Pipeline Safety: Inspection, Mapping & Visualization Methods

Pipeline Safety: Inspection, Mapping & Visualization Methods

Todd R. Porter
GeoSynergy Inc.
16225 Park Ten Place, Suite 805
Houston, TX 77084
Web: www.geosynergy.com

John Parsons
Tuboscope VETCO Pipeline Services
2835 Holmes Road
Houston, TX 77051
Web: www.tuboscope.com

Abstract
The pipeline industry has responded to the growing concern for public safety by developing a new family of in-pipe inspection tools called "PIGS" to measure and map geometric and material anomalies. From this data, numerous GIS map, profile, and pipe visualization views are constructed in a synchronized application framework. This approach provides a highly visual, multi-perspective presentation to assist in identification, location, and prioritization of potential pipeline anomalies. With the integration of spatial and attribute information via a GIS framework, a more comprehensive interface to risk assessment systems can be provided. This facilitates the most efficient and effective means to address pipeline operational safety. Examples will be presented showing the benefits of an integrated approach.

Introduction
Pipeline inspection involves the collection, processing, and analysis of gigabytes of data. These data volumes consist of measurements from many sensor types on the tool, with multiple channels, and at close spatial interval and high frequency. Typical measurement resolution is at 1/10" (2.5mm) longitudinal and 0.3" (8mm) circumferential for corrosion and internal deformation sensors, with channel counts reaching into the thousands for large diameter lines. This data along with inertial, velocity, and other internal detection sensors produces data sets approaching 100GB+ sizes, an enormous task to process, analyze, and prioritize without a streamlined and integrated system. Tuboscope has just released a product line component called TruPath, built by GeoSynergy to provide GIS synchronized connectivity to corrosion and mechanical damage analysis systems thus adding the geo-spatial element to the solution.

Figure 1a. Corrosion Inspection Tool

Figure 1b. Inertial Geometry Tool
Requirement
The following extract is a government perspective regarding pipeline safety, inspection, and public awareness. Although highly controversial with some parties in the pipeline arena, and subject to revision and approval, it underscores the importance of a comprehensive pipeline integrity plan, leveraging most current technical methods.

"Proposed legislation is underway to provide for enhanced safety and environmental protection in pipeline transportation, with particular emphasis in High Consequence areas. This proposed bill would reauthorize the U.S. Department of Transportation’s pipeline safety program, provide additional protections for critical areas, increase community knowledge about pipelines, improve investigation and enforcement authorities, support underground damage prevention, enhance the state role in interstate pipeline safety, and allow full compensation to states performing special investigations for the Department. This bill assures that pipeline operators are more accountable to the public for the risks they impose, that federal and state regulators have the tools they need to monitor that accountability, and that state and local authorities have the information they need to live safely with pipelines.

This proposal adopts an approach to critical areas--densely populated or unusually sensitive to environmental damage--that immediately benefits the public through emphasis on increased internal inspections and testing and a focused attention on pipeline integrity. Many pipeline operators are already adding protections for critical areas. This proposal provides the flexibility to continue those efforts. At the same time, this proposal would provide the needed incentive to those operators that have not moved quickly enough. It would give the Department enforcement and rulemaking authority to assure that critical areas receive the attention they need. Because of the importance of the issues, the Department is using existing regulatory authority to move forward to address increased protections for these critical areas and expects to publish the first of a series of rules this spring. The statutory authority requested would bolster this effort.

Recent experience indicates that communities need more information about pipelines. This proposal reinforces the ability of communities to know what pipelines are in the community, the risks they pose, and how to live safely with them. This proposal would enhance public education programs and increase the information available to community responders and planners. It would also include state emergency response commissions and local emergency planning committees established under the Emergency Planning and Community Right-To-Know Act within the mix of state and local authorities who interact with pipeline operators. Because of the importance of these issues, the Department has begun discussions with citizen groups and state and local organizations about the needs in this area and ways in which they can be met."

As this draft legislation states, significant emphasis has been given to inspection, data integration, analysis and presentation of this data to the community. The ability to consolidate and analyze this data in an expedient and accurate manner is the basis of this application framework presented.

Technology Integration
The location / geometry inspection tools used in pipelines utilize a combination of technologies: GPS, INS, and GIS Systems in combination with traditional sensor arrays. These integrated geo-spatial capabilities take corrosion and deformation surveys to a new level of analysis and accuracy. As a result, analysts have a more complete information resource for:

Detecting and characterizing pipe anomalies,
Pinpointing locations of interest, and •Profiling the pipeline environment.

By combining pipeline location (and features) and presenting this location, attributes, and anomalies with other information such as;

aerial photography
satellite imagery (multi-spectral),
landownership, easements, right-of-ways,
adjacent and intersecting pipeline and utility corridors,
population centers,
public and private facilities (schools, hospitals, etc.),
transporation routes,
ground cover classification,
soil type surveys,
digital elevation models,
rivers, lakes, drainage, irrigation canals,
environmental and special interest areas,

the analyst has a more complete picture. Combining this information provides a comprehensive "prioritizing" tool for response, repairs / maintenance planning and risk-management decision-making. GPS (Global Positioning System) survey methods provide the means to accurately position key "sparse" points along the pipeline. This provides the absolute coordinate reference for the subsequent INS in-pipe inspection operation. These surface points are spaced at varying intervals along the pipeline and directly above the pipe, ranging from 1km to 5km separation. During the actual inspection run AGM's (above ground markers) are placed at these locations that record a precise synchronized time tag of the tool passage. Later correlation of these time events with survey position, provide calibration for the INS, and a means to control and minimize position errors computed from the INS.

The INS (Inertial Navigation System) is the main sensor unit comprised of precision rate gyros (ring laser or fibre optic) and accelerometers (Q-Flex) mounted on orthogonal 3-D axes and measuring at 100Hz rates and higher. This gives the much needed resolution described earlier. The inherent error characteristics, thus resultant accuracy of the INS are time based. These error sources, the most dominant being gyro drift, and accelerometer biases, must be corrected on a continual basis. This is done using continuous velocity derived from the odometer wheels that make contact with the inside pipe wall. Using advanced Kalman Filtering, and empirical / optimal smoothing techniques, the INS error sources are controlled and accurate position and attitude information produced. Thus, high resolution, accurate 3D position is produced, along with pipeline curvature, which could not otherwise be provided by conventional methods.

The GIS (Geographic Information System) provides spatial analysis and visualization of the pipeline and surrounding area. This spatial mechanism integrates inspection and positioning data with layers of spatial information about the pipeline and environment, such as topography, population densities and aerial photos, in both a planimetric map view, and profile view.

Application Integration
In order to leverage these technologies, an effective integration is the key to successful implementation and utilization. Remember, the analyst must plow through possibly hundreds of miles of data at 1/10" resolution! Having the ability to detect, identify, and analyze only "anomalies", then prioritize them in an efficient and accurate manner is the objective. Therefore, these technologies must be tightly coupled and placed in an application framework that allows the user to configure for the optimal view perspective.

Figure 2. Pipeline MapView
Figure 2 presents a MapView within the application framework. This view is constructed using ESRI's MapObjects TM employing all theme, symbology, rendering, and display controls. As can be seen, the pipeline trajectory (at meter level position accuracy), along with multi-media themes, point themes, right-of- way theme, and backdrop aerial photography is presented for an effective location view.

Figure 3. Pipeline Profile View
The next view in Figure 3, shows the related elevation profile view of the pipeline. Any pipeline related them may be added to this view as in the MapView. A key aspect of the application integration is "synchronization". Any one of the views presented may be used as the navigation control. By clicking on a feature of interest, that pipeline "measure" (distance or stationing) is broadcast to all other applications which then update and display the exact location and view extents. This is a very powerful feature for the analyst; they can fly immediately to the next feature of interest. Note as well that other compliant applications, such as the corrosion analysis software are synchronized as well, providing a complete inspection view of the pipeline.

Figure 4. Attribute Profile View
The system architecture has been designed to display any inspection related attribute as shown in Figure 4. This includes geometry parameters such as; inside diameter, ovality, and curvature components. Shown above are the inertial attitude values for pitch, roll and yaw. Note that the tool completed almost four complete revolutions in this particular segment.

Figure 5. Feature List Navigation
Shown in Figure 5 is the feature list application, with a select file containing all detected girth welds on the pipeline. The ability to load any "measure" based feature list, enables the analyst to navigate accurately to; welds, anomalies, or any select feature. This navigator is open to send / receive "measure" reference. In full animation mode, the application framework can fly through the data completely hands-free.

Figures 6a and 6b show the color rendered perspective view of the pipeline from an open "slice" view and "axial" longitudinal view. The analyst has complete control of color classification of this internal shape data and controls to rotate, scale, and flip views to provide the best perspective on potential defects or anomalies.

Figure 6a. Slice Pipe View

Figure 6b. Axial Pipe View

Figure 7. Pipeline Corrosion View
Finally, the related and synchronized pipeline corrosion view is presented above in Figure 7. This application is the analysis tool used to identify and grade the internal and external defects of the pipe.

Conclusion
The integrated application framework presented utilizes GPS, INS, and GIS technologies to enable more comprehensive analysis of operating pipelines in the geo-spatial domain. An open architecture, and application synchronization provides ease of use for the analyst, and a resultant platform that provides interface to down stream risk analysis and maintenance planning. As discussed earlier, regulatory initiatives are underway that will require a geo-spatial reference frame for inspection, maintenance, and information dissemination. GIS provides an integral element in achieving that goal, and when coupled with materials inspection and other analysis tools, a more synergistic result is achieved.

References

Federal Register / Volume 65, No. 79 / Monday, April 24, 2000 / Proposed Rules
"Building Applications with MapObjects V2.0", ESRI, 1999, ESRI, Redlands, CA.