(66c) Effect of Oil Filtration on Oil-Water Dispersion Characterization

Oil-water emulsions make up a significant percentage of the world’s crude oil production. Emulsions generate operational problems in the Petroleum Industry, such as incremental pressure drop, decline in oil production rate, and equipment corrosion, among others. Crude oil naturally includes solid nano-particles and other surface-active agents, such as asphaltenes, resins, inorganic salts, bases, and acid end groups. The agents can act as stabilizers for oil-water emulsions when present in the interface and promote interfacial viscosity, which hinders the droplet-droplet coalescence. The objective of this paper is to investigate the effect of the removal of surface active agents on the stability of the oil-water emulsion under different water cuts and crude oil filtration media pore size.

A state-of-the art Portable Dispersion Characterization Rig (P-DCR) is utilized to study the effect of crude oil filtration on oil-water dispersion characterization. The P-DCR is a batch separator that includes a separation cell where the oil and water are introduced, sheared, and allowed to separate over time. The device is equipped with a high-resolution camera, and data acquisition software that tracks and analyzes the separation profiles. Oklahoma crude oil and distilled water are used as fluid phases, which are sheared with rotational speed of 600 rpm for a total time of 10 min. The experiments are collected with four water cuts, namely, 15%, 25%, 50%, and 75%. A filtration flask attached to a vacuum pump was used for the filtration process. Filter papers with pore sizes of 8 and 20-25 µm were used as filtration media for the removal of the surface active particles from the crude oil.

The experimental data show that the fastest separation occurs with increasing water-cuts for both filtered and unfiltered crude oil. The filtration of crude oil results in a faster separation as compared to unfiltered cases for low water cuts, namely, 15% and 25%. However, the effect of crude oil filtration on the separation rate is negligible for higher water cuts due to the lower concentration of the surface-active agents in the emulsion. The experiments confirm that the smaller pore size filtration media results in an increased removal of surface active particles, resulting in ahigher separation rate for lower water cuts.