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CANADIAN HEAVY OIL ASSOCIATION

SPE/PS-CIM/CHOA 97786 PS2005-XXX Advanced Electrostatic Technologies for Dehydration of Heavy Oils
William H. Thomason/SPE, David J. Blumer/SPE, Probjot Singh/SPE, and David P. Cope, ConocoPhillips, and Moshen Zaouk, NATCO
Copyright 2005, SPE/PS-CIM/CHOA International Thermal Operations and Heavy Oil Symposium This paper was prepared for presentation at the2005 SPE International Thermal Operations and Heavy Oil Symposium held in Calgary, Alberta, Canada, 1–3 November 2005. This paper was selected for presentation by an SPE/PS-CIM/CHOA Program Committee following review of information contained in a proposal submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the Society of Petroleum Engineers, PetroleumSociety–Canadian Institute of Mining, Metallurgy & Petroleum, or the Canadian Heavy Oil Association and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the SPE/PS-CIM/CHOA, its officers, or members. Papers presented at SPE and PS-CIM/CHOA meetings are subject to publication review by Editorial Committees of the SPE and PS-CIM/CHOA.Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of the SPE or PS-CIM/CHOA is prohibited. Permission to reproduce in print is restricted to a proposal of not more than 300 words; illustrations may not be copied. The proposal must contain conspicuous acknowledgment of where and by whom the paper was presented. Write Librarian,SPE, P.O. Box 833836, Richardson, TX 75083-3836, U.S.A., fax 01-972-952-9435.

Abstract Effective oil/water separation continues to be a major challenge in heavy oil (HO) production operations and often involves high capital costs (large, heated vessels) and high operation costs (heat, fouling, upsets, chemicals). Application of new electrostatic dehydration technologies has the potential to havea major impact in reducing these costs. A systematic evaluation of four electrostatic dehydration technologies was performed using lab, bench scale, and pilot scale (40 gallons) testing. Four heavy oils ranging from 8 to 21 API were used. Performance criteria measured were effective emulsion separation rate (vessel throughput), separated oil and brine quality, water droplet size distribution forinlet and outlet emulsions, and comparison with field data (as available) for older electrostatic technologies. Traditional bottle tests were performed for reference. A 2 to 4 fold increase in emulsion treating rate was observed for some of the heavy oils using the newer electrostatic technologies relative to the traditional Alternating Current (AC) method with the same output quality of crude andbrine. Relative cost data per barrel of emulsion processed were developed from system cost estimates and throughput data developed in the pilot tests. Treatment with acid to bring the separated brine into a 6 to 6.5 pH range had a very beneficial effect on the oil/water separation for some of the heavy oils with high TAN. Introduction Effective water removal from heavy oils (HO) often involveshigh capital costs (large, heated vessels) and high operation costs (heat, fouling, upsets, chemicals) that impacts both upstream and downstream (desalting) operations. New electrostatic dehydrator technologies offer the potential to

have a major impact in reducing these costs1, 2. An evaluation of some of these new technologies using four different heavy oils was performed to compare the relativeperformance and costs of four electrostatic dehydrator technologies in dehydration of these four heavy oils. Why is water separation (dehydration) an increased challenge for Heavy Oils? The two major reasons for the more challenging dehydration of HO are their high viscosity and the small density difference between the HO and the brine. The high viscosity slows the mechanical separation...