Sharif Digital Repository

Abstract original image Smart Enhanced Oil Recovery Process using Core–Shell Nanoparticles: The cover image denotes schematically the enhanced oil recovery process by flooding using an aqueous dispersion of core–shell nanoparticles made up of protected polyacrylamide nanostructures (PPNs). Y. Tamsilian and his colleagues at Sharif University of Technology (Iran) and the Institute for Polymer Material (POLYMAT, Spain) demonstrated the synthesis of polyacrylamide nanoparticles protected with a hydrophobic polystyrene shell by using a one-pot, two-step inverse emulsion polymerization technique, where the polystyrene shell was created by surface polymerization. The presence of the hydrophobic... 

Biodegradation of petroleum hydrocarbons in salt medium (SM) containing sea water by Pseudomanas sp. was investigated. Different oil hydrocarbons such as n-decane, benzene, naphthalene, paraffin, paraffin + vaseline, paraffin + kerosene, and fuel oil were used as carbon sources. Cell growth (OD) and COD were measured for evaluation of oil biodegradability. The effect of inorganic and organic nitrogen sources on COD removal revealed a 95% and 75% reduction of COD for inorganic and organic nitrogen sources, respectively  

This work concerns a fundamental understanding of how heterogeneities induced by flow barriers and connate water affect the displacement efficiency of polymer floods, which has rarely been studied in the available literature. Here, a series of water/polymer injection experiments to heavy oil performed on five-spot glass micromodels containing randomly distributed shale structures is presented. It has been found that macroscopic efficiency of polymer flooding majorly depends on flow barriers distribution/configuration; shale content and geometrical characteristics; presence of connate water and wettability of medium. Microscopic pictures revealed that the main parts of connate water were... 

Steam-assisted gravity drainage is one of the most promising strategies to develop huge heavy oil and bitumen accumulations. Like the other thermal processes, this method aims at reducing oil viscosity by increasing the temperature. But in an economical point of view, it requires a great volume of steam for injection. Moreover, early breakthrough of steam and high steam-oil ratio makes it uneconomical, especially in long production time. In this study, a new method, two wells cyclical steam-assisted gravity drainage is compared with a conventional steam-assisted gravity drainage process. Well configuration in two wells cyclical steam-assisted gravity drainage is the same as the... 

A novel mathematical-based approach is proposed to develop reliable models for prediction of saturated crude oil viscosity in a wide range of PVT properties. A new soft computing approach, namely least square support vector machine modeling optimized with coupled simulated annealing optimization technique, is proposed. Six models have been developed to predict saturated oil viscosity, which are designed in such a way that could predict saturated oil viscosity with every available PVT parameter. The constructed models are evaluated by carrying out extensive experimental saturated crude oil viscosity data from Iranian oil reservoirs, which were measured using a "Rolling Ball viscometer." To... 

The performance of CO2 injection into a semi-heavy oil reservoir was investigated at reservoir conditions, using highly permeable sandstone in a complete series of PVT tests and coreflooding experiments. Analysis of involved parameters such as: injection rate, injectant type and reservoir pressure were also considered. Oil viscosity reduction and oil swelling are the most influential mechanisms of enhanced oil recovery in this process. The results demonstrated that CO2 injection would decrease the interfacial tension for the high permeable medium in the absence of capillarity, but this reduction may not improve the recovery drastically. One of the main important aspects of this work is the... 

The performance of CO2 injection into a semi-heavy oil reservoir was investigated at reservoir conditions, using highly permeable sandstone in a complete series of PVT tests and coreflooding experiments. Analysis of involved parameters such as: injection rate, injectant type and reservoir pressure were also considered. Oil viscosity reduction and oil swelling are the most influential mechanisms of enhanced oil recovery in this process. The results demonstrated that CO2 injection would decrease the interfacial tension for the high permeable medium in the absence of capillarity, but this reduction may not improve the recovery drastically. One of the main important aspects of this work is the... 

The disposal of polychlorinated biphenyls (PCBs) as persistent organic pollutants from the environment has been normally performed by isolation from soil or water because of their biological activity and toxic potential. In the present investigation, catalytic hydrodehalogenation was used to detoxify PCBs-contaminated transformer oil. All reactions were directed on an oil containing 11.09 wt% of PCBs utilizing palladium supported on multi-walled carbon nanotubes (Pd/MWCNTs). The amount of hexa-chlorine homologues reduced considerably from 5.07% to less than 800 ppm utilizing HDC at the atmosphere of argon. Moreover, the amounts of long half-lives and bioaccumulative congener of PCB 153... 

Change occurrence during project's life cycle and its impact on project's success is common concern of all parties in projects. Hence, predicting and managing them to mitigate their negative outcomes is critical. This study offers categorization of changes types, causes and effects arise in Iranian projects and investigates the most prevalent ones through conducting a survey. Findings demonstrate that schedule, information and time are the most frequent type, cause and impact of changes, respectively  

The effects of CO2 and salt type on the interfacial tension (IFT) between crude oil and carbonated brine (CB) have not been fully understood. This study focuses on measuring the dynamic IFT between acidic crude oil with a total acid number of 1.5 mg KOH/g and fully CO2-saturated aqueous solutions consisting of 15,000 ppm of KCl, NaCl, CaCl2 and MgCl2 at 30 °C and a wide range of pressures (500–4000 psi). The results of IFT measurements showed that solvation of CO2 into all the studied aqueous solutions led to an increase in IFT of acidic crude oil (i.e., comparison of IFT of crude oil/CB and crude oil/brine), while no significant effect was observed for pressure. In contrast, the obtained... 

Improving oil recovery and decreasing greenhouse gas emissions are two important attractive features of CO2-enriched water injection into oil reservoirs. Regarding these unique features, the main objective of this study was concentrated to evaluate the swelling behavior of crude oil as a fundamental mechanism of carbonated water (CW) flooding. To achieve these goals, the swelling and Bond number of light and heavy crude oils (namely LCO and HCO, respectively) are measured and compared to each other. The results obtained from the measured swelling factors of crude oil/CW show some complicated behaviors. That is, as temperature increases the swelling factor decreases at low pressure... 

To meet stringent emission standards stipulated by regulatory agencies, the oil industry is required to bring down the sulfur content in fuels. Oil supplies 38% of the worldwide energy, and as the light oil is limited and meanwhile the energy demand is increasing, it is a must to use heavy crude oil and therefore desulfurize it to meet environmental standards. As it is not feasible to desulfurize all the sulfur containing compounds of heavy crude oil by the existing methods (such as hydro-desulfurization) we have focused on biodesulfurization of heavy crude oil. We have isolated the first native fungus which has been identified as Stachybotrys sp. and is able to remove sulfur and nitrogen... 

The oil exporting countries have experienced a relatively continuous fall in GDP per capita over the last 30 years. This is in spite of benefiting from a more than average of the rest of the world investment rate. The findings of this paper, report a lower level of financial development for the oil economies when compared with the rest of the world. We will show in this paper that the higher rate of investment of the oil economies can be explained mainly by the oil revenues and surprisingly, financial development has a net dampening effect on investment for these economies. The paper also shows that the weakness of financial institutions, contributes to the poor performance of economic... 

Although most heavy oil reservoirs contain discontinuous shaly structures, there is a lack of fundamental understanding how the shaly structures affect the oil recovery efficiency, especially during surfactant flooding to heavy oils. Here, an experimental study was conducted to examine the effect of discontinuous shales on performance of surfactant flooding by introducing heterogeneities to represent streaks of shale in five-spot glass micromodels. Results show that oil recovery in presence of shale streak is lower than in its absence. Based on the authors' observations, the presence of flow barriers causes premature breakthrough of injected fluids and also an unstable displacement front. As... 

This paper concerns on experimental investigation of biopolymer/polymer flooding in fractured five-spot systems. In this study, a series of polymer injection processes were performed on five-spot glass type micromodels saturated with heavy crude oil. Seven fractured glass type micromodels were used to illustrate the effects of polymer type/concentration on oil recovery efficiency in presence of fractures with different geometrical properties (i.e., fractures orientation, length and number of fractures). Four synthetic polymers as well as a biopolymer at different levels of concentration were tested. Also a micromodel constituted from dead-end pores with various geometrical properties was... 

Many bitumen reservoirs contain shale layers of varying thickness, lateral extent, and frequency. These shale layers, depending on their size, vertical and horizontal locations, and continuity throughout the reservoir, may act as a flow barrier and severely reduce vertical permeability of the pay zone and slow down the steam-assisted gravity drainage steam chamber development. Therefore, to improve productivity in these reservoirs, understanding of the effects of reservoir heterogeneities has become necessary. This work presents numerical investigation of the effects of shale barriers on steam-assisted gravity drainage performance when applied to produce mobile heavy oil. The most concern of... 

Phase behavior of active crude oil/alkaline was systematically studied in the presence of cosolvents. For this purpose, several factors have been considered: alkaline concentration, oil concentration, and type of brine. The best composition was used to generate emulsion for rheology and displacement tests. Furthermore, precipitation of alkaline was eliminated by its synergy with EDTA. Next, rheology of emulsion was analyzed by which a Power law model was developed that indicates non-Newtonian behavior of emulsion. Moreover, the viscosity of emulsion was reduced by the addition of cosolvent as well as by the increase of alkaline concentration. Finally, the best formulation (containing... 

Enhanced oil recovery (EOR) methods assisted by gravity drainage mechanism and application of sophisticated horizontal wells bring new hope for heavy oil extraction. Variety of thermal and non-thermal EOR techniques inject an external source of energy and materials such as steam, solvent vapor, or gas through a horizontal well at the top of the reservoir to reduce in-situ heavy oil viscosity. So, the diluted oil becomes mobile and flows downwards by gravity drainage to a horizontal producer located at the bottom of the reservoir. In this paper, a sector model of an Iranian fractured carbonate heavy oil reservoir was provided to simulate and evaluate capability of some EOR techniques such as... 

In this work, the effect of brine salinity on water-in-oil emulsion flow performance in porous media is studied as it imposes a significant challenge to oil production in the petroleum industry. A crude oil sample from an Iranian oilfield and synthetic brine with different salinities (40-140 g/L salt) are used. The results show that the emulsion viscosity and interfacial tension increase slightly with salinity, while they do not considerably affect the flow behavior. The emulsion stability analysis shows that larger w/o emulsion droplets are formed for higher brine salinity, which potentially block more pore spaces through straining and interception mechanisms. This phenomenon resulted in...