Olalekan S. Alade

Kinetic analysis and modeling of stability of bitumen-in-water emulsion stabilized by polyvinyl alcohol (PVA)

ABSTRACT Description of emulsion stability is an essential aspect of process design and development for separation and production operations. In this investigation, bitumen-in-water emulsions were formed with bitumen contents (CB) of 50% and 70% w/w stabilized in the aqueous solution containing Polyvinyl alcohol and dissolved salt ranging from 0.5% to 3.5% w/w. Water separation under gravity was monitored in real time at isothermal condition. Data collected were used in evaluating kinetic parameters and developing model to predict the stability of emulsions with time. The model was found to adequately predict the emulsion stability under the conditions of the investigation.

An aspect of bitumen emulsification by steam condensation: Effect of formation temperature and bitumen content

ABSTRACT The experiments to form emulsions of bitumen including fine droplets of condensate water were carried out for an average formation temperature range; Tf = 38–69°C and bitumen content; CB = 29–82%. It was observed that the water retention capacity or stability of the emulsions after mild agitation was significantly affected by formation temperature and content of the bitumen. The particle size of water droplets in emulsion decreased with increasing formation temperature. However, bitumen emulsions showed similar shear thinning non-Newtonian behavior in spite of the formation temperature, since water droplets in the emulsions changed under shear flow to smaller size similar to ones formed at the higher formation temperature.

Measurement of viscosity alteration for emulsion and numerical simulation on bitumen production by SAGD considering in-situ emulsification

A thermal steam stimulation process, such as steam-assisted gravity drainage (SAGD), induces water-in-oil emulsion of heavy oil or bitumen throughout the production. The present study investigated the effects of in-situ emulsification in the oil sands reservoir for SAGD process. The viscosities of water-in-oil emulsions produced were measured with respect to water-oil ratio (W/O), shear rates, pressures and temperatures. The results therefore were employed to develop the numerical model of viscosity alteration. Numerical simulations of the SAGD bitumen production considering viscosity alteration were also carried out to investigate distribution characteristics of emulsion, water, and bitumen at steam chamber boundary and effects of in-situ emulsification on bitumen production behavior. With a model named SAGD-Emulsion Model, it was found that the net recovery factor of bitumen for this model is 5 to 10% higher than that of conventional SAGD simulation. Ultimately, it was found that the recovery factor of bitumen increased with W/O of emulsion generated in the reservoir since higher water content would invariably allow bitumen to flow at higher relative permeability, while the increase in viscosity merely delayed bitumen production.