Geosynthetic Containment System - Concrete Cover

LOCATION: West of Conklin, AB

TIMEFRAME: April – November 2009

SCOPE OF WORK: Earthworks, survey, piping, geosynthetic containment system, concrete cover

PROJECT PARTNERS Owner: Statoil Prime Contractor: IMV Construction General Contractor: Layfield

Challenge

Statoil is a Fortune 50 integrated oil and gas company with operations in over 40 countries. In 2007 the company acquired North American Oil Sands Corporation with over 1,100 square kilometers of oil sands leases in northern Alberta.

An important component on Statoil’s strategy is building an experimental Steam Assisted Gravity Drainage (SAGD) facility near Conklin, AB. The name of the facility is Leismer Commercial Demonstration Plant, located approximately 160 km south of Fort Mac Murray. This demonstration plant is an important field research and pilot project to test technology leading to reduction in the use of water and the emission of CO2 over conventional SAGD technology.

Part of the Leismer project required to build a 15,000 square meter Lime Sludge Pond. The pond is a double-lined system and is fully protected with a concrete cover. In early 2009, Statoil and IMV Construction, the prime contractor handling the project selected Layfield as the general contractor to build the Lime Sludge Pond given its technical expertise, vast experience in containment applications and competitive price. Layfield was concurrently completing two tank farm containment systems and a storm water pond for the Leismer facility and had already established a solid reputation for quality and professionalism.

Layfield was responsible for the complete containment project from the ground up. The scope of the project required Layfield to contract manage the earthworks, piping, installation of all geosynthetic layers, a top concrete cover layer (which was a 6 inch RCC floor), and a FABRIFORM (a double-layer, 100% nylon fabric form) to form the concrete on the slopes.

One of the main challenges of this project was that Layfield had a very small window of opportunity to construct the Lime Sludge Pond, before harsh winter conditions settled in the region. It was also very important for Statoil that the project was completed on budget and on time. Another challenge of this project is that Statoil decided to place the liner behind all the building structures in order to reduce penetrations in the liner, which required extensive coordination with other prime contractors.

Solution

Layfield lined the floor area of the pond, from the bottom up, with LP8E non-woven geotextile, 60 mil High Density Polyethylene (HDPE) secondary geomembrane, geonet drainage layer and 60 mil textured HDPE primary geomembrane. In order to reduce penetrations in the liner, Layfield placed the liner behind and below all building structures. Layfield placed a concrete cover for the Lime Sludge Pond so that Statoil personnel would be able to traffic the pond and de-sludge periodically with no concerns of damaging the liner system. Working on the top concrete cover layer, a 6 inch RCC floor

In order to ensure that the pond had no leaks before placing the concrete, Layfield performed an electrical leak location survey. The electrical leak location survey detects electrical paths through the liner caused by water or moisture migration through a discontinuity in the liner. If a discontinuity (either a leak or an electrical ground) is present in the liner, electrical current will flow through the discontinuity. Once that the leak detection system was concluded, Layfield completed all required repairs, then performed a static water test and collected the water in the leak detection system. After the water test was complete, Layfield placed the concrete and conducted a final water test, which met Action Leakage Rate guidelines from Alberta Environmental Protection. It took more than a week to perform the water tests, which were not originally scheduled, and Layfield doubled its crew size to still be able to complete the project on time.

Our QA/QC package included the earthworks, concrete, liner system, and survey control, which required Layfield to customize a comprehensive ITP (Inspection and Test Plan) for the project.

Results

Layfield completed construction of the Lime Sludge Pond on budget and before schedule. Given the challenges and tight schedule, IMV and Layfield worked very closely together to bring the project to a successful conclusion. Both Statoil and IMV Construction were very pleased with Layfield.

The Lime Sludge Pond will go into service on March 2010. The Leismer SAGD facility is expected to produce 20,000 barrels per day in 2010 and over 200,000 barrels per day by 2020.

Layfield offers design, installation, and maintenance of geomembranes, floating covers, and geosynthetics systems throughout the US and Canada. Layfield is a specialized contractor with the people, equipment, and experience needed to install environmental protection systems for all geosynthetic applications.

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