Pore-scale analysis of filtration loss control by Colloidal Gas Aphron Nano-Fluids (CGANF) in heterogeneous porous media

• Blockage ability of a new colloidal gas fluid, CGANF, is investigated.
• Pore-scale behavior of CGANF in heterogeneous and fractured porous media.
• CGANF improved filtration loss control by forming an effective seal.
• Use of Olea Europaea and fumed silica nanoparticles in CGANF.
• Analysis of return permeability for flow of CGANF in fractured micromodel.

This study concerns micro-scale analysis of filtration loss control induced by blockage ability of a new colloidal gas fluid, Colloidal Gas Aphron Nano-Fluid (CGANF) in fractured porous media. Fumed silica nanoparticles and a novel environmentally friendly bio surfactant, Olea Europaea, were used for monitoring CGANF displacements in heterogeneous micromodels including single fracture. Analysis of pressure drop along the micromodel during tests showed an increasing resistance to flow of CGANF dispersion through porous media as more CGANF was injected. When lamella division occurs, more small bubbles are formed and then pressure drop through porous media increases. Small bubbles play an important role in blocking the porous media due to the fact that they change the direction of larger bubbles in fracture and also due to their lower mobility compared to larger bubbles. Observations revealed that CGANF microbubble built up across the pore structure could establish an effective seal for controlling filtration loss. The permeability of the porous media can be returned to the original state. For the cases studied here, the highest value of return permeability for fractured and un-fractured heterogeneous patterns were 71.11% and 78%, respectively. Nanoparticles improved the blockage ability of CGANF injection at 0.1 w/v% concentration as an optimum concentration. This study provides new insights into the pore blocking ability and formation damage control induced by CGANF in heterogeneous systems.