Saint-Flavien Site

Pointe-du-Lac Site | Saint-Flavien Site

The Saint-Flavien storage site, commissioned in 1998, is located 40 km southwest of Quebec City near Laurier-Station, some 10 km south of Highway 20.

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After optimization work, the working capacity at Saint-Flavien rose from 24 106m3 in 1988 to 120 106m3 in 2008, and the site’s potential is estimated at more than 142 106m3

Nature of the Site

The Saint-Flavien reservoir is located at a depth of around 1,500 meters in a geological zone that was overthrust when the Appalachians were formed some 440 million years ago during Taconian orogeny. It is composed of dolomite that formed there around 470 million years ago and is part of the Beekmantown formation. It is covered by nonporous carbonate, which serves as cap rock. The reservoir’s thickness ranges from 1 to 8 meters, with porosity ranging from 2.5% to over 10% but on average between 3% and 5%. The porosity is of secondary origin, which means that preexisting porosity was improved by way of hydrothermal fluids and fracturing.

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Cut-Away View

Cut-Away View


As shown, vertical and horizontal drilling of the geological structure is clearly visible at the Saint-Flavien site.


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Site Capacity

The Saint-Flavien site provides seasonal storage with a very good peak shaving capacity. The site’s storage size allows it to support elevated withdrawal rates over long periods. The following table shows the site’s specifications.

Working capacity 120 000 103m3 4.2 Bcf
Max. withdrawal rate 1 930 103m3/d 68.2 MMcfd
Max. injection rate 900 103m3/d 31.9 MMcfd


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Main Site Components

The Saint-Flavien site is very geologically complex. The following equipment is used for injection and withdrawal:

  • 11 injection/withdrawal wells, including 6 wells with horizontal drains totalling nearly 8 km
  • 4 observation wells
  • 4 km of gathering/injection lines
  • 24 km of high pressure pipeline linking the storage site to the TQM Pipeline facilities in Saint-Nicolas
  • 2 natural gas powered compressors: 1,600 CV and 2,400 CV
  • Gas dehydration and dewatering equipment
  • Heating and natural gas decompression equipment
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Site Process

During injection, gas coming from the TQM Pipeline is first filtered and compressed before being transferred to the wells by a gathering system. At each well, the gas is measured and injected into the reservoir. 


During withdrawal, the pressure differential between the reservoir and gas pipeline moves the gas out of each well. A methanol injection system located at the wells prevents hydrates from forming in the gas pipe. The gas is then transferred over the same gathering system, heated, decompressed to the required pressure, and dehydrated prior to reentering the pipeline tying the site to the TQM Pipeline system. Compression is used for about 60 days during withdrawal season.



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