Sharif Digital Repository

Evidently, environment contamination by water insoluble chemicals present at the industrial wastes could bring about catastrophic consequences to the biosphere. Biological based cleaning technologies are commonly considered as a practical remedy to remove these contaminations. In fact, these techniques are founded on the ability of certain microorganisms to degrade the contaminants. It is crystal clear that the availability of contaminants to the microorganisms is an essential parameter determining the final efficiency of the biodegradation process. In practice, the limited solubility of the contaminants in the aqueous phase leads to mass transfer constraints which consequently, decrease the... 

Relative permeability is an important factor that controls the two phase fluid flow in porous media. The use of carbon dioxide in enhanced oil recovery methods is common. But the question is, how does the carbon dioxide affect the relative permeability curves? In this thesis, the CO2-oil relative permeability is measured in CO2 flooding process with unsteady state method. For this purpose, the core flooding apparatus is used and the results are compared with N2-oil relative permeability in N2 flooding. The results of comparison show that oil relative permeability in CO2 flooding is higher than N2 flooding. Reduction of Interfacial tension and oil viscosity, solubility of CO2 in oil and oil... 

There are a lot of Fractured reservoirs around the world that have large portion of oil production. These reservoirs have complex structure and fractures have important role in production but the remaining oil in matrix causes that the oil recovery decreases. One of the most important factors in these reservois are wettability. Because most of the fractured reservoirs are oil wet and water injection process in these reservoirs are not effective and chemical EOR methods such as surfactant flooding method is used. Surfactant improve oil recovery by two reasons: 1- reduction of interfacial tension between oil and water . 2-Wettability alteration of matrix. The porpose of this project is... 

After primary and secondary recovery processes more than 50 percent of oil remains in reservoirs. Therefore for more recovery from these reservoirs, methods of enhanced oil recovery should be applied.In this paper the effect of nanoparticles of SiO2 in size of 14 nm, on wettability is investigated. Using this nanoparticle, the wettability of carbonate rock in reservoirs could be changed and alter from oil-wet or mix-wet to water-wet. To assess this, hydrophilic changes of sandstone core and carbonate core are studied using the contact angle test. The same test is done on the carbonate core saturated with brine and oil that had received injection with brine and nanoparticles of SiO2 with two... 

Today, due to limited number of light oil reservoirs, enhanced recovery from heavy oil reservoirs is taken into consideration. During the early production from heavy oil reservoirs, due to high viscosity, only a small amount (about 5%) of the oil can be produced; also after water injection operation due to unfavorable mobility ratio of water and oil, sorely more than about 10% of the original oil can be produced. On the other hand, fractured reservoirs represent about 20% of the world's oil reserves, while over 60% of the world's remaining oil reserves are in fractured reservoirs. Water flooding process leaves very high amounts of oil as remaining oil in these reservoirs too. One of the... 

Interfacial Tension (IFT) as a main parameter for gas flooding efficiency in oil reservoirs depends highly on pressure, temperature, and composition of the reservoir fluids. Therefore, it is important to measure this parameter at real reservoir condition for successful field development plan. In this study, an axisymmetric drop shape analysis (ADSA) has been utilized to measure the equilibrium IFTs in crude oil-flue gas systems at different temperatures and pressures. Moreover, minimum miscibility pressures (MMP) of crude oil/flue gas and crude oil/N2 systems at different temperature levels are determined by applying vanishing interfacial tension (VIT) technique. Then, the effect of oil... 

There is increasing evidence that injecting modified brines has a significant impact on the amount of oil recovered, but the exact mechanism by which this occurs is an unsettled issue, and is supposed to be a cause of the complex interactions occurring between the phases insitu. In this thesis, surface chemistry of smart water has been investigated. Fluid/solid and fluid/fluid interactions for Bangestan crude oil in tfhe presence of designed solutions and a set of dilutions of Persian Gulf seawater have been studied and compared. Fluid/solid interactions were investigated through wettability studies. Impact of salinity and ionic composition on this interaction was measured through contact... 

Minimum miscibility pressure (MMP) is a key parameter for successful gas injection process in the oil reservoirs for more oil recovery. This parameter is critically dependent on the reservoir condition such as temperature, reservoir and injection gas composition. There are many techniques used in the literature for MMP measurement. Vanishing interfacial tension (VIT) has been proposed recently and was used successfully to predict the MMP through pendant drop technique. This technique is used in this study to measure the MMP for Nitrogen/Carbon dioxide and water in oil emulsion fluids; then compare it to the original crude oil without water droplets. This would demonstrate the effects of... 

This research was done for feasibility evaluation and understanding correct microbial enhanced oil recovery(MEOR) procedure for carbonate reservoirs. With the aim of cost reduction and possible activation of smart water mechanisms, sea water used as a base for MEOR process. Two biosurfactant producing strains were isolated from oil contaminated water and soil, and one halotolerant strain, from sea water. Optimization of biosurfactant yield was conducted and two new definitions for optimum point, by considering economical and technical facts, were proposed. Partial characterization of produced biosurfactant was carried out through FTIR and NMR analysis and the produced biosurfactant was... 

Foamy oil reservoirs and reservoirs which have water in oil emulsions have some difficulties through production with water based enhanced oil recovery techniques. Study of IFT of these oils may improve production of these reservoirs, especially for water based techniques which are most popular techniques. In this study, IFT of these oils were studied in reservoir condition. Effects of pressure, temperature and water composition were investigated. These effects were studied through Pendant drop technique and VIT apparatus  

Increasing the global demand for energy and decreasing the production rate of oil reservoirs have forced the oil companies to focus on enhanced oil recovery (EOR) extensively. This paper summarizes the design, reservoir simulation, and results of different gas injection scenarios in one of the Iranian complex oil reservoirs. This complex reservoir is located in the south west of Iran and is made up of sandstone, limestone, and dolomite layers. It is an under saturated reservoir with no gas cap but with a strong aquifer. Oil production has started in 1977, but due to strong aquifer the production is still in the plateau period. In this study, by simulation, it is estimated that natural... 

The assessment of fluid transport in porous media is the main subject in oil reservoirs to understand the oil recovery efficiency. The efficiency of Enhanced oil recovery (EOR) processes depends on the surface properties and wetting behavior of oil reservoir rocks which are also affected by the electrokinetic behavior of solid part of the porous rock. Streaming potential measurement is one of the techniques to determine the electrokinetic properties. The streaming potential measurements using electrodes have recently been introduced in oil field applications and there are still significant uncertainties during the measurements and interpretation of streaming potential results. The Primarily... 

VAPEX is a relatively new EOR process for the recovery of heavy oil. In this process solvent is used to form a vapor chamber within a reservoir. Vapor dissolves in the oil and diluted oil drains by gravity to a horizontal production well. The essential features of this recovery mechanism have been discussed in this study. Furthermore, a semi-analytical and a simulation study of VAPEX process have been performed on a specified Iranian heavy oil reservoir (such as Kuh-e-Mond). The aim of this study is to investigate an exponential functionality (correlation) witch incorporates all physical parameters that affect the production rate of VAPEX process in dimensionless form. The adjustable... 

Hydrocarbon reservoir management and development as well as planning of enhanced oil recovery (EOR) processes are based on the reservoir dynamic model. Thus, successful implementation of EOR scenarios greatly depends on the quality of the dynamic model and accuracy of the associated parameters in order to correctly describe fluid flow through porous media. First, a dynamic model is constructed based on the prior knowledge. However, because of the various types of error during model building, the prior model is not so accurate and perfect. Accordingly, new observation data, such as production and 4D seismic data, are utilized to calibrate the prior model and characterize the reservoir under a... 

Excessive water production in highly heterogeneous mature reservoirs (water flooded or affected by water zones) leads to increased production costs. Water production causes sediment formation, creation of corrosion, water treatment and disposal, and finally due to the inefficiency of production, it leads to closure of the well.Among the methods introduced to reduce water production, the use of polymers and gels as an affordable and effective method has been widely used in enhanced oil recovery processes. The main mechanism in this method is blocking or limiting the major paths of water flow (fractures or high permeability zones) and thereby increasing sweep efficiency in water injection.... 

Asphaltenes are a polydisperse mixture of the heaviest and most polarizable fractions of the crude oil. They are defined according to their solubility properties as being soluble in aromatic solvents but insoluble in light paraffin solvents. Asphaltenes are usually responsible for many problems like wettability changes of the reservoir rock, pore clogging in the reservoir porous matrix and fouling in wellbore tubing and production surface facilities. Most of the studies in the literature, addressing the asphaltene precipitation and deposition (APD), are investigating natural depletion or gas injection process such as CO2 flooding. These studies show that asphaltene deposition and... 

Microbial enhanced oil recovery (MEOR) is a collection of techniques that utilize microorganisms and their metabolic products to improve the recovery of crude oil from reservoir rock. From the advantages of this method, independency to the oil price and environmental benign can be mentioned. Many mechanisms have been proposed to contribute on MEOR, but still there is no enough knowledge about the mechanisms that causes inabilities in manipulating the process to get more oil production.
In the present study, the effect of a native type of bacteria, Enterobacter cloacae, on the glass surfaces wettability which were aged in expose of model oil with different asphaltene concentration was... 

Considering the drastical increase of greenhouse gases in the atmosphere, especially carbon dioxide, reduction of these gases seems necessary to combat global warming. Fossil fuel power plants are one of the main sources of CO2 emission. In this paper, CO2 capture from a natural gas fired steam cycle power plant using oxy-fuel combustion technology is studied. The Integrated Environmental Control Model (IECM) developed by Carnegie Mellon University was used to evaluate the effect of this capture technology on the plant efficiency and economic parameters of the system. Since the oxygen production plant, CO2 capture and transport are cost and energy intensive, the cost of electricity generated... 

Gas injection is a well-known enhanced recovery method which can improve recovery using two different displacement processes, miscible and immiscible. Typical non-hydrocarbon gases which have been utilized in these processes are carbon-dioxide and nitrogen. These gases are usually injected separately and have been rarely utilized together as a tertiary recovery process.
In this paper, we have focused on sequential carbon-dioxide and nitrogen gas injection as a novel EOR method. The periodic injections of carbon-dioxide and nitrogen have been repeated for six injection pore volumes. Sensitivity analysis of injection pressure, injection volume and injection rate have been also investigated... 

Gas injection processes are considered as the second largest Enhanced Oil Recovery processes after thermal processes. In Dealing with the problems of Continuous Gas Injection (CGI) processes, the substitute method of Water Alternating Gas (WAG) is gaining ever increasing attention in field applications. The Hybrid method has the advantages both CGI and WAG processes. Laboratory studies of gas injection methods to show the optimum method and the effect of pressure on the performance of this method is the main objective of this project. Results obtained from these tests can be used in the Enhanced Oil Recovery scenarios for this reservoir. In this project, experiments for Continuous Gas...