Effect of Thermodynamic Parameters on the Concentration of Pollutants in Produced Water from Crude Oil Production

Abstract

Thermodynamic parameters such as temperature and pressure of petroleum reservoirs are among the most important physical characteristics which are required to effectively produce crude oil from the reservoirs. Oil and gas reservoir pressures determines if external energy is required to force well fluids out of the reservoir; the temperature of the reservoir determines the flow characteristics of the produced fluid through the tubing and along the flowline by its influence on the viscosity of the fluid. The produced fluid is made up of produced water, crude oil and natural gas. Produced water contains several substances which at certain concentrations could pose health threats to living organism in the environment. Local regulatory authorities do not allow discharge of produced water to the environment except the prescribed limits for selected pollutants contained in the produced water are not exceeded. This has led to post-production treatment of produced water in most crude oil production facility in order to meet these limits. This treatment increases the cost of production of crude oil thereby reducing the profitability of crude oil production process. It is believed that thermodynamic parameters such as temperature and pressure are capable of either decomposing or altering the structure of some pollutants thereby reducing their concentration in the produced water at the end of the production process. This research has employed an environmental process engineering simulator (Aspen HYSYS) to determine which thermodynamic variables of temperature and pressure could be altered in combination to reduce the concentration of pollutants in produced water to meet the regulatory limits prior to discharge.