English abstract
Mercury is a naturally occurring heavy metal, which is produced along with natural
gas and other petroleum liquids. Mercury is liquid in room temperature with a
considerably high vapor pressure. The association of mercury in petroleum reservoirs
is difficult to explain and secondary geological processes are assumed to be the main
mechanism for transporting mercury to the petroleum reservoirs. During the
production of natural gas and petroleum liquids the distribution of mercury in different
process equipment and streams should be correctly known to assess the potential of
mercury release to environment and occupational health issues related to it. Mercury
is considered as a toxic compound and once released to the environment the fate of
mercury is usually a bio-accumulation in the biological systems. Performing regular
lab analysis and experimental mercury mapping study is not an easy task to perform.
In the field operators should wear special equipment to reduce the risk of mercury
exposure, and the sampling system should be sophisticated and done by professionals
to correctly take a measurable sample. The operating companies usually don't have
such experience in sampling and handling mercury in petroleum fluids. This report
studied the performance of different commercial software against field and
experimental data to establish a basis for performing filed analysis less regularly. The
report also discussed in detail the distribution behavior of mercury in different types
of natural gases, different concentration of acid gases, optimum location of mercury
removal units, different gas processing plant capacities and different operating
pressures. The study emphasized that the type of gas produced is the main determinant
factor to decide on the mercury management program to be used in the gas processing
plant. As the gas become richer in heavier liquids the distribution of mercury into the
liquid phase will increase. Finally, a retrofit design is proposed to eliminate the
environmental releases and increase the recovery of the gas processing plant. By
retrofitting the original design, it has been found that the environment released
decreases to negligible amounts, more mercury can be separated safely in the mercury
removal units and extra mercury will also dropped to the liquid phase. Additional
benefits of the retrofitting process are also observed in terms of increase in the export
gas and liquid recovery amounts and significant reduction in flaring and incinerating
gases.
