The Ozonix® process attacks bacteria through a multi-phased oxidative treatment. First, ozone is injected into the fluid stream as the primary oxidant. Ozone is a strong oxidant that destroys microbial cell walls. In addition to ozone injection, hydrodynamic and acoustic cavitation are used to assist in destroying bacteria biofilms and segmenting bacteria colonies. This provides greater surface area for oxidation to occur.
Once an ozone molecule oxidizes a bacteria cell it leaves behind oxygen (O2) in the fluid. This oxygen then passes through an electrical and ultrasonic field creating highly reactive hydroxyl radicals. Hydroxyl radicals continue to react with organic material in the water. The electrical field itself is a strong oxidizer, breaking down and destroying bacteria cell walls. Chlorides and bromides form hypochlorite and hypobromite during this process. These compounds continue to assist microbial control in the fluid long after initial treatment.
The following bacteria results were taken over a three-year period while FNES was treating a mixture of fresh water and flow-back/produced fluid an average of 45/55 ratios at 100 barrels per minute. Compilations of 776 samples were taken on 282 wells during this time frame. The upper limits for tests performed were 1,100,000 MPN/mL; therefore influent averages potentially could be magnitudes greater. Each sample was taken just prior to our system and just after our system. The samples were analyzed using Standard Method 9221 serial dilution method at American Interplex Laboratories in Little Rock, AR. The bacteria totals are three-year averages of the total most probable numbers per milliliter of sulfate-reducing bacteria and acid-producing bacteria.
The Ozonix® process inhibits scale through electrochemical precipitation. The oxidation reaction takes place at the anode, which is positively charged, and the reduction reaction takes place at the cathode, which is negatively charged. Divalent cations combine with CO2 and SO2 generated from the oxidation of organic material.
These precipitated hardness salts are then broken into smaller particles in the process and passed through the system. These salt particles are chemically inert, suspended in solution, and will no longer contribute to scale deposition additives used during fracturing operations (such as gels or friction reducers).
The following depicts the results of a tube-block test (TBT) conducted by Weatherford Laboratories in Houston, TX. The TBT involves pumping water at a constant rate through a 1/16” diameter pipe, enclosed in a temperature and pressure controlled chamber; this process simulates down-hole well conditions. If the flowing pressure of the system increases over time as a sample from the field is pumped through the system, then scale is depositing in the pipe. This test is a popular means of assessing the efficacy and appropriate dosing for liquid scale inhibitors.
As seen below, and on dozens of tests just like this one from various fluids across the country, Ozonix® treated fluid does not deposit scale.
This particular sample is untreated and treated Marcellus shale flowback of approximately 30,000 mg/l TDS. Treated samples were immediately tested following treatment, then 60 days later, and even after 60 days, the water still showed inhibited scale potential. The fluid was treated at 70 barrels per minute.
Ozonix® treated fluid interacts notably better with other chemicals present in the completions fluid; particularly friction reducer. The most common type of friction reducer is a negatively charged (anionic) polyacrylamide. Because of its negative charge, this friction reducer is adversely impacted by multivalent cations like calcium, barium and iron. Ozonix® oxidizes or precipitates iron and divalent cations that would otherwise interfere with friction reducer.
In essence, the same drivers that cause the Ozonix® process to inhibit scale also cause anionic friction reducers to interact more favorably with Ozonix® treated fluid. Certain biocides interfere with the efficacy of friction reducing chemicals. Since there is no need to add biocide to fluid treated by Ozonix®, there is no biocide to interfere with friction reducer.
CoreLabs out of Dunca, OK conducted the following study with a friction loop. A friction loop allows for the testing of certain friction reducers (drag-reducing agents) with different waters. The study shows the efficacy of an anionic friction reducer with:
The data shows a significant improvement in the Friction Reducer efficiency, starting at a 7% improvement at 5 minutes, leading to a 27% improvement at 30 minutes. The treated water behaves much more like Duncan tap water than like flowback.