Sharif Digital Repository

Among different enhanced oil recovery (EOR) methods, low salinity waterflooding (LSWF) has been attractive to researchers because of its relative simplicity and lower environmental problems compared to other conventional EOR methods. Numerous researchers have attempted to find the main cause of the low salinity effect (LSE). According to previous studies, several experimental techniques have been proposed for predicting LSE and screening potential field candidates. However, there is a lack of a systematic investigation of all (or even some of) the methods to compare and determine their LSE predictive capability. Predictive capability development is essential because it saves costs and time... 

Recent studies have shown that the injection of low-salinity water would enhance the oil recovery factor for both the core scale and the field test. The evidence obtained from laboratory studies showed that the control of salinity and the composition of injected water has successfully affected the oil release, hence enhancing the oil recovery efficiency. In this method, by changing the type and amount of dissolved ions in the injected water, the water/oil/rock interactions are altered. Based on this, extensive studies have been focused on the mechanisms for the trapped oil release at the pore scale. Several mechanisms have been proposed to explain this phenomenon, which can be divided... 

Loess with a dispersion potential is one of the problematic soils of Iran. This study aims to investigate the impact of dispersion potential on the water flow in a three-phase medium and determine the effect of salinity on the stability of an unsaturated railway embankment by employing the soil-water retention curves of the materials. To satisfy this objective, the natural dispersive loess of the Chabahar region is desalinated in this study and the hydraulic properties of both saline and desalinated soils are comprehensively investigated. First, the soil-water retention curves of the materials are measured through the filter paper test method. Afterward, the saturated hydraulic conductivity... 

Based on numerous laboratory and field evidence, low-salinity waterflooding or engineered salinity waterflooding can lead to enhanced oil production. According to the literature, the mechanisms involved in this process can be divided into two general categories: fluid-fluid interactions and solid-liquid interactions. These mechanisms are caused by intermolecular and electrostatic forces at the rock and fluid interfaces. The most important controlling factor of the electrostatic forces is the concentration of ions at/near fluids-rock interface. Therefore, improving the concentration of ions causes a shift in wettability toward a more water-wetting state, eventually leading to increased oil... 

Due to anthropogenic activities and climate change, Lake Urmia, one of the largest hypersaline lakes, is exposed to desiccating. The increase in salinity in this lake up to more than 400 p.s.u has endangered the ecology of this lake. In this study, a three-dimensional, unstructured grid and finite volume model FVCOM has been developed to investigate Lake Urmia's hydrodynamics, salinity, and water temperature over the year 2016. Some of the model inputs were lake bathymetry, meteorological data (including air temperature and pressure, wind speed and direction, short-wave and longwave radiation), precipitation, evaporation, river flux, salinity, and temperature. The model was calibrated... 

Recent experimental studies have demonstrated that the lowering of brine could alter the wettability of the oil-brine-rock systems from an oil-wetting state toward a more water-wetting state. This so-called “Low-salinity effect” (LSE) is one of the main effects of the enhanced oil recovery technology based on low-salinity waterflooding. “Double layer expansion” (DLE) in the thin brine film is proposed as the principal mechanism of this phenomenon. Nonetheless, the role of the electrical behavior of the oil/brine and rock/brine interfaces on the kinetics and dynamics of this process is not well understood. Moreover, since most of the previous works have either dealt with a thin film at... 

Low salinity water flooding (LSWF) is a relatively new EOR method in which low salinity or modified ionic composition water is injected into the reservoir to alter its wettability toward a more water-wettable state to accelerate oil recovery. Ease of field deployment and relatively low cost, as well as laboratory results confirming the positive effect of this method in improving the oil recovery factor, have made this technique attractive in the oil industry.Despite the many advantages of this method, overcoming the mixing between low and high salinity water which occurs due to a high mobility ratio between these two fluids is essential because it negatively affects the efficiency of LSWF.... 

Gorgan Bay and Miankaleh Wetland have been exposed to various environmental risks in the past years due to the decrease in the Caspian water level and the subsequent decrease in the water level of these water bodies. 2 channels, Chapgoli and Ashuradeh, are the only ways connecting the Gulf with the Caspian Sea. If the water level of the Caspian Sea and the Gulf continue to decrease, these 2 channels will be completely blocked and the connection between the Gulf and the sea will be completely closed. Due to the low depth of the bay and high evaporation on this water body, the blockage of these 2 channels will eventually lead to drying up of the bay or changing the flora and fauna of the area.... 

Many industries such as olive oil mills, petroleum refineries, petrochemical plants and oil field operations generate saline wastewaters containing phenol. The aerobic moving bed biofilm reactor (MBBR) was investigated in this work in order to assess its performance for the degradation and chemical oxygen demand (COD) removal of phenol as the sole substrate from saline wastewater. The effect of inlet concentration of phenol (200–1200mg/L), hydraulic retention time (8–24 h), inlet concentration of salt (10-70gr/L), organic shock loading, hydraulic shock loading and salt shock loading were evaluated on the performance of two 10-liter MBBR seeded with mixed culture of active biomass... 

Gas injection is one of the most common methods to enhance oil recovery. But due to the low viscosity and density of gas, viscous fingering and gravity over ride usually happens which lead to reduction of gas injection performance to oil production. Foam injection is one of the techniques that has the potential to improve oil production by increasing. Foam apparent viscosity is higher than gas and its liquid which is made from it. So it can increase sweep efficiency and enhance oil recovery. However, presence of oil can destabilize foam. Beside, salinity has different effects on foamability and foam stability. Foam stability in high saline environment is a challenge. Therefore, the stability... 

Inorganic scale deposition has been found to affect many industrial processes,including water injection into the oil reservoirs. Major formation damage because of incompatibility of high sulfate ion content of seawater with formation water containing calcium ion results in formation damage and production decline.In this study, several simultaneous techniques are utilized for qualitative and quantitative analysis of calcium sulfate scale to get more insight into the damage of formation during smart water flooding at micro and Nano scales. In the experimental section, calcium sulfate deposition due to the mixing of the formation water and seawater samples was investigated using the dynamic... 

Enhancing oil production from fractured reservoirs is challenging. The flow characteristics observed in naturally fractured reservoirs are complicated due to interaction between the two different flow domains: fracture and matrix. Spontaneous imbibition is one of the most important recovery processes in water-wet fractured reservoirs. Oil cannot be spontaneously produced from oil-wet rocks, unless the capillary pressure barrier between fracture conduits and matrix is overcome. The flow characteristics in fractured systems thus relate to the wettability of the rocks. Low salinity water injection has been widely studied as a method of enhancing oil recovery in recent years. However, its impact... 

Oil composition plays an undeniable role on the low salinity water flooding (LSWF) efficiency. This property directly affects the kinetics of wettability alteration through electrostatic interactions and interfacial tension (IFT). For instance, mixing in stagnant zones through a thin water film is considered as one of the most important diffusion controlled phenomenon which is goverened by Non-Fickian solute transport model. The major two potentials controlling the solute transport in thin film are salinity gradient and electrostatic potentials, which can be affected by oil composition and surface charges. This study aims to investigate the effect of oil composition on low salinity... 

Considering the water tensions, especially in the Middle East, water resources for the implementation of water-based EOR methods are shown to be critically limited. Water sources such as industrial wastewater hold great potential to be used for this purpose due to their significant available volume and the need for their disposal because of environmental regulations. In this research, the potential of injecting industrial wastewater, as low-salinity water, in an Iranian carbonated oil reservoir has been thoroughly investigated by conducting core-scale experiments. In this regard, we also developed a guideline for designing various types of experiments to use this "unconventional" injection... 

Wettability of reservoir rock is one of the effective parameters in determining the mechanisms of production and consequently the amount of residual oil inside the porous media. In addition, the salinity of injected water is important factor in the recovery of reservoir oil in waterflooding.On the other hand, the role of the hysteresis on the residual oil saturation as well as the flow functions such as relative permeability curves is very important. In this project, the effects of reservoir wettability and injected water salinity on the hysteresis and residual oil saturation in two-phase water-oil flow systems are studied. Core-scale experiments were carried out using sandpacks and were... 

Low salinity water flooding (LSWF) as an efficient enhanced oil recovery (EOR) technique is proved to affect both, fluid-fluid and rock-fluid interactions to potentially release the trapped oil from the porous rock. Despite more than one decade of extensive research works on the low salinity water effect (LSWE), there are still many parameters to be studied for very complex cases. Therefore, in the first part of the experimental study of the dissertation, a systematic investigation on the effect of the initial wetting state (water-wet or oil-wet) of pure calcite is conducted to study the importance of fluid/fluid and fluid/rock interactions for LSWE investigation. In the case of initially... 

It is believed that the carbon dioxide emissions are likely to be the dominant drivers of climate change over the coming century. Geological sequestration in saline aquifers is a potential technology for mitigating carbon dioxide emission in atmosphere. In this study, computer simulation is combined with experimental design to perform sensitivity analysis and estimation of carbon dioxide sequestration in saline aquifers. For this purpose, horizontal permeability, vertical to horizontal permeability ratio, porosity, depth, pressure gradient, temperature gradient, water salinity, formation thickness, diffusivity coefficient, dip, irreducible water saturation, water Corey exponent, gas Corey... 

The main objective of this research was to evaluate the application of a new strain of Brevundimonas naejangsanensis which is newly identified sulfate-reducing bacteria (SRB), in bioremediation. A laboratory scale packed bed reactor (PBR) was fabricated and operated to study the new bacteria’s feasibility on SO_4^(2-) reduction. The reactor was packed with polyurethane foam cubes and operated under different feeding and operating conditions of HRT, COD/SO_4^(2-) ratio and salinity. A maximum SO_4^(2-) reduction of 73.6% was achieved in the PBR when operated at an HRT of 12 h with SO_4^(2-) concentration of 670 mg/L, COD/SO_4^(2-) ratio of 1 and salinity of 3%. The results show that this... 

Due to the decrease in oil reserves in the world, increasing population and the growing demands for oil consumption in the world, increasing the oil recovery from oil reservoirs has become more important. Increasing the amount of oil production efficiency by using low salinity water/modified salinity water has been highly appreciated during the last two decades. Low-salt water is a new method, due to its advantages such as low cost, simplicity of operation and low environmental hazards. It is believed that low salinity water can alter the rock wettability from a more oil-wetting state to a more water-wetting state. In order to be able to predict the performance of low salinity water... 

The Low salinity water flooding is one of the important methods of secondary and tertiary oil production in which many expert petroleum-production engineering working on it in recent two decades. There are some basis mechanisms for low salinity method presented in the literatures including fine migrations, alkaline flooding, multicomponent ionic exchange, electrical double-layer expansion and pH-driven wettability alteration. The main approach is generating low salinity mechanism especially wettability alteration in OpenPNM framework. OpenPNM is a python base framework developed by Jeff Gostick for porous media modeling. OpenPNM has paved the way for extracting pore network models (PNM) from...