Effect of Emulsion Breakers on Interfacial Tension Behavior of Heavy Oil-Water Systems

摘要

Bottle testing for emulsion breakers (EBs) in steam-assisted gravity drainage (SAGD) operations is a standard practice; however, it has been observed that, in some cases, EBs recommended via bottle tests can fail during field trials as a result of conditions being disparate, such as higher temperatures and pressures in the field that cannot be safely or easily replicated in the lab. To make better EB recommendations, an optimized methodology based on interfacial rheology measurements was developed. Compressibility tests performed at different temperatures (80-120 degrees C) were used to compare effect of EBs on parameters such as initial compressibility, initial interfacial tension, phase transition ratio, and drop crumpling or detachment ratio (ratio of the compressed surface area to the original surface area at which the interface starts to collapse or at which the drop detaches). Furthermore, the addition of the EB to the oil phase versus aqueous phase was investigated. The effects of EBs at the oil/brine interface can be quantified using compressibility tests at temperatures and pressures similar to those encountered in the field. This approach shows a good correlation with field results and demonstrates that these techniques can be used to supplement the standard bottle test for more effective screening of EBs.