Sharif Digital Repository

This study aims to investigate the role of fluid-fluid interactions during low salinity water flooding, using crude oil from an Iranian oil reservoir. To minimize the effects of mineral heterogeneity and wettability alteration, a synthetic sintered glass core was utilized and all coreflooding experiments were performed at low temperatures without any aging process. The effect of fluid-fluid interactions were investigated in both secondary and tertiary injection modes. pH measurements as well as UV-Vis spectroscopy and interfacial tension (IFT) analysis were performed on the effluent brine samples. Results: show that fluid-fluid interactions, mainly the dissolution of crude oil polar... 

The influx of solid or liquid particles of drilling mud into the pores of rock or mud loss phenomenon and clay swelling can sometimes lead to severe productive formation damage and cause to wettability alterations of reservoir rock from hydrophilic to oleophilic. Therefore, designing an appropriate fluid that is compatible with formation fluids and could reduce reservoir damage and increase the productivity of wells is very important. The two main mechanisms of surfactants are reduction of the surface tension and wettability alteration of rock reservoir that are effective in taking the oil. Regarding the importance of the wettability in reservoir productivity, this article is aimed to study... 

Despite previous researches on ion-engineered waterflooding (IEWF), its underlying mechanisms are not fully understood, particularly in presence of additives, like surfactants. This paper concerned with the contribution of Ca 2+ , Mg 2+ , SO 4 2- and Na + into altering wettability of oil-wet carbonate minerals towards water preferred state. As a mechanistic study, an experiment workflow was conducted to probe the impact of ions' concentrations in SW, either with or without sodium dodecylbenzene sulfonate (SDBS) which is an anionic surfactant. At first, contact angle (CA) measurement was carried out to evaluate the degree of wettability reversal upon treating the oil-aged calcite slabs with... 

Low salinity waterflooding (LSWF) is a process in which by lowering the ionic strength and/or manipulation of the composition of the injection water, the long term equilibrium in oil/brine/rock system is disturbed to reach a new state of equilibrium through which the oil production will be enhanced due to fluid/fluid and/or rock/fluid interactions. In spite of recent advances in the simulation of the LSWF at core scale and beyond, there are very few works that have modelled and simulated this process at the pore scale specially using direct numerical simulation (DNS). As a result the effects of wettability alteration and/or Interfacial Tension (IFT) change on the distribution of the phases... 

Wettability alteration analysis form gas-repellent to gas-wet with the aid of chemical agents has been subjected of numerous studies. However, fundamental understanding of the effect of surface tension of liquid on repellency strength, the change in the intermolecular forces due to the adsorption of nanoparticles onto the rock surfaces, and exposure of treated rock in brine are not well discussed in the available literature. In this study, X-ray diffraction, Atomic Force Microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were applied to characterize the treated and fresh samples. Dynamic and static contact angle measurements were then combined with six methods... 

A three-dimensional multi-component transport model in a two-phase oil-water system was developed. The model includes separated terms to account for the dispersion, convection, injection, growth and death of microbes, and accumulation. For the first time, effects of both wettability alteration of reservoir rock from oil wet to water wet and reduction in interfacial tension (IFT) simultaneously on relative permeability and capillary pressure curves were included in a MEOR simulation model. Transport equations were considered for the bacteria, nutrients, and metabolite (bio-surfactant) in the matrix, reduced interfacial tension on phase trapping, surfactant and polymer adsorption, and effect... 

Over 60% of the world's discovered oil reserves are held in carbonate reservoirs, which are mostly naturally fractured. Conventional water flooding results in low oil recovery efficiency in these reservoirs as most of them are oil-wet. On account of negative capillary forces, injected brine cannot penetrate simply into an oil-wet matrix of fractured formations to force the oil out. Wettability alteration of the rock surface to preferentially more water-wet state has been extensively studied using both smart water and surfactants separately. This study aims to study the effects of Mg2+ as one of the most important wettability influencing ions on the wetting properties of oil-wet carbonate...