Solvent Content Measurements of the Produced Stable Water-in-Oil Emulsions During Solvent-Aided Thermal Recovery Processes

The in situ solvent-aided thermal recovery processes are promising methods for recovering unconventional oil resources due to their higher efficiency, lower energy and water consumption, and reduced environmental impacts. The produced stream is often a highly stable water-in-oil emulsion, where the oil phase comprises bitumen and solvent. Separating water from such a sample is challenging because conventional approaches result in solvent loss and sample contamination and render the solvent content measurement techniques currently employed by the industry invalid. Developing analytical techniques for solvent detection without sample dehydration, solvent loss, and contamination is essential for production surveillance, monitoring, process optimization, and economic evaluation. Solvent recovery and concentration measurement in produced streams have been considered the most important issues associated with the success and commercialization of solvent-assisted recovery processes. In this work, we implement a comprehensive chromatographic technique to measure the solvent concentration of the actual bitumen/solvent/water emulsions produced during a large 3D physical model experiment of the solvent-aided recovery process. We used combined gel permeation chromatography (GPC) and gas chromatography (GC) to obtain the full characterization of bitumen/solvent/water systems. After characterizing four produced emulsion samples, actual and synthetic multicomponent solvents are used to establish the necessary calibrations for rapid and accurate determination of the organic solvent content in the produced emulsion samples. The results demonstrated that the automated GC/GPC can be applied to actual minute amount emulsion samples for fast detection of solvent content in the pilot and field-scale projects of solvent-aided thermal recovery processes without sample dehydration while solvent loss and sample contamination are entirely avoided.