Off-Shore Mercury Measurements

ISCT Group US LLCServicesOff-Shore Mercury Measurements

»Off-Shore Mercury Measurements

There are several methods for performing offshore mercury assessments: process stream sampling and analysis (onsite or offsite analysis), non-destructive-direct measurements (XRF), subsampling (sludges/sediments/equipment scale), or destructive testing (sacrificial flanges, pipe spools, corrosion or test coupons).

Process stream sampling (natural gas, condensate and produced-water) is the primary and essential method for determining contaminate mass and flux of mercury, arsenic and selenium on a continuing basis during the operation of the asset. Process stream sampling, along with system mapping, speciation and partitioning can often provide a near-complete picture of the contaminant loading and allow for targeted assessment of systems (metals equilibration rates, mass loading and distribution are not equal in all sections of processing). Short-term and long-term process stream samples are collected from process under operating conditions and pressures using mercury inert insertion probes and specialized mercury inert sampling and measurement equipment capable of performing sampling/analysis per requirements of ASTM D6350, ISO 6978 and MEPA 30B (co-developed by ISCT members).

ISCT members have advanced mercury and volatile metals measurements in wet gas streams over the last since 2005 and can deploy explosion proof M4 mercury monitoring units from the US Gulf Coast, Australia, New Zealand and South Africa.

The sampling of mercury is complicated due to the chemical properties of mercury – analysis has been well understood for the last decade. If measurements are not performed with total precision and accuracy, then the data will be unreliable and result in impacts to process plants onshore. This is the case in more than one geographic region where now assets are having to manage considerably more mercury in process than was planned.

Off-shore production assets (i.e., riser platforms, production platforms, gathering platforms and FGSO’s, FPSO’s and FSOs) can become contaminated with mercury, arsenic and other contaminates and require routine testing. The precise and accurate measurements of mercury in upstream wet gas environments is critical to understanding risk to process, distribution and total asset management. ISCT’s M4 mercury measurements systems and mobile CVAFS easily deploy on planes and in most helicopters with sample and analytical specialists.