Treating Emulsions Produced By Thermal Recovery Operations
Authors: Bansbach Paul L. 
Published: December 2007

Publication Rights Reserved

This paper to be presented at the 36th Annual California Regional Fall Meeting of the Society of Petroleum Engineers of the AIME in Bakersfield, California on November 4–5, 1965 and is considered the property of the Society of Petroleum Engineers. Permission to publish is hereby restricted to an abstract of not more than three hundred words with no illustrations unless the paper is specifically released to the press by the editors of the Journal of Petroleum Technology for the Executive Secretary. Such abstract shall contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the Journal of Petroleum Technology or the Society of Petroleum Engineers Journal is granted on request providing proper credit is given that publication and the original presentation of the paper.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers Office. Such discussion may be presented at the above meeting and with the paper may be considered for publication in one of the two Society of Petroleum Engineers magazines.

Knowledge of the nature of emulsions and demulsification is important in resolving any emulsion. The theory of emulsions and demulsification is reviewed. The method of treating emulsions, chemicals, heat, electricity and time are discussed; how they influence the emulsion and how they are applied in actual operation. The treating of emulsions produced by thermal recovery operations follows the same pattern as used for other emulsions. However, it is necessary to increase the magnitude of some or all of the applied factors.

Introduction

The expansion of the use of thermal stimulation methods has brought with it an increase in the severity of produced emulsions. In-situ combustion produces unusually large quantities of emulsion stabilizing elements. Materials removed from the formation by steam tend to stabilize emulsions. Difficulty is encountered in removing steam condensate from crude. These and other factors contribute to the difficulty encountered in treating thermally stimulated production.

These emulsions are not different in character from others but they are different in degree. Therefore, a better understanding of emulsification and demulsification will provide a basis for establishing a treating program to handle such emulsions.

All crude oils, regardless of their origin, contain certain characteristics which tend to make them emulsifiable. Therefore certain principles must be adhered to when treating any emulsion. Our first step then will be a review and discussion of the theory of emulsification and demulsification.

An emulsion by definition is a stable dispersion of one liquid in another. Not every mixture or dispersion of water in oil is an emulsion. The dispersion must be a stable one. A dispersion characterized by very small water drops is said to be a tight emulsion (Figure 1); one characterized by large water drops is a loose emulsion (Figure 2). In the oil field, where water and oil are the two liquids, two types of emulsions are formed. They are the oil-in-water and water-in-oil emulsions. Since the water-in-oil type is more common, this discussion will center around it with a brief review of the oil-in-water emulsion later.