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The Papa Terra Oil field employed membrane & UV technology to provide potable water to contractors at the remote job site
Discovered in 2003, the Papa Terra Oil field is located 68 miles (110 kilometers) off the coast of Rio de Janeiro in the Atlantic Ocean at a depth of 3,937 ft (1,200 meters). It is located in the Campos Basin, which is Brazil’s most important oil-producing region. A joint venture of U.S.-based Chevron and one of South America’s largest energy companies is operating the field, which has a planned total daily capacity of 140,000 barrels of crude oil.
The key to the oil drilling and production processes is a tension leg wellhead platform (TLWP), which will give the partnership the ability to develop a subsea field with direct vertical access into the well bore. The TLWP includes dry trees, top tensioned risers and a tender assist drilling rig, which will support all the well drilling and workover activities as well as export the production to the floating production, storage and offloading unit.
Such projects present a significant challenge when it comes to the health and safety of the platform workers: how to efficiently provide potable water to contractors who are spending long work hours on a job site that is far from the mainland. FloaTEC, the TLWP’s engineering, procurement, construction and installation contractor, selected a combination reverse osmosis membrane desalination filtration system and ultraviolet disinfection system to provide potable water to the employees on the TLWP. Both systems were provided by Severn Trent Services. Equipment installation was completed in 2012 with commissioning scheduled for Q4 2013.
Membrane Filtration & UV Disinfection
The reverse osmosis system—the UAT Pure Pro Series seawater desalination membrane filtration system—is designed to treat seawater with 37,000 ppm of total dissolved solids at 25°C. The system has a feed seawater flow of 22.4 gal per mintute (gpm), a reject flow rate of 16.8 gpm and a product flow rate of 8,064 gal per day. The Pure Pro Series systems, which are available in a range of output capacities, produce fresh, treated water, free of particulate matter or contaminants from a seawater source.
The systems are easy to operate and are built to withstand the harsh offshore and marine environments. They are suitable for commercial, offshore and marine-specific applications and are a cost-effective means of consistently providing a source of fresh water—whether for drinking and other sanitary needs, equipment wash down, boiler makeup feed water, engine cooling or other requirements. The UAT Pure Pro system is manufactured with corrosion-resistant components, flexible controls and a variety of other standard features.
To prevent the formation of bacteria in the potable water storage tank, one option is to pump water continuously through the tank. The UV system utilized at the Papa Terra TLWP prevents the need for 24-hour-per-day pumping, saving energy and extending the life of the pumps. The UltraDynamics Series 8102-HIE ultraviolet system, which has been in use for more than two decades and has been proven effective in installations over a broad range of applications around the world. Each Series 8102-HIE system provides a dose of 30,000 to 400,000 microwatt seconds per square centimeter at a wavelength of 254nm ultraviolet energy for deactivation of microorganisms.
The UltraDynamics UV system utilizes low pressure, germicidal UV lamps positioned in a stainless steel chamber. Pure, fused quartz sleeves used to protect the lamps are manufactured to provide a maximum transmission of UV energy into the medium. The system’s power supply center is rated at (120 Vac, 50/60Hz) (240 Vac, 50/60Hz).
According to Karim Nesicolaci, commercial operations manager for Severn Trent Services’ membrane filtration div., “Severn Trent Services has a range of reliable potable water desalination systems specifically designed to serve the offshore oil industry, and they can be installed in classified areas. The systems are compact, heavy duty and are engineered and built with high quality components, pumps and filters to deliver maximum performance, minimum down time for service requirements and minimum power requirements.”
Karim Alberto Nesicolaci is commercial/business unit manager for Severn Trent Water Purification Inc. Nesicolaci can be reached at [email protected].