European pipeline safety and integrity performance in 2017
01 July 2019
Concawe, the European pipeline safety and environmental monitoring organisation, has collected 47 years of spillage data on European cross-country oil pipelines. This article, based on selected sections of Concawe Report 3/19 - 'Statistical Summary of Reported Spillages in 2017', covers the performance of these pipelines in 2017.
At nearly 37,500 km the current inventory includes the majority of such pipelines in Europe, transporting some 720 million m3 per year of crude oil and oil products.
Product theft attempts continued to be the major cause of spills in 2017, although the total number (11) showed a sharp decline from previous years (60 in 2017, 87 in 2015).
Another two spillage incidents were reported in 2017, corresponding to 0.06 spillages per 1000 km of line, just over one third of the 5-year average and an order of magnitude below the long-term running average of 0.45, which has been steadily decreasing over the years from a value of 1.1 in the mid-70s. There were no fires, fatalities or injuries connected with these spills. Both incidents were due to operational errors.
Although there have been relatively few incidents due to third party activities (excluding theft), in recent years this category remains the main source of spillage incidents.
76 companies and agencies operating oil pipelines in Europe are currently listed for the Concawe annual survey. For 2017, the last year for which statistics are available, 62 operators provided information representing over 131 pipeline systems and a combined active length of 32,250 km. In addition, Concawe could confirm from reliable industry sources that five other operators (representing 1,259 km) did not suffer any spillages in 2017.
Although not accounted for in the throughput, traffic and in-line inspections data, the additional inventory has been taken into account in the spills statistics. The nine companies that did not report represent 102 km. The reported volume transported in 2017 was 720 Mm3 of crude oil and refined products, slightly lower than the 2016 figure. Total traffic volume in 2017 was about 128x109.m3.km.
2017 spillage incidents
Eleven spillages related to theft attempts (third party intentional) were reported, in sharp decline from the record figures reported in 2015 (87) and 2016 (60). This is a good result although it is still relatively high compared to historical levels: 28 theft-related spillage incidents were reported between 1971 and 2012, and as many as 230 since then.
Two non theft-related spillage incidents were reported, corresponding to 0.06 spillages per 1000 km of line. This is just over a third of the 5-year average and nearly an order of magnitude below the long-term running average of 0.46, which has been steadily decreasing over the years from a value of 1.1 in the mid 70s. There were no reported fires, fatalities or injuries connected with these spills.
Both reported spillages were the results of operational errors. Although there have been relatively few incidents due to third party activities (excluding theft), in recent years this category remains the main source of spillage incidents, after mechanical failure. After great progress during the first 20 years, the frequency of mechanical failures appeared to be on a slightly upward trend over the last decade, but this trend has been reversed in the last seven years.
When excluding theft events (for which the volume lost is unknown in most cases), the gross spillage volume was 33 m3 or 1 m3 per 1000 km of pipeline compared to the long-term average of 64 m3 per 1000 km of pipeline. 100% of that volume was recovered.
In 2017 a total of 116 sections covering a total of 14,702 km were inspected by at least one type of in-line inspection pig. Most inspection programmes involved the running of more than one type of pig in the same section, so that the total actual length inspected was less at 7066 km (21% of the inventory).
Overview of the main issues affecting pipeline integrity
1. Corrosion in hot pipelines: an historical problem now resolved
External corrosion in insulated pipelines transporting hot products has been a major issue in the past, particularly in the 70s and 80s with several failures reported in any one year. The problem was inherent to the design of these lines. Over time most such lines have been taken out of service (only 52 km remains today from a peak of over 1100 in the late 70s) and the issue disappeared with them, with only four cases recorded in the last 20 years.
Most European pipeline systems were built in the 60s and 70s. Whereas, in 1971, 70% of the pipelines in the inventory were 10 years old or less, by 2017 less than 3% were 10 years old or less and 67% were over 40 years old. Over the last two decades, operators and regulators became concerned that ageing lines may be increasingly prone to mechanical (e.g. metal fatigue) or corrosion-related failures.
The Concawe database provides some reassurance in this respect, showing that the long-term decreasing trend of the failure frequency for both mechanical and corrosion causes has continued in recent years. A spike in mechanical failures observed towards the end of the last decade caused some concern. A detailed analysis showed, however, that there was no correlation between metal fatigue failures and pipeline age. Over the last ten years the downward trend has resumed.
There is therefore no evidence that the ageing of the pipeline inventory implies a greater risk of loss of integrity.
The development of sophisticated integrity management and maintenance systems including the use of new techniques, such as internal inspection with inspection pigs, has doubtlessly played a role and hold out the prospect that pipelines can continue reliable operations for the foreseeable future. Concawe pipeline statistics, in particular those covering the mechanical and corrosion incidents, will continue to be used to monitor performance.
2. Accidental third-party interference: an on-going problem not fully resolved
Pipelines run, mostly underground, over long distances through diverse areas and are as such vulnerable to accidental damage caused by parties involved in digging, excavating and other earth moving activities.
All causes and third party accidental spillages
This has been an issue ever since underground pipelines were first laid. Several measures have been put in place and actions taken over the years, including marking, enhanced surveillance, regular contacts with landowners and civil contractors and, in some countries, the development of so-called “one-call systems” designed to encourage potential “excavators” to declare their intentions in advance. These measures have had only limited success and, although the frequency of related incidents has decreased following the general trend, accidental third-party interference remains one of the major causes of failure in the European network.
3. Product theft: a new threat being vigorously and successfully addressed
By the nature of their location and the fact that they transport valuable commodities, oil pipelines have always been a potential target for criminals, vandals or even terrorists. Up to the beginning on this decade, incidents involving any of the above were few and far between in Europe (less than one incident per year on average), mostly related to theft attempts and geographically concentrated in South-Eastern Europe.
From 2011, there was a gradual and sharp increase in the number of theft attempts culminating at 147 in 2015, 87 of which causing a spill. These occurred in several different countries across the continent, often with evidence of sophisticated criminal operations.
Beyond the potential loss of product and/or disturbance to operations, such interference with pipelines, which involve drilling through the pipeline to install a small-bore connection, can cause serious environmental damage and potentially injuries or even fatalities.
Faced with this serious new threat, operators reacted promptly, enhancing surveillance, improving leak detection system capabilities and increasing awareness of the problem with own staff and contractors. Relevant information was shared within Concawe and best practices established and disseminated.
These efforts have paid off and the trend was reversed with 112 events recorded in 2016 and 46 in 2017. Indications are that the downward trend continued in 2018 with a provisional total of 35 incidents. Nonetheless, the annual rate is still far above the long-term average, requiring continued focus and vigilance.
The Concawe report on which this summary is based covers the performance of pipelines in 2017 and a full historical perspective since 1971. The performance over the whole 47 years is analysed in various ways, including gross and net spillage volumes, and spillage causes grouped into five main categories: mechanical failure, operational, corrosion, natural hazard and third-party interference. The rate of inspections by in-line tools (inspection pigs) is also reported.