Sharif Digital Repository

Determining the time of breakthrough of injected water is important when assessing waterflood in an oil reservoir. Breakthrough time distribution for a passive tracer (for example water) in percolation porous media (near the percolation threshold) gives insights into the dynamic behavior of flow in geometrically complex systems. However, the application of such distribution to realistic two-phase displacements can be done based on scaling of all parameters. Here, we propose two new approaches for scaling of breakthrough time (characteristic times) in two-dimensional flow through percolation porous media. The first is based on the flow geometry, and the second uses the flow parameters of a... 

From previous years, water injection was considered as one of the most common methods for enhanced oil recovery. But recently much attention has been paid on the use of low salinity water (LSW) as an enhanced oil recovery fluid. The main mechanism that causes improve oil recovery is wettability alteration to a more water wet state. The change observed in recovery factor during LSW flooding induced from changes in relative permeability and capillary pressure when different levels of salinity are used. However, a few researchers tried to evaluate how macroscopic flow functions depend on the salinity of injected water. To this end, a series oil displacements by water performed on sandstone rock... 

One of the main parameters in modeling of two phase gas and oil flow is an accurate relative permeability functions. This importance will be more intensified when the miscibility condition approaches. In miscible condition due to reduction of interfacial tension between oil and gas phases, parameters of conventional relative permeability functions will change and this changing affects on production results such as oil and gas recovery and also pressure drop along the core. All of the previous studies could not present a unique and consistent model to show the effect of near miscibility condition on relative permeability curves. In this work, these changing of parameters will be investigated... 

Oil reservoir Protection and production optimization requires the proper use of EOR methods. One of the conventional methods of EOR is chemical flooding (for example polymer, alkaline – Polymer, Nano - Polymer and Alkaline - Nano – Polymer flooding) which used for controlling mobility ratio of fluid within a reservoir, altering surface tension between fluids, and change reservoir wettability. On the other hand prediction of oil production in reservoirs during chemical injection processis impossible without having two-phase relative permeability functions and meanwhile, data from the experimental results of these functions are limited.In this study, effect of polymer type and concentration in... 

Gas condensate reservoirs show very complex behavior as wellbore pressure falls below the reservoir fluid dew point pressure and consequently liquid phase appears near the wellbore. Since pressure drawdown is the largest near the wellbore, therefore, this region is the first that experience the liquid dropouts. With continuing the production, reservoir pressures at the other parts of the reservoir fall below the dew point pressure and as a result, condensate appears at these regions. The more the condensate accumulates near the wellbore the more decreasing the gas relative permeability occurs. Condensate accumulating does as a liquid barrier and causes not only decreasing the gas production;... 

So far, many studies have been carried out on the core-scale regarding the effects of hysteresis on the macro-scale properties of systems including fluids and porous rock, however, many issues related to the physics of the problem (especially regarding the way fluids are distributed and the trapping of the non-wetting phase) at the pore-scale need further investigation. In the process of multiphase fluid flow in porous media, hysteresis refers to the dependence of the results of the fluids’ displacements on the history of fluid saturation and the direction of saturation changes (increasing or decreasing). The first step to investigate the hysteresis effect is to determine the amount of fluid... 

Study of two-phase flowin porous media forms a basis for investigating various fluid systemsin the nature and industries. In recent years, more and more researchers use pore-scale mod-els to explore various physical phenomena occurring in complex media such as hydrocarbonreservoirs. After solving the flow equations in pore-scale, this approach can be utilized tocalculate some macroscopic values using particular forms of averaged flow field.In this research, Smoothed Particle Hydrodynamics (SPH) is used to simulate two-phaseflow in pore spaces of two- and three-dimensional porous media. The SPH method is a La-grangian meshless method that is suitable for flows with free surfaces, deformable... 

Mass or large-scale storage of hydrogen, as a clean source of energy, should be conducted in underground formations in order to be used as a reliable energy source at the peak of consumption. In this regard, underground formations such as aquifers and depleted hydrocarbon reservoirs are the most favorable and secured media for hydrogen storage. However, detailed understanding of the flow dynamics of hydrogen-water in these media is critical to maximize hydrogen storage and recovery and tackle the existing uncertainities which exist in the flow functions. To fill this gap, this research aims at a detailed pore-scale investigation of the effect of flow regime, hydrogen compressibility, and... 

A considerable number of engineering applications deal with flow of fluid(s) through particulate porous media. For certain engineering problems, fluid flow may displace and even dislodge the solid particles from the mass where a fluid-particle flow occurs. The complexity of involving processes which should be studied at the scale of moving particles transforms the analyses of these problems towards a difficult engineering task. Characteristics of solid grains such as size and shape and properties of the flowing fluid(s) such as viscosity and surface tension play essential roles in the behavior of fluid-particle systems. Also, when fluid flows through porous media, secondary processes such as... 

Determining the parameters of the porous media and fractures in order to properly understand the processes governing these environments is very important. Traditionally, these parameters are determined in the laboratory. In recent years, with the advancement of computational capabilities, numerical methods have been considered to determine the parameters of the porous media. In the last few decades, the lattice Boltzmann method has been considered by the researchers as a class of computational fluid dynamic methods for simulating fluid flow. The advantages of the lattice Boltzmann method include simplicity in applying to complex media and the ability to simulate different phenomena. In this... 

As the published statistics of prestigious international institutes show, the share of natural gas from the energy basket of the world is rising. This increase is due to some reasons such as decrease in oil reserves, discovery of new gas fields, lower environmental problems, etc. The Islamic Republic of Iran is not an exception of this rule; but also because of huge gas reservoirs that Iran has, it becomes very important for the Iranian government. Hence, research for predicting the behavior of such reservoirs is a necessary need of oil and gas industry.Both thermodynamic and flow behavior of gas condensate fluids are more complicated than other reservoir fluids. Its complex thermodynamic... 

Oil and gas production from oil reservoirs is significantly affected by rock and fluid properties. Relative permeability and capillary pressure are two key flow functions that are used in the numerical modeling of processes related to the porous environment of oil and gas reservoirs at the core scale and above. The use of incorrect relative permeability and capillary pressure curves can lead to inappropriate prediction of the future behavior of the reservoir, which in turn affects future management decisions. Due to the time-consuming nature of obtaining flow functions from the steady state method, history-matching techniques are generally used to estimate these functions as accurately as... 

Gas-oil displacement, when stabilized by gravity forces leads to high displacement efficiency, as manifested in high recovery factor associated with gas-cap drive and gravity drainage. The main objective of this research is improved understanding of drainage behavior and changes in flow properties when the importance of viscous, gravity and capillary forces varies. The influence of interplaying between controlling forces on relative permeabilities is also studied. Another objective of this work is to study effect of wettability on recovery under forced gravity drainage. To study drainage behavior under various dominant driving/resistive forces, a number of forced gravity drainage experiments... 

Today, the Oil industry, much progress has been made in terms of increasing the productivity of reservoirs. In this method, generally one or more fluids are injected into wells to help, extract more oil from the reservoir. Knowledge of the main parameters in this flow of two or three phase fluid in the reservoir is most important. If fractured reservoirs are studied, the multiphase flow are much more complex and require more information about that. Unfortunately, due to the complexity of fractured reservoirs and fluid flow within them, little research has been done on them. The studies about two or three phase flow in fractured reservoirs are classified in two groups, modeling and laboratory... 

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... 

Accurate prediction of relative permeability for various reservoir rocks at various saturation conditions has been of concern for a long time in petroleum industry. Relative permeability is known as one of the most significant parameters in simulation of actual multi-phase flow through porous media during life-time of a hydrocarbon reservoir. In addition, it plays important role in oil production and well completion. Direct experimental measurement in order to determine relative permeability of porous rock has long been recorded in petroleum related literature. However, empirical methods for determining relative permeability are becoming more widely used, particularly with the advent of... 

An experimental study was conducted to investigate the reduction of relative permeability caused by salt precipitation. Series of isothermal sand pack flood experiments were conducted on a sand pack composed of several minerals and relative permeability of the involved phases were determined. This compose was taken south of Iranian reservoir properties. A stainless steel sand-pack of 2.5cm internal diameter and 19.2 cm long was designed and built for experimental procedure. There are is different methods to determine relative permeability of porous media, According to available facilities in the lab and objective of this study unsteady state have been chosen to determine relative... 

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... 

Productivity reduction of oil and gas wells due to mud induced permeability impairment is one of challenging problems in drilling and production studies. This phenomenon is of prime importance in fractured reservoirs in which high permeability fracture networks act as conduits for feeding gas or oil from a tight matrix to the wellbore. Up to now, many experimental and modeling investigations have been done in formation damage in conventional reservoirs. But in spite of large contribution of fractured reservoirs in total hydrocarbon reserves, there is very little work reported in the literature investigating formation damage in such reservoirs. In this thesis, the effective parameters in... 

In oil industry, increment of drilling mud viscosity is of great importance. Water based polymers are widely use as drilling fluid to achieve this goal. Formation damages can be occurred by invading polymer solution into the formation in different ways such as scale and precipitation. These damages appear in different shapes such as reduction in relative permeability and productivity index reduction. In this study we have proposed, designed and fabricated a novel device, called sand pack, to measure the damage of the reservoir which enable us to calculate relative permeability and recovery factor by means of pressure difference and flow rate. Using this lab-scaled device we have measured...