Hydrogen sulfide (H2S) gas is a colorless, transparent gas with a characteristic rotten-egg odor at low concentrations and no detectable odor at high concentrations – because by then the senses are deadened and it is deadly. H2S is found in petroleum and natural gas, and in addition to being one of the largest safety concerns, it also is a huge contributor to corrosion. Oil or natural gas is considered “sour” if it has a high percentage of hydrogen sulfide. To mitigate levels of H2S in oil and gas, scavenger chemicals are injected into the oil or gas stream.
One customer uses a specially formulated blend of amines designed for the effective and environmentally safe remediation of H2S. A Sentry® spring-loaded nozzle efficiently and cost-effectively disperses this H2S scavenger into a liquid stream.
A Bakken customer’s oil field of 14 wells was feeding gas with H2S levels of 10-12 ppm into the collection pipeline. Because H2S levels in the pipeline were required to be below 3 ppm, the customer had to shut in all 14 wells, costing them 5,800 barrels (bbl) of oil production, or approximately $260,000 per day (at $45 per bbl at the time).
The customer determined that treating the individual wells with multiple injection points, which would require the purchase of additional equipment including pumps and plumbing, could be avoided by treating at one injection point on the pipeline instead. Treatment of the pipeline began within 12 hours with a continuous application of the H2S scavenger chemical, administered using a Sentry spring-loaded nozzle. The initial treatment cost was about $117 per day.
Within 48 hours, H2S levels in the pipeline were lowered to 0 ppm, and the customer was able to re-open all 14 wells and restore production. The chemical treatment was then optimized, reducing the product and keeping the H2S at 0 ppm. The current dosage is treating all 15 mmcf (million cubic feet) of gas in the pipeline at a cost of about $50 per day, only a fraction of a cent per mcf (thousand cubic feet).
This infers a reduction in the chemical flow of nearly 60%, or a turn down ratio of 2.3:1. The same spring-loaded nozzle was used, providing efficient dispersion over the entire chemical flow range, without needing to make any expensive changes to the chemical injection system.
After four months of treatment, H2S levels in the pipeline have remained at 0 ppm and no wells have needed to be shut in. Equipment purchased for the pipeline treatment cost approximately $6,000, more than paying for itself immediately.
The Sentry spring-loaded nozzle can be attached to Sentry chemical injection tools, which are part of our highly integrated corrosion monitoring and chemical injection product portfolio. These durable products for high- or low-pressure applications offer ease of use and custom configuration for versatility. They have been thoroughly tested to perform consistently and repeatedly in rigorous environments to minimize corrosion and safety risks.
Learn more about our chemical injection solutions for oil and gas extraction, petrochemical, refining and pipeline environments.