FAQs associated with produced mercury in oil and gas addressing issues and concerns for E&P, midstream, downstream and petrochemical sectors. This is series 1 of a multi-part series planned for publication. We are happy to address questions from contacts, followers and our readers.

1. Q
A
What is Produced Mercury and What’s the Big Deal?
Mercury is a naturally occurring trace constituent in hydrocarbons including crude oil, condensate and natural gas.
Virtually all geologic hydrocarbons contain measurable quantities of mercury. The concentration of mercury in
natural gas and associated liquids varies with geology and reservoir conditions with the highest observed concentra-
tions occurring in Southeast Asia, Asia-Pacific, Australasia, European Union and Russia. Other geographic areas
include North Africa, the Americas and China. Of note, the highest concentrations in natural gas (>2000 micrograms
per standard cubic meter-gas - mg/scm) have been found in Southeast Asia, Australasia and recently in deep shelf
gas in the Gulf of Mexico. Coal Bed Methane (CBM) production can contain higher mercury concentrations than
traditional or shale gas production, which applies to certain liquefied natural gas (LNG) offshore based assets. The
discovery of mercury in natural gas and condensates associated with shale gas plays throughout the U.S. and Canada
is a relatively new occurrence and has raised the awareness that trace concentrations present complicated health
risks, environmental risks, and hydrocarbon processing risks to pipeline transport/gathering systems, natural gas
liquids (NGL) and LNG plants.
Q
A
How Does Mercury from the Formation Contaminate Process Equipment?
High bottom hole temperatures and pressures > 200 C cause HgS and HgSe to decompose to elemental Hg which
then via adsorption and chemisorption is scavenged by tubing, flowlines, production equipment thus ending up in
products. Accumulation rates in metal process systems (i.e., pipelines and production equipment) can range from
1 gram/m2 to 100 grams/m2 which increase occupational exposure and environmental risks over an assets life-cycle
but more importantly underscores the need to have a decontamination plan prior to COP and decommissioning such
that mercury condensed and complexed into subsea pipelines does not become bio-available and impact marine
ecosystems.
A
Q Is there a Safety, Environmental and Process Impact from Produced
Mercury in Unconventional Resources to Midstream and LNG Plants
and Can it be Quantified?
Yes, as the US and Australia have developed unconventional resource plays many new NGL plants have been built
throughout North America in Shale Gas Plays that have measured mercury concentrations exceeding the low tolerance
of NGL/LNG plants (10-100 ng/scm). Also, as Australia has increased production from unconventional resources in
Eastern Australia from CBM to ~30% of total production (primarily from the Bowen and Surat basins in Queensland)
and shale gas drilling has increased in the NT and WA (Kyalla and Velkerri shales) risk to the environment from water
management and certain regen processing streams that vent to ATM directly or through a thermal oxidizer have
increased (glycol regen and amine regen streams). NGL and LNG plants have a low tolerance for mercury in process
(10-100 nanograms/scm) to protect the cryogenic process trains and require a measurements program throughout
the life-cycle of the asset to quantify risks. As for occupational exposure, mercury should be monitored in process
and during maintenance and inspection from the plant upstream to the Central Processing Facility (CPF) to the
Central Gather Facility (CGF) to mitigated over exposures to workers during routine maintenance and inspection
[pipeline pigging, hot-work and tank gauging (mercury accumulation in metals, process, condensates, tanks etc.)
Copyright © 2019 ISCT GROUP US LLC (ISCT™). All Rights Reserved. 1
FAQ:1
MERCURY IN OIL AND GAS: Frequently Asked Questions and Answers
for the Upstream, Midstream, Downstream and Petrochemical Sectors
ISCT™
SpecTech
SERIES 1 | JUNE 11, 2019

2. Q
A
Are Floating Assets Such as Floating Production Storage and
Offloading (FPSO) Vessels Effected as Well?
Of course, many floating assets (i.e., FSO, FPSO, FGSO and FLNG) are geographically located in regions with variable
concentrations of metals in process (e.g. mercury and arsenic) which require measurements in process to quantify risks
to the asset, personnel and the environment over the life-cycle of the ship. Some FPSOs are now designed with sample
locations for measurements of mercury in process and engineering controls to minimize accumulation of mercury
throughout the asset. Depending on use such as oil production, gas processing or gas export mercury metals loading
per surface area, species of mercury and depth of penetration into chemically coated metal hull sections or carbon-
stainless steel process systems vary (1-100 grams/m2, elemental Hg to HgS and penetration into scale, coating or
substrate depends on many factors) but require considerable understanding prior to decommissioning. This is a
global concern as there are about 185 floating assets around the world (many are in service in the global mercury belt
and others are planned for service for new deep production) which means many of these assets are contaminated
with mercury, other hazardous metals and NORM and require assessment, ongoing monitoring and a comprehensive
management plan for safe operation and future planned decommissioning. Many of these assets are owned and
operated by a select group of global oil and gas companies that will operated and decommission responsibly given
the option while others are owned by JVs and operators that may not have a corporate environmental policy that
transcends the local environmental regulations where the asset operates. Even using conservative mercury in
steel mass loading rates this equates to massive amounts of mercury entrained in these assets entering the mercury
cycle during operation and post decommissioning (depending on many factors including deinventory practices,
decommissioning procedures and what country the asset is decommissioned in).
A
Copyright © 2019 ISCT GROUP US LLC (ISCT™). All Rights Reserved. 2
™
ISCT
Ron Radford
Principal Partner
m: +1 (713) 503-6803
m: +66 098 495 5474
e: r3@isctgroup.com
w: isctgroup.com
Derek Peterson
Chemical Engineer
m: +1 (337) 302-7666
e: dpeterson@spectechservices.com
w: spectechservices.com
Q
A
How Does Produced Mercury Effect Operations in the E&P Sector?
Certain production regions globally are now facing similar challenges with produced mercury as E&P companies drill
deeper into higher temperature-pressure formations increasing the potential of encountering elevated levels of
mercury in production. The precise and accurate measurements of mercury in process is critical to understanding
risks over the life cycle of the asset. Mercury accumulation in metals (carbon and stainless steel) and process
systems impact personnel and the environment and require quantification and speciation to protect personnel and
mitigate emissions to the atmosphere. Further, as produced mercury is corrosive to cryogenic process trains through
LME and AMC (LNG and NGL) inaccurate measurements have a negative impact to process and can result in
catastrophic failure.
FAQ:1
MERCURY IN OIL AND GAS: Frequently Asked Questions and Answers
for the Upstream, Midstream, Downstream and Petrochemical Sectors
ISCT™
SpecTech
SpecTech
SERIES 1 | JUNE 11, 2019