RESEARCH MAIN

American Petroleum Institute, Pipeline Variable Uncertainties and Their Effects on Leak Detectability (1993) - 00027

Now that almost all pipeline companies rely to some extent on computerized leak-detection systems known as supervisory control and data acquisition (SCADA) systems, this API technical report is useful as a reminder that the reliability of such systems is limited. Despite the industry's claims that companies can detect leaks and shut down pipelines instantly, this report notes the difficulties in detecting small leaks, especially those which leak one percent or less of volume being transported.

Association of Oil Pipe Lines

Corrosion Prevention in Pipelines (2002) http://www.aopl.org/pubs/2002/Corrosion%20Prevention%20Final%20Aug%2028.pdf

The one-page fact sheet briefly describes current industry practices of pipe coatings and cathodic protection to prevent corrosion.

Pipeline Integrity (2002) http://www.aopl.org/pubs/2002/Pipeline%20Integrity%20(detail)%20Final%20Aug%2028.pdf

This four-page fact sheet describes various industry practices to detect cracks, corrosion and other pipe flaws that can lead to pipeline spills and leaks.

The Environmental and Safety Programs of Oil Pipeline Companies: A Prevention Ethic (1999) http://www.aopl.org/pubs/misc/programs.pdf

While this 17-page public relations document exaggerates industry prevention measures, it provides some useful information, such as, the industry now estimates that a typical oil pipeline accidents costs the operator $1-4 million, but the average accident costs $10-15 million. Despite this, the industry opposes most pipeline safety proposals as too expensive for companies.

EFA Technologies Inc., Leak Detection on Petroleum Pipelines (1989) - 00062a

This brief paper surveys the various leak detection system methods, such as mass balance and transient modeling, and recommends using combinations of methods, depending on the characteristics of the pipeline.

Esso Chemical Canada, Tekscent, a Technological Breakthrough: A Pipeline Leak Detection Service (1991) - 00069

Developed in Canada, this system is appropriate for locating pinhole leaks in problem pipeline sections that other systems cannot locate. It uses a special odorant, which testers pump into the leaking section, then deploys trained dogs (Labrador Retrievers are a favorite) to sniff along the route and locate the surface scent caused by the leak. Gas chromatographs commonly used can detect scents that are one part per billion, but Tekscent-trained dogs can detect one part per billion-billions. Tekscent is not widely used in the U.S.

National Energy Board (Canada), Stress Corrosion Cracking on Canadian Oil and Gas Pipelines (1996) - 00036

This form of pipe defect begins on the outside of pipe as small cracks, invisible to the naked eye, in clusters that can grow and merge to weaken the steel and cause ruptures. This 158-page report details how this cracking happens and what can be done to prevent it from causing further pipeline accidents.

National Transportation Safety Board

Pipeline Safety Hearing: Inspection and Integrity Verification (2000) http://www.ntsb.gov/Events/2000/pipeline_hearing/trans001115.htm

This two-day hearing included numerous speakers and panelists who discussed in-line inspection technologies, integrity assessment methods, operator experiences and current research. The format that enabled NTSB members ask probing questions provides some interesting insights on pipeline safety.

Brittle-Like Cracking in Plastic Pipe for Gas Service (1998) - http://www.ntsb.gov/publictn/1998/SIR9801.pdf

This 55-page special investigative report concludes that the strength of plastic service pipes (from a gas main to a customer) is weaker than originally thought and may be a safety hazard as these pipes age and fail under pressure. These pipes were installed widely from the 1960s through the early 1980s.

NDE Environmental Corp., Rapid Leak Detection for Sea Floor Pipelines: Development of Practical New Methods (1990) - 00072b

This 23-page report shows how limited offshore pipeline leak detection systems are for even large spills, especially in shutting down and closing off pipelines that rupture. It notes that a large break (a six-inch hole) would probably take 10 minutes to an hour to detect and to shut down. In that time, 250,000 gallons could easily spill into the sea, and more would continue to spill before the break could be plugged. A smaller leak (a one-inch hole) could take up to two hours to detect, spilling 25,000 to 50,000 gallons.

Oil & Gas Journal

Study Tracks Internal-Corrosion Trends in Aging Gulf Pipelines (2000) - 00049

Corrosion of all kinds are the leading cause of leaks in aging offshore oil and gas pipelines in the Gulf of Mexico, and internal corrosion increasingly threatens these pipelines, especially in sags and low areas of piping where water and corrosive contaminants can settle. Factors include use of pipelines beyond their 20-year design life, new oil production fields in deeper, harsher areas, sales by major oil and gas companies of facilities to "smaller, untrained independent operators," and lower operations and maintenance budgets.

DOT Stats Indicate Need to Refocus Pipeline Accident Prevention (1999) - 00050

"The rate at which pipeline accidents occur shows no significant change over the last 16 years," the authors state, in analyzing OPS data from 1982 to 1997. They advocate special attention to reducing outside damage accidents, the measures including closer supervision of right-of-way excavations, better leak detection systems, and more pipeline markers. About the latter, they note that 68 percent of the outside damage accidents happened where no markers were in sight.

Alyeska Program Allows Pig Performance Comparison (1997) - 00064l

This technical paper discusses the experience of using smart pigs on the 800-mile Trans-Alaska Pipeline System to detect corrosion and cracks. One interesting finding is that the primary external corrosion problems were on the buried portion of the pipeline, not the aboveground portion.

Line Pressure Stress Affects MFL Signals (1996) - 00064k

This technical paper reviews the complex problems of using magnetic-flux leakage techniques by internal inspection device ("smart pigs") to detect corrosion-cause pits in buried pipelines.

ERW Line Pipe: Installed Pipe, Especially Pre-1970, Plagued by Problems and ERW Line Pipe: Pressure Management Key to Problematic ERW Pipe (1992) - 00064b

Despite the author's statement that "Evidence that inferior ERW [electronic resistance welded] pipe has been manufactured and installed, especially before 1970, abounds," replacing this extensively-use pipe is "impractical and undesirable." ERW pipe is especially susceptible to seam flaws. He recommends instead frequent hydrostatic testing, better record keeping of leaks and ruptures, and lower operating pressures.

Queens University (Kingston, Ontario), In-Line Inspection Tools for Pipelines (1997) - http://www.physics.queensu.ca/~amg/expertise/inline.html

This fact sheet provides readers with a succinct description and diagrams of how in-line inspection tools (or "smart pigs") work and what they look like.

Pipe Line & Gas Industry, Pacific Pipeline Designed With Latest Leak Detection Technology (1998) - 00067a

This technical paper discusses the leak detection and operator training techniques for a replacement pipeline transporting crude oil from near Bakersfield CA to El Segundo and Long Beach refineries. Because it traverses earthquake and landslide zones, hills, streams, and heavily populated areas, state and local officials required stringent protections from leaks and spills. The system installed relies on three redundant systems to distinguish between false and true alarms and to allow highly sensitive settings to detect small leaks. It also stresses intensive training of controllers to reduce the risks of operator errors, a common problem. Shutdown is aided by nearly 60 check and block valves on the 130-mile length ‚ far more than standard industry practice.

U.S. Department of Energy, Project Facts: Acoustic Detecting and Locating Gas Pipeline Infringement (2002) -

http://www.netl.doe.gov/publications/factsheets/project/Proj200.pdf

This two-age fact sheet describes a research project with West Virginia University to study the effectiveness of acoustic leak detection systems. The goal is to develop a centralized system to monitor background noise inside pipelines and detect the unique sound made when a pipeline break releases gas due to a sudden disturbance.

U.S. Environmental Protection Agency, Leak Detection and Leak Location in Underground Pipelines (1997) - 00125b

This brief technical paper describes the federal research effort to develop and test acoustic techniques to replace the less accurate, costly and time-consuming ‚ but commonly used ‚ volume and pressure leak detection methods.

U.S. Geological Survey, Rupture in South-Central Alaska ‚ The Denali Fault Earthquake of 2002 (2003) - http://geopubs.wr.usgs.gov/fact-sheet/fs014-03/

This fact sheet summarizes the effect of that earthquake on the Trans-Alaska Pipeline, which was only slightly damaged and did not rupture, averting what would have been a major oil spill in the Alaska Range. It concluded that the pipeline's design succeeded in preventing a major spill, but did not highlight the fact that the pipeline in the earthquake zone was aboveground, while pipelines in other earthquake-prone areas (such as Northridge CA during the 1994 earthquake there) are buried and unable to avoid rupturing.

U.S. Minerals Management Service, Survey of SCADA System Technology and Reliability in the Offshore Oil and Gas Industry (2000) - http://www.mms.gov/tarprojects/356/356AA.pdf

This 55-page report is a comprehensive survey of SCADA systems to assess on current state of the technology, its reliability, and recommended improvements. Because more operators of offshore platforms are beginning to operate them remotely from onshore centers, to cut costs, reliability will be more important than ever. The report noted that failure data are inadequate to make informed judgments about systems in use, and that operators refused to share their operational reliability information with researchers. 

U.S. Office of Pipeline Safety, How the Office of Pipeline Safety Utilizes In-Line Inspections(1996) - 00028

Delivered at the 1996 Pipeline Pigging Conference, this paper includes numerous case histories of the use of smart pigs after pipeline accidents to determine integrity of the pipeline before restarting operations. OPS used these experiences to justify using pigs instead of more reliable hydrostatic testing measure, despite the limitations of smart pigs. For example, the report states, "There is no single ILI [in-line inspection] tool presently available today that can consistently and accurately find gouges caused by mechanical equipment in dents."

Volpe National Transportation Systems Center, Remote Control Spill Reduction Technology: A Survey and Analysis of Applications for Liquid Pipeline Systems (1995) - 00067b

This 75-page study notes that supervisory control and data acquisition (SCADA) systems are increasingly used to detect oil pipeline leaks and spills, but that accuracy is limited by high false alarm rates (if systems are set to detect small leaks), failure to detect small leaks (if set to reduce false alarms), and untrained, inexperienced staff. Leak detection systems, such as liquid sensing cables buried next to pipelines, are more accurate, but much more expensive and not widely used.