New computer approaches currently being developed by Argonne National Laboratory, Argonne, Ill., for the Gas Reasearch Institute, Chicago, will make planning a pipeline route easier and more cost effective by combining a wide variety of geographical data for a specific area, according to GRI.
The new approaches use currently available geographic information system (GIS) to store those data in digital form and present them in combinations of overlying "layers."
OBSTACLES
Planning the route of a new pipeline is not simply a matter of going from Point A to Point B. Between those two points may lie any number of obstacles.
The obvious barriers are the natural features of the landscape, such as lakes, rivers, mountain ranges, or unusual soil types. Other barriers are man-made: roads, population centers, and farmland.
Finally, because of increased environmental regulations affecting pipeline construction, even undeveloped areas may be difficult to traverse if they harbor endangered species or fragile ecosystems such as wetlands.
Judging the impact of these factors during siting of a pipeline right-of-way is difficult, says the GRI.
Currently, pipeline companies identify a likely route and then collect route data along the potential right-of-way from maps, field surveys, or other sources to determine what obstacles must be overcome.
Next, permit requirements to traverse the route are assessed. If the proposed route presents insurmountable physical obstacles, environmental constraints, or other barriers to permitting, a new route must be chosen and the data collection process begun again.
OPTIONS CONSULTED
Logic within the GIS software permits a wide variety of options for graphical display of geologic, hydrologic, environmental, and other mapped features. Route selection alternatives can then be displayed that include environmental and engineering cost factors.
The first step is to incorporate into the GIS digital data on physical and environmental features for the geographical area of interest. The GIS combines the data into layers that geographically represent the area.
Some examples of physical and environmental features that could be included are maps of surface features, soil types, bedrock depths, surface hydrology, endangered species ranges, and protected areas.
Next, costs associated with pipeline routing and construction are specified separately for the various features represented by the different layers.
For example, if the area has a shallow water table or unusual soil, the added engineering costs associated with that condition must be assigned accordingly. Costs may be actual costs, if known, or assigned on a relative basis with an arbitrary scale.
TIME, MONEY SAVINGS
Finally, the user selects combinations of data, and the model produces a least-cost right-of-way, or several alternatives, with respect to all of the different variables that may affect pipeline construction.
This new application of GIS technology could save the gas-pipeline industry both time and money in investigating new pipeline routes. Model results can be obtained before analyses of physical maps or a trip into the field to investigate alternative routes.
In addition, GRI says that regulatory acceptance of GIS models is growing rapidly, raising the prospects of speeding pipeline permits and expediting construction.
GRI expects to complete this project by yearend.
Copyright 1993 Oil & Gas Journal. All Rights Reserved.
