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1 Introduction T his chapter describes the study charge and scope, analytic approach, and report structure. STUDY CHARGE Section 16 of the Pipeline Safety, Regulatory Certainty, and Job Cre- ation Act of 2011 calls for the Secretary of Transportation to âcomplete a comprehensive review of hazardous liquid pipeline facility regulations to determine whether the regulations are sufficient to regulate pipeline facilities used for the transportation of diluted bitumen. In conduct- ing the review, the Secretary shall conduct an analysis of whether any increase in the risk of a release exists for pipeline facilities transporting diluted bitumen.â1 Bitumen is a dense and viscous form of petroleum that will flow through unheated pipelines only when it is diluted with lighter oils. At present, the source of bitumen supplied to refineries in North America is the oil sands region of Alberta, Canada. Bitumen from Canada has been diluted for pipeline transportation to the United States for more than 30 years, primarily to refineries located along the Great Lakes and elsewhere in the Midwest. Bitumen production and imports from Canada have grown during the past decade, and this traditional U.S. oil- processing market no longer has the capacity to refine all of the supply. Meanwhile, refineries on the Gulf Coast, which have traditionally pro- cessed South American and Mexican crude oils with properties similar to bitumen, have sought access to the heavy crude oils from Canada. To accommodate the Canadian imports as well as the growth in domestic âPublic Law 112-90, enacted January 3, 2012. 1 4
Introduction 5 crude oil production, the flow directions of several existing pipelines have been reversed, new transmission pipelines have been constructed, and additional pipeline capacity is planned. Within the U.S. Department of Transportation (DOT), the regulation of pipeline safety resides with the Pipeline and Hazardous Materials Safety Administration (PHMSA). The U.S. DOT has thus delegated to PHMSA the responsibility of determining whether pipelines transporting diluted bitumen have an increased risk of release. A determination of risk requires an assessment of both the likelihood and the consequences of a release. To inform its assessment of the former, PHMSA contracted with the National Research Council (NRC) to conduct the study documented in this report. Specifically, PHMSA asked NRC to convene a committee of experts in pipe- line operations; risk analysis; safety regulation; and chemical, materials, and corrosion engineering to âanalyze whether transportation of diluted bitumen by transmission pipeline has an increased likelihood of release compared with pipeline transportation of other crude oils.â PHMSA did not ask NRC to study the consequences of potential pipeline releases of diluted bitumen. The full statement of task (SOT) for the study is contained in BoxÂ 1-1. The SOT calls for a two-phase study, with the conduct of the second phase contingent on the outcome of the first. In the first phase, the study commit- tee is asked to examine whether shipments of diluted bitumen can affect transmission pipelines and their operations so as to increase the likelihood of release when compared with shipments of other crude oils transported by pipeline. In the potential second phaseâto be undertaken only in case of a finding of increased likelihoodâthe committee is asked to review fed- eral pipeline safety regulations to determine whether they are sufficient to mitigate an increased likelihood of release from diluted bitumen. If the committee does not find an increased likelihood of release or the infor- mation available is insufficient for a finding, the committee is expected to prepare a final report documenting the study approach and results. STUDY SCOPE The SOT makes reference to several terms that delineate the study scope and require explication. First, the SOT specifically requests an examina- tion of âtransmissionâ pipeline facilities. The pipelines in these facilities
6 Effects of Diluted Bitumen on Crude Oil Transmission Pipelines box 1-1 Statement of Task The committee will analyze whether transportation of diluted bitumen (dilbit) by transmission pipeline has an increased likelihood of release com- pared with pipeline transportation of other crude oils. Should the commit- tee conclude that an increased likelihood of release exists, it will review the federal hazardous liquid pipeline facility regulations to determine whether they are sufficient to mitigate the increased likelihood of release. In the first phase of the project, the committee will examine whether dilbit can affect transmission pipelines and their operations so as to create an increased likelihood of release when compared with other crude oils transported through pipelines. Should the committee conclude there is no increased likelihood of release or find there is insufficient information to reach such a conclusion, a second phase of the project will not be required and the committee will prepare a final report to the Office of Pipeline Safety (OPS) of the Pipeline and Hazardous Materials Safety Administration (PHMSA). This report may include recommendations for improving infor- mation to assess the likelihood of failure. Should the committee conclude there is an increased likelihood of release on the basis of dilbitâs effects on transmission pipelines and their operations, it will issue a brief Phase 1 report of its findings and then proceed to the sec- ond phase of the project to determine whether hazardous liquids pipeline regulations are sufficient to mitigate the increased likelihood of release. The committeeâs final report following completion of this second phase will con- tain the complete set of findings, conclusions, and recommendations of both project phases. contain large-capacity pipe, usually 20 inches or more in diameter, and generally transport fluids over long distances under relatively high pres- sure (400 to 1,400 pounds per square inch). Transmission facilities also contain storage tanks, pumping equipment, and piping within terminals. Gathering pipelines used for collecting crude oil from production fields do not transport diluted bitumen in the United States and are not part of this study. As used in the SOT, the term âdiluted bitumenâ does not define a single product composition or specific set of product or shipment properties.
Introduction 7 Blending bitumen with lighter oils to lower viscosity is the common method of transporting this form of petroleum by pipeline. The volume of bitumen in a pipeline shipment will vary with the diluent, as will the chemical and physical properties of the shipment. The Canadian diluted bitumen transported in transmission pipelines to the United States gen- erally contains 50 to 75 percent bitumen by volume, with light oils consti- tuting the remainder. These bitumen blends are the subject of this study. It is recognized that the source and composition of bitumen shipments may change depending on technological advances, diluent supplies, refinery demands, and other technical and economic developments. Finally, the SOT asks the committee to examine whether pipelines transporting diluted bitumen have a higher likelihood of release than pipelines transporting âother crude oils.â Accordingly, the aim of this study is to determine whether shipments of diluted bitumen have a release history or specific properties associated with pipeline failures that lie outside the range of experience and properties represented by the full spectrum of crude oils transported by pipeline in the United States. ANALYTIC APPROACH An assessment of release likelihood requires information on the potential sources of pipeline failure. PHMSA mandates the reporting of releases from U.S. transmission pipelines and categorizes each according to its immediate, or proximate, cause. Historically, about one-third of reported releases have involved corrosion damage (Figure 1-1). Other causes include outside force damage, such as an excavator striking a buried pipe, and faulty equipment, operator error, and deficiencies in welds and materials used in pipeline manufacturing and installation. The committee reviewed U.S. and Canadian data on reported pipeline releases. The review provided insight into the main causes of releases, but the incident statistics alone could not be used to determine whether pipelines are more likely to experience releases when they transport diluted bitumen than when they transport other crude oils. Few incident records contain information on the type of crude oil released in an inci- dent or document the properties of the shipments moved through the pipeline over time. Causal details are also limited. Incidents categorized as corrosion damage, for example, do not specify whether the damage
8 Effects of Diluted Bitumen on Crude Oil Transmission Pipelines Natural force Excavation damage damage 5% 5% Other outside force damage 2% External corrosion 7% Material, weld, and equipment failures 39% Internal corrosion 16% Unspecified Incorrect corrosion (mostly operations small incidents) Other causes 9% 11% 6% FIGURE 1-1 Causes of crude oil pipeline releases reported to PHMSA, 2002 to 2011. Source: Incident data provided to committee by PHMSA Office of Pipeline Safety during presentations on October 23, 2012 (http://onlinepubs.trb.org/onlinepubs/dilbit/Keener102312.pdf). occurred as a result of the action of microorganisms, in combination with stress cracking, or at sites of previous mechanical damage. Such detailed information is important in determining the causative role of the crude oils being transported in the pipeline, particularly for failures arising from cumulative and time-dependent degradation mechanisms such as corrosion and cracking. Having identified the main causes of pipeline releases, the commit- tee assessed each cause with respect to its potential to be affected by the chemical and physical properties of the transported crude oil. Consid- eration was given to specific shipment properties that can contribute to internal degradation, external degradation, and mechanical damage in pipelines. While the committee did not perform its own testing of crude oil shipments, information on many of the chemical and physical prop- erties of diluted bitumen and other crude oils was obtained from public
Introduction 9 websites and assay sheets. Additional information was obtained from a review of government reports and technical literature, queries of oil pro- ducers and pipeline operators, field visits, and inferences from secondary sources such as the maximum water and sediment content specified in pipeline tariffs. The committee then compared the relevant properties of diluted bitumen with the range of properties observed in other crude oils and looked for instances in which diluted bitumen fell outside or at an extreme end of the range. Recognizing the possibility that some pipeline operators may modify their operating and maintenance practices when they transport diluted bitumen, the committee asked operators about their procedures in trans- porting diluted bitumen and other crude oils. The committee looked for evidence of changes in standard procedures, including corrosion moni- toring and control practices, that could inadvertently make pipelines more susceptible to failure. REPORT ORGANIZATION The remainder of the report is organized into five chapters. Chapter 2 provides background on the transportation of crude oil by pipeline, including the main components of pipeline systems and common aspects of their operations and maintenance. Chapter 3 describes the produc- tion, properties, and pipeline transportation of diluted bitumen. Chap- ter 4 reviews pipeline incident data from the United States and Canada. The analyses of how the comparative properties of diluted bitumen and other crude oils pertain to sources of pipeline failure are carried out in Chapter 5. Chapter 6 summarizes the main discussion points from the preceding chapters and presents the study results. Appendix A contains the questionnaire developed for pipeline opera- tors and the responses. A brief description of the federal hazardous liquid pipeline regulations and PHMSA safety oversight is provided in Appen- dix B. Agendas from the information-gathering sessions of committee meetings are provided in Appendix C.