely completion.


Since oil pipeline sabotage and human errors pose serious intimidations to a country’s well-being, as it is evident in this presentation. Hence, following recommendations will help in curbing oil and gas pipeline sabotage; reduce human errors in all its form in Nigeria, and by extension help to improve human reliability in the project of Nigerian oil and gas long distance pipeline.

  1. Let oil pipelines integrity in Nigeria be treated as a national security issue. The government should therefore accordingly ensure effective protection and monitoring of the network of oil pipelines across the country. The establishment of a special pipeline policing and protection agency, as well as the use of technological gadget such as satellite tracking and closed-circuit television (CCTV) monitoring in strategic loading bays will help to achieve this.
  2. It is an issue of necessity that the implementation of the initiative between the NNPC and the Plymouth University in United Kingdom, targeted at mapping out approaches to ensure that crude oil coming from Nigeria onto the international oil market is fingerprinted, be adopted. These approaches would permit buyers to determine the legality of origin and physical appearance of the product before putting a price on it.
  3. A complete overhauling of the pipeline system is also necessary. The overhaul practice should go hand in hand with periodic integrity checks during the lifespan of pipelines and a complete clearing of all structures that lie within path of these pipelines.
  4. The Nigerian security agencies such as navy need to be supported with the necessary facilities and logistics to boost their efficiency in tracking the inflow of small arms, and fighting sea piracy and oil bunkering in Nigeria’s regional waters. There is need for the inclusion of capacity-building projects such as a maritime awareness capabilities programme designed to enable them use the latest patrol boats, such as defender class response boats, which would advance their ability to successfully arrest oil bunkers and militants.
  5. There should be proper documentation of all procedural events taking place in oil and gas pipeline industry. Workshops and seminars should be organized to improve technical know-how of all personnels in the oil and gas pipeline industry of the country.
  6. Planning scheduling will go a long way to improve human reliability in the Nigerian oil and gas pipeline. There should be maintenance-related activities and good choices/policies taken within the organizational and managerial realms of the oil and gas sector.
  7. The appropriate Human Reliability Analysis approach such as estimating methods with detailed Human Failure Event modeling, and stringent measures that is aimed at improving surveillance of the long distance pipelines should be adopted to ensure a sustainable long distance pipelines in Nigeria oil and gas industry.

Competing interests: Authors have declared that no competing interests exist.


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© 2016 Kadiri and Samuel; This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


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