Characterization of emulsions and suspensions in the petroleum industry using cryo-SEM and CLSM

Confocal laser scanning and cryogenic scanning electron microscopy techniques for imaging colloidal systems are discussed. The advantages of each technique are shown along with examples of emulsions and suspensions from the petroleum industry. Given the sample preparation and manipulation that is sometimes required for cryo-SEM observation, the degree to which the images actually represent the sample morphology can be in doubt. An example from the study of oil sands tailings suspensions shows that sample preparation artifacts can be subtle and deceptive. Ultimately, direct observation should be used in conjunction with, or as support for conventional characterization techniques of colloidal systems, not as a substitute.