Polymer flood using partially hydrolyzed polyacrylamide (HPAM) has proven to be an effective method for increasing oil recovery. However, when HPAM breaks through the reservoir and shows up in produced fluids, it brings unique emulsion characteristics and challenges to the separation processes.
Operators have experienced frequent equipment failures on heat exchangers and heating elements. Traditional oil dehydration uses mechanical heater treaters, which rely on elevated temperature to improve the settling of the dispersed water phase. In HPAM flood, the fire tubes in these mechanical heater treaters have become problematic and experienced repetitive failures.
Electrostatic technology uses the response to the electrostatic field by the polar dispersed water phase to enhance water settling. Electrostatic technology has been a proven technology for oil dehydration and desalting for waterflood and other recovery methods such as steam-assisted gravity drainage (SAGD), but it is not widely used in HPAM flood.
A joint study was conducted by Cameron and Cenovus to evaluate the electrostatic dehydration of heavy oil from HPAM flood. The results of the study indicate that because of the presence of HPAM in water, the electrostatic dehydration of the wet oil demonstrates some unique characteristics. Electrostatic dehydrators can achieve about 300% the capacity of mechanical heater treaters. Proper equipment and process designs are important to reduce equipment failures. The results of the study offer a more effective oil dehydration technology to the HPAM flood producers. The benefits of electrostatic dehydration can be especially valuable for offshore implementation of HPAM flood because of the space and weight savings.