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IMPROVING THE SAFETY OF MARINE PIPELINES 1 Introduction The safety of marine pipelines is a timely topic for assessment. New public concerns about the integrity of this vital network—carrying one-fourth of the nation's gas production and one-ninth of its oil —were raised by several dramatic accidents in the late 1980s, involving loss of life and heavy property damage (Chapter 2). These events drew sharp attention to the offshore industry's aging pipeline infrastructure, its move toward deeper water, the recent entry of many small pipeline operators (some without extensive experience or large financial resources) and other developments, which have led owners, regulators, and others to ask whether the operational practices and standards that evolved over the past 40 years are adequate today. Hurricane Andrew, in September 1992, by closing down much of the marine pipeline network for weeks, brought home the economic cost of interruptions, and the vital importance of assured safety for the long term. More than 20,000 miles of large- and medium-diameter marine pipelines, some dating from the 1950s, lace the coastal waters of the United States. Nearly all are in the Gulf of Mexico; a few hundred miles lie off Southern California, and a few miles of pipelines are in the state waters of Alabama and Alaska. Most are off the coast of Louisiana, which accounts for about 90 percent of the nation's offshore oil and gas production; nearly all the rest are divided between Texas and California (Lindstedt et al., 1991). The federal waters of the outer continental shelf (OCS) contain nearly 17,000 miles of pipeline. State waters—within the 3-mile limit (in Texas 3 marine leagues, or just over 10 miles)—have perhaps 5,000 miles more (personal communication, James Thomas, Office of Pipeline Safety, July 7, 1993). The total mileage of marine pipelines increases by a few hundred miles each year, with new additions nearly balanced by abandonments. The offshore pipeline industry, since its first ventures into the shallow coastal waters of the Gulf of Mexico and the Pacific in the early 1950s, has steadily improved its operating practices, with new materials, more robust designs, and more efficient techniques for construction, operation, and maintenance. Today it operates with confidence in waters as deep as 1,700 feet and has developed the technology for much deeper waters, up to perhaps 3,000 feet. It has longer term plans for depths of perhaps 6,000 feet. Figure 1-1 and Figure 1-2 show production trends for the OCS.
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IMPROVING THE SAFETY OF MARINE PIPELINES FIGURE 1-1 Offshore crude oil and gas condensate production in federal waters, 1954–1991. FIGURE 1-2 Offshore natural gas production in federal waters, 1954 –1991. DIVIDED REGULATORY RESPONSIBILITIES Safety regulation of marine pipelines is shared by federal and state agencies. On the OCS, the Office of Pipeline Safety (OPS) of the U.S. Department of Transportation regulates nearly 13,000 miles of so-called transmission pipelines (generally the larger, longer pipelines that carry oil and gas ashore), and the Minerals Management Service (MMS) of the U.S. Department of the Interior about 4,000 miles of production pipelines (those associated with production and initial processing). In state waters, OPS has jurisdiction over transmission pipelines, and the states over production pipelines. OPS may certify state agencies to carry out enforcement of OPS regulations on intrastate transmission pipelines in state waters; agencies in Louisiana, Texas, Alabama, and California are thus certified. (States may have additional or more stringent requirements as long as they
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IMPROVING THE SAFETY OF MARINE PIPELINES FIGURE 1-3 Pipeline safety regulatory jurisdictions in federal outer continental shelf waters. are compatible with OPS requirements.) Figure 1-3 is a schematic drawing of the jurisdictional boundaries between the two agencies. MMS has broad regulatory authority beyond its immediate concern with production pipelines. Under the Outer Continental Shelf Lands Act (43 U.S.C. 1334), it issues permits and rights-of-way for all OCS activities, including pipelines, to ensure “maximum environmental protection by utilization of the best available and safest technologies . . . taking into account, among other things, conservation and the prevention of waste.” MMS is responsible for ensuring that pipelines are installed, maintained, and operated in compliance with permits. In pursuit of this goal, the agency sometimes establishes requirements for OPS-regulated pipelines that originate on the OCS. The Oil Pollution Act of 1990 (P.L. 101-380) will further expand MMS's authority over pipeline operations. The act, implemented by Presidential Executive Order 12777 (October 1991), makes the agency responsible for ensuring spill prevention and response capability for all marine pipelines, including those in state waters, which are regulated by OPS or the states for safety purposes. Regulations to implement the act, through cooperative agreements between MMS and the states, are being prepared. Other federal, state, and local agencies have their own responsibilities. The U.S.
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IMPROVING THE SAFETY OF MARINE PIPELINES Army Corps of Engineers issues permits for pipeline crossings of waterways, shorelines, and navigation fairways. The U.S. Coast Guard regulates navigation generally, and may declare pipelines hazards to navigation. The Coast Guard also conducts annual safety inspections of ports, including pressure-tests of pipelines, and may close facilities that fail to meet its standards. State and local agencies issue permits for coastal activities, in accordance with their coastal zone management plans. SAFETY CONCERNS Marine pipelines operate in a physically and technically demanding environment. They are subject to severe weather, shifting sediments (especially in some areas of the Gulf), and a constant threat of corrosion. In California they also face seismic risks. New pipelines are being installed in deeper waters, farther offshore, where the large gas and oil discoveries have been made, but where operation and maintenance present even greater challenges (Figure 1-4). The costs of inspection, maintenance, and repair are also generally far greater than on shore. The rapid growth in the number of firms operating marine pipelines has also caused some concern, because many are new entrants who have assumed control of major operators' older and less profitable pipelines in hopes of lowering operating costs. Today there are about 170 pipeline operating companies in the Gulf, up from about 65 a decade ago. It is essential that attempts to cut costs not interfere with adequate pipeline maintenance and safety. At the same time, all pipeline operators must contend with new regulatory costs, notably those entailed in the new standards for controlling oil pollution under the Oil Pollution Act of 1990. Pipelines also must share the seabed and waters with vessels of all types, near some of the most heavily used cargo ports in the nation and some of the most productive commercial and recreational fisheries. The potential for interference with other users was underscored in the late 1980s by two fatal accidents in which fishing boats operating in shallow waters struck inadequately buried pipelines, with ensuing explosions, injuries, and deaths (Joint Task Force on Offshore Pipelines, 1990; National Transportation Safety Board, 1990). A more general concern is pipeline damage caused by anchors and fishing gear. Oil field service and supply boats are a particular concern near platforms, where their maneuvering threatens pipeline risers and their anchoring can damage pipelines on the seabed. In addition, hurricanes, mudslides, and other natural forces can damage pipelines or cause them to fail. Oil spills from storms can be limited by shutting down and evacuating the platforms and pipelines. Still, disruption of this portion of the nation's energy supply for days or weeks is costly. The ongoing shift of production to deeper waters will increase the need for attention to safety. Much of the existing offshore pipeline infrastructure—and particularly the transmission pipelines—will remain in service, carrying hydrocarbons from the new deeper fields. Deep water pipelines are relatively inaccessible to workers, and they operate at low temperatures, which encourage the formation of corrosive brines, icelike gas hydrates, and waxes; the resulting inspection and maintenance problems will require new and innovative solutions. These trends have led the industry and its safety regulators to reexamine their approach to ensuring safety. They are asking fundamental questions:
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IMPROVING THE SAFETY OF MARINE PIPELINES FIGURE 1-4 Offshore production areas in the Gulf of Mexico, showing active and proposed federal leases.
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IMPROVING THE SAFETY OF MARINE PIPELINES What are the risks, and are they growing? Is maintenance technology keeping pace with the aging of the pipelines? Are today's inspection and repair techniques suitable for the new deep water pipelines? Are the measures taken to avoid interactions of pipelines with fishing vessels, cargo vessels, offshore supply and service boats, and recreational boats adequate? Do oil spill prevention and response requirements harmonize with the regulations to ensure personnel safety and protection of property? Do the industry and its regulators collect the right data to support decisions about risk abatement? SCOPE OF THE STUDY In considering these questions, this committee .has limited its scope to the risks to human safety, environmental quality, and property associated with pipeline failures. Accidents and oil spills due to activities of drilling and production platforms are outside the committee 's charge, as are the occupational risks of routine pipeline operations and maintenance. The committee has concentrated its assessment on the Gulf of Mexico, which contains the vast bulk of offshore pipelines. Conditions in California the committee agreed, are so different from those in the Gulf of Mexico, in size, in history, and in geology, that it is difficult to generalize. The California oil fields are small in geographical extent. Their geological setting includes the risk of earthquakes. Development of the offshore fields there has been relatively recent, and has been regulated strictly by the state and federal authorities, with drilling limited and pipeline installation and maintenance subject to more thorough environmental oversight. Statistical studies of the national data on pipeline failures, for these reasons, cannot be considered representative of conditions in California. The committee has noted several specific features of California's offshore pipeline system and its operation, maintenance, and regulation that offer useful comparisons with the Gulf. The committee excluded from consideration pipelines in harbors and waterways as well as those related to refinery and storage facility interconnections. Pipelines in Alaskan state waters were also excluded, in view of the special climate conditions and technical issues such as ice protection, which are unique to operations off the North Slope and in Cook Inlet. INADEQUATE SAFETY DATA Unfortunately, trends in the safety of marine pipelines are impossible to discern clearly, because the data are incomplete and unreliable. The several public agencies that regulate the industry have varied missions. Their individual efforts to investigate failures have not led to the development of a comprehensive safety data base. Data are collected inconsistently, without a well-thought-out or coordinated plan, and without a consistent focus on safety planning. Reports are often incomplete or inconclusive. Risk management on the basis of such limited information is challenging. The Marine Board of the National Research Council, in an effort to improve the factual basis for safety planning, commissioned the most complete study yet of the available data on pipeline failures on the outer continental shelf (OCS), drawing on the 1967-
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IMPROVING THE SAFETY OF MARINE PIPELINES 1990 pipeline failure records of the MMS, the OPS, and the U.S. Coast Guard's National Response Center, for 1,047 incidents in all (Woodson, 1991). This study reveals some important broad patterns. First, most damage to marine pipelines results in relatively small leaks of oil or gas, which may pollute the ocean and shore but are not serious threats to human safety. Pipeline oil spills of more than 50 barrels are rare (Minerals Management Service, 1992). Injury or loss of life from pipeline damage is also rare, but not unknown. Natural gas pipelines in particular (about 70 percent of the offshore pipeline mileage) hold the potential for explosions. Several accidents in the late 1980s, involving natural gas explosions associated with pipeline damage, resulted in deaths, injuries, and substantial property damage (see Chapter 2). Corrosion, the reported cause of about half of the pipeline failures on the OCS between 1967 and 1990, generally produces small leaks. The resulting pollution—in the case of oil or gas condensate pipelines —averages about 13 barrels (or, if one excludes a single 5,000-barrel spill in 1973, about 6 barrels). Vessel groundings or damage by anchors, nets, and trawl boards, while less common, produced the vast majority of pollution, and occasionally injuries and deaths. More than 95 percent of the pipeline-related pollution on the OCS was due to such incidents. And more than 95 percent of that pollution (90 percent of all marine pipeline spills, by volume) was due to anchor damage. (A single 160,000-barrel spill in 1967, caused by an anchor drag, accounted for nearly two-thirds of the pipeline spills, by volume.) The data base does not lend itself to detailed statistical analysis, owing to the variability of data collection standards from agency to agency and over time, the lack of precise information on pipeline locations, and gaps in the record. Because the data base is limited to the OCS, it does not support analysis of incidents in state waters, which house older pipelines and those most exposed to damage from vessels and storms. Nor can it show trends over time in rates of pipeline failures from different causes. The locations of pipeline failures—which might reveal patterns in anchor damage or corrosion —cannot be assessed systematically. Relationships between failure rates and length of service or product carried cannot be established, although such information would be extremely valuable in safety planning and should be assigned a high priority in future risk assessment efforts. Assembling a more useful data base should have a high priority, but will take years. Meanwhile, modern risk analysis can guide the industry and its regulators in focusing their abatement efforts. Some of these techniques are outlined in Chapter 3 of this report. FINDINGS Operators and regulators are seeking better assurance of the safety and integrity of marine pipelines. The importance of the marine pipeline infrastructure to the nation's economy, and the potential human, environmental, and monetary costs of damage, make this effort vital. Safety concerns are not to be taken lightly. There are significant unknowns in the safety record, owing to inadequate data collection by regulatory agencies, and safety trends over time are simply not available. However, enough is known to support development of risk management measures, guided by quantitative risk assessment, which affect pipeline design and operations and safety regulations. This report lays the groundwork for taking such measures.
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IMPROVING THE SAFETY OF MARINE PIPELINES REFERENCES Joint Task Force on Offshore Pipelines. 1990. Joint Task Force Report on Offshore Pipelines. Washington, D.C.: U.S. Department of Transportation, Research and Special Programs Administration. Lewis, G., P. DeGruy, and L. Avery. 1993. Hurricane-damaged Gulf of Mexico pipeline repaired with cold forging. Oil and Gas Journal, May 3, pp. 55ff. Lindstedt, D. M., L. L. Nunn, J. C. Homes, Jr., and E. E. Willis. 1991. History of Oil and Gas Development in Coastal Louisiana. Report 7, Resource Information Series, Louisiana Geological Survey. Baton Rouge. 131 pp. Minerals Management Service. 1992. Accidents Associated with Oil and Gas Operations. OCS Report MMS 92-0058. Herndon, Virginia. National Transportation Safety Board. 1990. Pipeline Accident Report. The F/V Northumberland and Rupture of a Natural Gas Transmission Pipeline in the Gulf of Mexico Near Sabine Pass, Texas, October 3, 1989. Report PB90-916502 NTSB/PAR-90/02. Washington, D.C. Tubb, M. 1992. Industry efforts minimize Andrew's destruction. Ocean Industry, October , pp. 11ff. Woodson, R. D. 1991. A Critical Review of Offshore Pipeline Failures. Prepared for Marine Board, National Research Council. December 1.
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