Increasing supply of oil and gas from unconventional reserves has reduced oil prices. This in turn has placed scrutiny on the costs of exploration and bringing new facilities into production. Oil and gas companies are out-sourcing these activities to highly efficient specialist contractors to reduce costs. Water storages for large volumes of water can add significantly to the regulatory, financial and construction liabilities of developing new sites.
In this project located at a remote site, the client had established a highly efficient development process that reduced project costs by up to 60 percent. To achieve this outcome a low cost, saline water storage servicing several satellites was required.
The contractor, Concept Environmental Services, designed a unique above ground water storage tank with minimal environmental impact to the site. The 110m diameter by 2.5m high tank utilizes pre-cast concrete wall panels interlocked into steel columns with the entire structure pre-stressed with tensioned cables. Layfield’s Enviro Liner 6030 geomembrane material was selected for the double lining of the 25 million litre tank due to the material’s excellent UV, weathering and chemical resistance and flexibility. A leak detection layer and monitoring system was incorporated into the design to guarantee no discharge to the environment in the event of a breach or damage to the primary liner. A unique ballasting system to keep the double liner system in place when the tank is dry was also developed.
A specialist lining sub-contractor pre-fabricated the Enviro Liner 6030 into large panels in a controlled, clean factory in preparation for rapid deployment on site. All tank components and the pre-fabricated liner panels were trucked to site and after simple site preparation (grubbing, leveling and compaction of natural ground) the tank structure was installed by the contractor. The lining sub-contractor then installed the large pre-fabricated panels in a pre-determined sequence, completing and testing the secondary liner before installation of the leak detection layer. The primary liner was installed in the same manner as the secondary liner. The liner system was secured to the top perimeter of the tank and a ballast system installed to keep the liners in place while the tank was empty.
The entire tank installation only took two weeks with the client extremely happy with the result. The rapid installation reduced the probability of weather related risks and also resulted in a significant reduction of costs associated with remote site accommodation. The construction and installation time was less than half that of comparable storage solutions for the capacity required.
The installation also proved the capability of very large diameter storage tanks.