Electrostatic Dehydration of Heavy Oil from Polymer Flood with Partially Hydrolyzed Polyacrylamide

Abstract

Polymer flood using partially hydrolyzed polyacrylamide (HPAM) has been proven to be an effective method to increase oil recovery. However, when HPAM breaks through the reservoir and shows up in the 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 the water settling. Electrostatic technology has been a proven technology for oil dehydration and desalting for water flood and other recovery methods such as Steam Assisted Gravity Drainage (SAGD), but not widely used in HPAM flood. A joint study was conducted between Cameron and Cenovus to evaluate the electrostatic dehydration of the heavy oil from HPAM flood. The results of the study indicate that, due to the presence of HPAM in water, the electrostatic dehydration of the wet oil from HPAM flood demonstrates some unique characteristics. Electrostatic dehydrators can achieve about 300% of the capacity of mechanical heater treaters. Proper equipment and process designs are important to reduce the 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 the offshore implementation of HPAM flood due to the space and weight savings.

The effect of NaCl and HPAM solution concentration on HPAM gel structure degradation by ultrasonic waves

“…The presence of free gel structures can lead to complications in field separation and oil transportation from the producer to the pipeline. [23][24][25] These particles can plug pump strainer nipples, causing issues in water filtration units and disrupting the treatment process by not allowing proper heating in the treater, as they often form a barrier at the oil-water interface. [20,26] Also, the presence of gel structures can accelerate the plugging of conventional bag filters.…”

“…Zheng et al [ 25 ] evaluated the application of electrostatic dehydration on heavy oil from HPAM flooding. Electrostatic dehydration is a more advanced technology compared to mechanical dehydration, which uses a fire tube heater.…”