Emulsified water droplets must be extracted from crude oil for economical and transport purposes, which is achievable by chemical demulsification. Four different chemicals were tested on water-incrude oil emulsions using a newly developed NMR method. Droplet size distributions were mapped at the beginning and end of experimentation. In addition, slice selections (soft RF pulses) were used to isolate the signal from residual droplets within the separated oil phase to study coalescence patterns in the emulsion bulk. The NMR could also return rapid continuous brine profiles for analysis of sedimentation rates and free water appearance kinetics. The residual water content was isolated by strong bi-polar gradient suppression, thereby allowing focus on the smaller droplets still emulsified in the top region in the brine profiles. Optimum concentrations were found for each chemical, and blends of several chemical demulsifiers were noticeably more efficient than the single component demulsifiers in this study.

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In this work we studied electrocoalescence behavior of stable pendent drop pairs and compared the results to the clean drops, where the interface is void of surface-active compounds. The drop phase is brine and the drop-oil interface is stabilized by aging into asphaltene and demulsier solutions. The experiments involving asphalteneladen drops required the bulk phase to be clear for visualization of the drops, which is realized by a procedure to replace the asphaltene-containing dark bulk phase by a pure solvent mixture. The narrowly spaced pendent drops, maintained at dierent electric potentials, acquire net surface charge of opposite polarity which leads to the Coulombic attraction in the drop-pair. After the application of voltage, a drop pair observed to be remained at a standstill, attracted or coalesced depending on the inter-drop separation, drop size, and potential dierence. We systematically investi-