Product Sheet OS-1L Sulfite-Based Oxygen Scavenger
An ammonium bisulfite solution used to remove entrained oxygen from drilling and completion fluids.
OS-1L oxygen scavenger functions as a corrosion inhibitor by removing oxygen from the drilling or completion fluid while circulating. It is injected at the pump suction on a continuous basis to minimize atmospheric contact.
Traces of oxygen dissolved in the water can cause corrosion problems in the drillstring.
OS-1L oxygen scavenger is injected continuously at the pump suction by a specialized, metered pump that permits injection into the downhole fluid with minimal atmospheric contact. This is important because the ammonium bisulfite would be rapidly spent by atmospheric contact.
The sulfite ion is monitored at the flowline using an excess sulfite test to determine if sufficient scavenger remains available. When the fluid returns to the surface, it once again comes in contact with the atmosphere and begins to pick up oxygen causing the effective concentration of OS-1L scavenger to drop. Samples should be collected as close to the bell nipple as practical.
CONQOR 404 EH or WH corrosion inhibitor is often used with OS-1L oxygen scavenger in drilling fluids to assist in complete corrosion control. OS-1L scavenger is also used with CONQOR 303A or SAFE-COR corrosion inhibitors in completion fluids.
Initially, the oxygen scavenger is injected at a rate of between 1 and 2.5 galUS/h [3.8 and 9.5 L/h] at the pump suction. Sulfite determinations are made with fluid collected at the flowline, and the injection rate is adjusted upwards or downwards depending on the detected sulfite test results.
The desired excess sulfite content is 100–300 mg/L at the flowline. This level assures that there is sufficient sulfite in the drilling fluid to remove oxygen to the desired low level.
Often, corrosion rings are used to monitor corrosion rates over several days of drilling to evaluate the overall corrosion program.
Continuous injection of OS-1L oxygen scavenger is an important step in a comprehensive corrosion program. Significant factors affecting corrosion are as follows:
Bioassay information is available upon request. Handle as an industrial chemical, wearing protective equipment and observing the precautions described in the safety data sheet (SDS).
OS-1L oxygen scavenger is packaged in 5-galUS [18.9-L] cans and 55-galUS [208-L] drums.
Store in a dry, well-ventilated area. Keep container closed. Keep away from heat, sparks, and flames. Store away from incompatibles. Follow safe warehousing practices regarding palletizing, banding, shrink-wrapping, and stacking.