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Offshore Waterflood (Dissolved Oxygen)

Offshore Waterflood

 A typical waterflood process contains several unit operation stages along with chemical treatment additions to achieve the required water quality. In its most basic form it consist of filtration to remove solids, deaeration (DA) or oxygen stripping to reduce the oxygen, sulfate removal unit, along with chemical additions to purify against organism growth (barnacles, mussels, microorganisms and bacteria) and compliment the above unit operations.

Issues with Traditional Dissolved Oxygen Sensors

Typically, electrochemical dissolved oxygen cells have been utilized throughout the industry and have proven very problematic for the waterflood applications. Poor reliability, accuracy and high-maintenance of the electrochem cells left technicians and operators with little faith in the measurement over time. All electrochem cells have anodes, cathodes, electrolyte solution and a sensitive membrane in contact with the process. The seawater salinity and process chemicals attack the cell’s electrolyte and electrodes causing offsets and requiring frequent calibrations. The fouling present in the process coats the cell membrane also causing errors and high maintenance.

Using Precision Optical Oxygen Analyzer in Waterflood
Barben Analytical’s precision oxygen analyzer, OXYvisor, uses a proven optical luminescence technique enabling high accuracy at ppb levels along with high dependability and low maintenance. The analyzer is hazardous area rated and compliant for offshore installation requirements. The sensor is unaffected by flow or pressure in liquid streams and can be placed in a simple sample stream. Coatings on the sensor tip may affect the measurement speed by slowing oxygen diffusion however do not affect accuracy. The optical technology does not contain electrolyte and does not react with the process and therefore the stability is excellent. Under normal “tough,” operation users have set calibration periods for 30 or more days depending on expected accuracy.