Flooding experiments in sandpacks were performed to investigate the potential use of diluted oil-water macro-emulsions as an EOR agent for viscous oils. The emulsion dispersed phase was the oil in place in the sandpack. Oil recovery factors obtained with emulsion flooding were compared to synthetic sea water injection and surfactant solution injection. Results have indicated a reduction in cumulative water-oil ratio and an increase in oil production after a bank of emulsion was injected. At the appropriate conditions, emulsion oil drops block pores already swept by water flooding, changing the residual oil saturation and mobility of the water phase, and therefore mobilizing oil. The increased volume of oil produced was a function of the drop size of the emulsion. Produced water can be considered as a diluted oil-in-water emulsion. The results presented here suggest the possibility of using an effluent as a resource, after appropriate treatment, in IOR projects.

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Displacing fluids in downhole conditions and for long distances is a complex task, affecting several steps on well construction. Cementing gains relevance in the moment that fluid contamination compromises cement sheath integrity and consequently zonal isolation. Density and rheology design for all the fluids involved are essential to achieve operational success. Properties hierarchy and preferred flow regimes have been empirically defined and tend to provide reasonable generic results. Challenging operations, including ultra deepwaters and their narrow operational windows scenarios, require further knowledge of the physics involved in order to prevent undesirable events This article presents the in house development of a software for annular two-phase flow, which analyzes fluid displacement in typical vertical and directional offshore wells, for Newtonian and non Newtonian liquids, laminar and turbulent flow regimes. The formulation proposed provides accurate results for a wide range of input parameters, including the cases in which the ratio between the inner and outer radii of the annulus is small. Operational guidelines for fluid and placement schedules are provided. The computational work is validated by unique results obtained from an experimental test rig where detailed displacement tests were conducted. Contamination degrees were measured after the displacement of a sequence of fluids through 1192 m of vertical well. Effect of fluid density and rheology hierarchy, flow regimes and displacement concepts were investigated. The results provide relevant information for the industry and fundamental understanding on displacement of Newtonian and non Newtonian liquids through annular sections.