Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Experimental investigation of emulsion flow at pore scale in fractured porous media
Submission Author:
Marcio CARVALHO , RJ , Brazil
Co-Authors:
Alandmara Rosa Dionizio Leôncio, Ranena V. Ponce F., Marcio CARVALHO
Presenter: Alandmara Rosa Dionizio Leôncio
doi://10.26678/ABCM.COBEM2023.COB2023-1712
Abstract
Naturally fractured reservoirs (NFR) provide over 20% of the world’s oil reserves. It presents high complexity due to the presence of regions with distinct characteristics in terms of permeability and porosity. High permeability fractures provide preferential water paths leading to a rapid decline in oil production. Emulsion flooding is an effective Enhanced Oil Recovery (EOR) technique, successfully used to block water preferential paths by reducing water mobility. Displacement experiments have shown that more than 15% of the remaining oil in reservoirs can be recovered by emulsion flooding compared to water flooding. As the emulsion droplets flow through the porous medium, they act as a mobility control agent blocking pore passages already swept by water, reducing viscous fingering and the residual oil saturation, consequently improving oil recovery. In this work we studied emulsion flow in NFR at pore scale through a microfluidic device designed with a central fracture flanked by high and low permeability zones, and at Darcy scale through a longitudinally cut Bentheimer sandstone core, to mimic a NFR. In the rock, the fracture was simulated using a polyoxymethylene spacer filling the voids with spheres with controlled size, providing a porous medium with very permeability contrast. The stability of O/W emulsions was studied by droplet size distribution (DSD) variation with time and by bottle tests. The flow of emulsions was evaluated through injectivity and oil displacement experiments. The injection tests were performed at high and low capillary numbers, as capillary forces are an important parameter governing oil trapping, and were evaluated through the mobility reduction factor (f) and the residual resistance factor (RRF). Results showed the water mobility control exerted by the emulsion droplets through permeability reduction of the fractured models as a function of the emulsion DSD and capillary number. Emulsion injection with DSD in the same order of the average pore diameter of the fracture region showed moderate damage and significant pressure oscillation indicating that the emulsion droplets were blocking the pores and deforming until they can proceed towards the throats, evidencing the emulsion mobility control effect.
Keywords
Naturally Fractured Reservoirs, Emulsions, EOR
