Dow Brazil, through Dow Water & Process Solutions, its water treatment business unit, has just completed 20 years supplying water treatment solutions that have broken technological paradigms in the oil & gas industry. The treatment technology that makes use of selective nanofiltration membranes is used to remove sulfates from seawater to prevent scaling and souring in the reservoir. It is the use of SR90 nanofiltration membranes that allows the removal of sulfate to avoid scaling and assure productivity in oil reservoirs. 

For 50 years, Dow has been dedicated to supply technology-based innovations and solutions for a broad range of both industrial and residential needs. “Dow’s nanofiltration solutions are already a benchmark in the oil & gas industry in Latin America. Some years ago, other companies started to participate in this market with the opening of patents,” states Felipe Pinto, Marketing Manager for Reverse Osmosis and Nanofiltration technologies for the Americas for Dow Water & Process Solutions. 

According to Felipe, the Company offers a broad portfolio of chemical additives and expertise in filters for offshore applications, as in the case of Filmtec™ SR90 nanofiltration membranes used to purify seawater, which contains barium and strontium, substances that can precipitate with sulfate ions leading to scale formation, what compromises the reservoir productivity. Additionally, SR90 membranes offer a cost-effective and environmentally feasible technology for the removal of sulfate ions also present in seawater. 

Background 

Currently, more than 50 sulfate removal units are in operation, with more than 7.5 million barrels of water per day of cumulative injection capacity installed in the North Sea, the Gulf of Mexico, West Africa, and Brazil. The introduction stage from original idea to reaching growth mode in the early to mid-2000s took considerable time. The acceptance of the membranes and process technology by the oil & gas industry as a whole may have played a role in this relatively slow adoption, as well as the inherent cycle time from engineering stage to realization for offshore projects.

Several other factors contributed to the adoption of sulfate removal in the mainstream and establishment of membrane-treatment operation in the oil & gas industry. The increase of ultradeepwater production since the early 2000s, particularly in West Africa and Brazil, has driven the practice of removing sulfate at the source vs. using chemical routes to inhibit scale formation.

“Membrane technology itself continues to evolve and improve to meet the changing and ever evolving industry requirements, such as lower permeate sulfate levels and reduced weight and footprint. New membrane chemistries delivering increased rejection and higher flux have been brought to market, and module development enabled more surface area to be packed per unit of volume,” explains Kevin Reyntjens, Marketing Manager for the Oilfield Water division for Dow Chemical. 

Technology

Dow is the leading company in seawater sulfate removal technology using SR90 nanofiltration membranes. Deepwater drilling requires the use of water without sulfate and SR90 membranes are capable of assuring the level of sulfate in injection water below 20ppm in the polishing phase, thus significantly reducing the total system weight and space.