Pipeline integrity: Enhanced decision support with GIS
Todd R. Porter,John Parsons, Monty Martin
Tuboscope Pipeline Services
2835 Holmes Road
Houston, TX 77051
www.tuboscope.com
Abstract
The Pipeline industry is realizing the significant value that GIS adds to their integrity management
programs. Programs are under development and refinement to improve the safety, efficiency, and
profitability of this energy transportation infrastructure through effective data integration, analysis, and
decision support methods. A case study is presented, showing such an implementation, using a large
regional gas transmission system in Western Canada, complete with experience, benefits and examples.
Introduction
The pipeline industry has responded to the growing concern for public safety, and subsequent OPS
Regulations and Rulemaking(s)1 that require integrity management programs. An integral part of these
programs, is the use of internal inspection (ILI) devices or “smart pigs” that measure and map geometric
and material anomalies. As well, given the large and diverse data sources available, a software platform is
required that effectively integrates, manages, and provides analysis for decision support. The goal is to
acquire, integrate, and analyze data in an efficient, comprehensive manner for informed decision making.
This approach provides an enabling process for risk and consequence modeling tasks.
Using ILI 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 defects. With the integration of
spatial and attribute information via a GIS
framework, consequence modeling and 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.
Figure 1. Combination In Line Inspection Tool
ILI of pipelines involves the collection, processing, and analysis of a 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 measurements units (INS), 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 provides a product line
component called TruView GIS, built to provide GIS synchronized connectivity to the companion
corrosion and mechanical damage analysis system TruView TM thus adding the geo-spatial element to the
integrity management solution.
Technology integration
The location / geometry ILI tools used in pipelines utilize a combination of technologies: GPS, INS, and
GIS Systems. These integrated geo-spatial capabilities take corrosion, deformation 3D geometry surveys to
a new level of analysis and accuracy. A combined ILI tool (as shown in Figure 1) provides these
component technologies in a single run, thus minimizing lost throughput, operator expense, and potential
risk. 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.
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.
