| Pipeline Risk Assessment Assists Safe Transportation of Energy Resources
By Linda Harrington Baker Eleven campers dead and a crater 86 feet long, 46 feet wide, and 25 feet deep. That was the result of a natural gas pipeline explosion that occurred in southeastern New Mexico on August 19, 2000.
In the wake of recent high-profile disasters such as this one, EarthData, an airborne mapping, remote sensing and geographic information services company, has partnered with GeoEngineers Inc., a geotechnical and environmental firm, to pioneer a pipeline risk-assessment program that assists the pipeline industry in safely transporting hydrocarbons, and detecting potential problems before they happen. In the process, they discovered that this risk assessment tool could do much more for pipeline planning, engineering, and management than just maintain the line.
 Segmented into three risk categories, the colored sections of this pipeline image depict where a geologic hazard could critically damage the structure. Red areas are high-risk, yellow are medium-risk, and blue are low-risk. This end product was created from a one-foot ground sample distance digital orthophoto, supported by a LIDAR digital elevation model. While safe transportation of energy resources is a top priority for the pipeline industry, managing the nation's 1.9-million-mile system - most of which lies beneath the ground - is difficult at best. Yet once a pipeline is built and buried, it cannot be ignored. Third-party damage, corrosion and geologic hazards all pose cumulative risks to a pipeline's integrity. Moreover, Congress has mandated the National Pipeline Mapping System to create and maintain up-to-date maps of the country's pipelines. Fuel is a necessary part of life. The public simply wants to be assured that these materials are being transported safely. This system serves as an ideal tool to support the pipeline industry's efforts in conjunction with existing technologies such as smart pigs and land surveys.
"We could see that pipeline operators needed a cost-effective way to manage routine maintenance more efficiently and to pinpoint and assess the risk of potential problems before they occur," said Patty Pringle-Roberts of EarthData, someone who has a professional background not only in mapping, but also in geology and the oil and gas industry. "Public trust is built around a pipeline operator's ability to transport oil and gas products in a safe and efficient manner, and we knew a customized geographic information system could boost that trust for pipeline operators."
GeoEngineers Inc. has a long history of working with pipeline companies. Richard Duncan, an associate located in the firm's office in Redmond, Wash., discovered EarthData through a web-site search for mapping companies that claim remote sensing capabilities. He believed that this technology could be of benefit to his clients. Duncan knew remote sensing was the answer. He was also interested in the ability of remote sensing to locate existing leaks and to identify geohazards, which could endanger the pipeline structure and its surrounding environment and community.
As a start, the two companies designed a 50-mile test project for a major oil and gas company. They employed a unique combination of remote sensors with leak-detection capability, coupled with engineering and environmental services, and added to cost-effective and comprehensive data collection methods, all of which served to deliver the necessary information ready for classification and interpretation.
The foundation of the system is airborne data collection. For this task, EarthData used airborne GPS, IMU, LIDAR, and thermal sensors to create a digital orthophoto map of the underground pipeline corridor and alignment. The thermal data helped determine the exact location of the underground line, while the LIDAR terrain data helped identify potential geohazards. In addition, EarthData used multispectral sensors to measure stress in nearby vegetation, and soil-moisture levels around the pipeline, for possible leak detection and wetland delineation.
Aerial photography was acquired using a 4000x4000 panchromatic digital camera. LIDAR was collected with better-than-one-meter vertical accuracy, and an average post spacing of three meters. The swath width of the LIDAR was matched to the footprint of the digital camera to map a corridor width of 1600 feet. An Inertial Measurement Unit (IMU) was used to record precise changes in position and orientation of the LIDAR scanner and digital camera at a rate of 50Hz. All exterior orientation was derived from the airborne GPS and IMU without employing any ground control.
The acquired thermal infrared imagery provided GeoEngineers Inc. with a non-destructive tool to locate thermal anomalies, such as pipeline leaks. The thermal scanner covered a swath width of 7200 feet and provided data with 1.5 GSD. Final deliverables included geo-registered digital black-and-white orthophotos at one-meter GSD, and a LIDAR-derived digital elevation model (DEM) with one-meter vertical accuracy.
Once EarthData finalized the mapping, GeoEngineers tied the spatially correct data sets to other pertinent information in a geographic information system (GIS). This information included as-built engineering drawings, facility records, and corrosion studies. The result was a fully integrated GIS to help pipeline operators better manage their day-to-day operations, and to aid in pipeline risk assessment. GeoEngineers then used the data to create a rating system along the length of the pipeline that would indicate corresponding levels of risk.
By modeling potential risks and consequences for the entire structure and its surrounding environment within the GIS, GeoEngineers was able to predict potential trouble spots. They also identified an existing fault zone and a historic landslide that lay within close proximity to the pipeline. "Without the LIDAR terrain data, the landslide area could have easily been missed. GeoEngineers concluded that heavy rainfall or a seismic event could reactivate these geohazards, posing a significant threat to the pipeline and the surrounding area," Pringle-Roberts said.
The client was impressed with the pilot project, and they have budgeted the funds to map the pipeline's remaining corridor in 2001. "Our standard product will be digital orthophotos from airborne GPS, IMU, LIDAR, and the digital camera," Pringle-Roberts said. "Thermal and possibly multispectral will be considered add-on services. This way, if the pipeline company initially wants only geologic hazard or high-consequence area data, we can always come back later and fly the other sensors if leaks are suspected."
GeoEngineers quickly realized the impact of this new product. "The potential for this technology is immense," Richard Duncan said. "Think of all the questions on a pipeline operator's mind. Where exactly is the pipeline, and how far is it from a school? What will happen in the event of an earthquake, a landslide, or a flood? Where are the nearest shut-off valves? Where should new valves be placed to best effect? Which segments of the line have the highest risk factors? Will the city water supply be affected by accidental leakage?" He added, "How much fuel could escape after shutdown? Will endangered species lose habitat if a gas line explodes in this location? The sheer magnitude of these questions helps illustrate the need for the GIS we have devised and its possibilities as a planning, design, engineering, management, and renovation tool."
The benefits to this knowledge are almost limitless. Open exchange of information between pipeline operators, emergency response teams, government agencies, and area residents increase public confidence and operator credibility. Operators' jobs can be prioritized. Companies are better equipped to comply with the demanding regulations set by the Transportation Department's Office of Pipeline Safety. And, most important, with the pipeline map at one's fingertips, guesswork about the exact location and integrity of the line is eliminated. Moreover, this information is just as useful for pipelines that lie above ground.
The system also facilitates the planning of new lines. In many ways, it is even harder to design a new pipeline and obtain all the environmental clearances than it is to build a new highway. With this system, EarthData and GeoEngineers offer planners and engineers more information than was previously possible regarding safe pipelines sites. As Pringle-Roberts says, the ideal option for the industry is to build the GIS system during initial construction so the data can be at the operator's fingertips for all operations and management.
As the public continues to question the integrity of the nation's pipeline systems, the industry strives to deliver fuel in the safest possible manner. The pipeline risk assessment tools developed by EarthData and GeoEngineers put the necessary information in the hands of the operators so they can better manage, maintain, and plan our nation's pipelines. About the Author
Linda Harrington Baker is director of marketing and communications for EarthData Holdings in Washington, D.C. She was formerly a vice president at Powell Tate, a Washington-based public relations firm, and also Washington correspondent for the Chicago Tribune. Back |
