Sharif Digital Repository

Wettability alteration is the principal low-salinity-effect (LSE) in many oil-brine-rock (OBR) systems. Our recent experimental results have demonstrated that wettability alteration by low salinity is slow. It is expected that the electrical behavior of oil/brine and rock/brine interfaces and the water film geometry control both the transient hydrodynamic pressure, and the time-scale of ionic transport in the film, thus the kinetics and degree of wettability alteration. In this paper, the electro-diffusion process induced by the imposed ionic strength gradient is simulated by solving Poisson-Nernst-Planck equations in a water film bound between two charged surfaces, using a finite... 

A novel photolithography-based technique was developed to fabricate a quasi-2D heterogeneous calcite micromodel of representative elementary volume size. The effect of brine-chemistry on the mobilization of capillarity and heterogeneity trapped oil after high salinity water injection was evaluated by using diluted seawater, and seawater modified with calcium, sulphate, and silica nanoparticles. Preliminary brine screening was performed based on modified contact angle experiments under dynamic salinity alteration. The main findings are that the chemical composition of brine impacts both the ultimate oil recovery and its speed. The highest and fastest oil recovery was obtained with diluted... 

Oil polarity is an important property impacting the efficiency of low salinity waterflooding (LSWF). It directly affects fluid/fluid and rock/fluid interactions, controlling the interfacial properties and forces. However, the current findings in the literature on the effect of concentration of polar components on oil recovery by LSWF are contradictory. Therefore, the main objective of this paper is to investigate how the type of non-polar fractions and the concentration of acidic polar oil constituents change the trapped oil saturation at the pore-scale during LSWF. In this regard, we conducted a series of microfluidics LSWF experiments in both secondary and tertiary modes, using clay-free... 

During the low salinity waterflooding (LSWF) of a viscous asphaltic oil reservoir, fluid-fluid interactions have a large influence on the fluid flow, pore-scale events, and thus oil recovery efficiency and behavior. In-situ water-in-oil (W/O) emulsion formation is a consequence of crude oil and brine interfacial activities. Despite the published studies, the pore-scale mechanisms of W/O emulsion formation and the role of injected brine salinity, injection rate, and pore-scale heterogeneity on emulsion formation and stability requires a deeper understanding. To address these, a series of static and dynamic micro-scale experiments were performed. The salinity dependent oil-brine interactions...