Certain production regions globally are now facing similar challenges with process mercury as E&P companies drill deeper into higher temperature-pressure formations increasing the potential of encountering elevated levels of mercury in production. Mercury, a naturally occurring trace contaminate in hydrocarbons like natural gas, condensate and crude oil presents unique worker safety and processing challenges to the upstream sector.  The concentration of mercury in natural gas and associated liquids varies with geology and reservoir conditions.

Process mercury from offshore production assets or onshore gathering systems eventually equilibrates with carbon and stainless steel tubing, piping and vessels such that mercury concentrations in inlet streams to process plants will increase to close to the concentrations at the well head. It makes the most sense to remove mercury as far upstream as possible and this is an increasing trend. Mercury removal is now applied successfully to gas streams upstream of dehydration and acid gas removal with commercially available medias that are somewhat resistant to entrained water and hydrocarbon.

In addition to spent MRU medias a variety of hazardous waste streams are generated in the upstream sector some of which may be managed under E&P exemptions and injected into disposal wells or rocked back into the formation in certain cases. Mercury is inconsistently regulated by governments, but discharges of mercury are overall severely restricted due to mercury’s toxic and persistent nature. Also there is limited regulatory guidance for how much mercury may remain in steel process systems like subsea pipelines, FPSOs and topside processing systems. There is however some industry guidance for impacted steel as related to decommissioning of assets that are to be recycled. In all cases caution is warranted when dealing with mercury contaminated waste streams to mitigate risks to workers and release to the environment.