Cl02 Water Conditioning

Background

Chlorine dioxide is an oxidizing biocide that has been used for municipal water disinfection in the United States since the 1940’s. It is also used in the food industry as a direct food contact and incidental food additive status sanitizer and disinfectant for the vegetable, meat, dairy, and fresh pack sectors. The benefits for the use of chlorine dioxide in these industries are that chlorine dioxide provides superior penetration into biomass combined with superior microbial elimination, while also preventing the formation of undesirable disinfection by-products such as THM’s from chlorine or bleach and bromates from ozone or hydrogen peroxide. Unlike alternative technologies, chlorine dioxide is a true gas that is a relatively stable oxidant, reacting only with reduced compounds such as sulfides, phenols, and biomass.

Frac on the Fly Treatment (FOF)

We utilize a slip-stream technique, where a portion of the water in the main line headed to frac is pulled through a manifold into the generation unit. A ClO2 concentration of a few hundred to a maximum of 3,000 ppm ClO2 is then generated into the water and pushed back through the same manifold into the main water line where it is diluted to its desired concentration on the way to the frac tanks. The desired concentrations in the frac tanks typically ranges from 5 to 10ppm and concentrations in the blender/ hydration unit typically range from 1 to 3ppm. These can be readily measured on-site with iodometric titration methods.

Produced water Recycling

Certain properties of produced water make its reuse in fracturing problematic unless first treated to mitigate these characteristics. Specifically, produced water often contains high levels of dissolved ferrous iron (Fe2+) which has the potential to cause significant operational issues downhole if used in fracturing and hinders other fracturing chemistry. Produced water also contains significant amounts of valuable residual oil that is forever lost if used in fracturing without first being removed via treatment.
Chlorine dioxide is extremely effective in reclaiming and reusing produced water, particularly when used in conjunction with other complementary mechanical processes.
This process eliminates water handling costs such as hauling water, disposing of produced water, and the need to buy fresh water to complete the fracturing project. It can also lower chemical costs for the fracturing project such as friction reducer (FR). By allowing more efficient hydration of the FR, less is needed to achieve the desired affects.

Downhole Treatment

Eliminates Iron Sulfide

Iron sulfide plugging in the near-wellbore area is a widely recognized cause of decreased well productivity. Unlike conventional acidization, which only temporarily solubilizes iron sulfide deposits through the introduction of low pH hydrochloric acid, Downhole solution completely dissolves iron sulfide and converts it to water-soluble iron sulfate. Any biofilm buildup will also be eliminated by the chlorine dioxide treatment.

In addition to increasing performance of oil and gas field wells, Downhole CIO2 treatment process also:

Enhances worksite safety by oxidizing any potentially dangerous H2S gas present in the near-wellbore area that might otherwise escape to the atmosphere. Reduces equipment damage by creating conditions within the well that are conducive to smooth operation.

Provides a chemical tool that can be used to “unstick” process equipment such as submersible and rod pumps, thereby reducing dependence on workover rigs to maintain operations.