Sharif Digital Repository

Viscosity is one of the most important properties used in simulating and optimizing transportation design and hydrocarbon reservoirs simulation. In this work, a new model based on the friction theory was used to correlate the viscosity for six different live and dead oil samples taken from the south of the Iranian oil region. As expounded by other researchers, in the friction theory, an equation of state is used to express the intermolecular viscous interactions. In model presented in this work, the standard cubic equations of state such as the SRK and PR were used to correlate the viscosity data for the samples under investigation. In the new model, the effect of critical viscosity on the... 

Synthetic based fluid has been introduced since 1990 as an alternative to conventional oil-based fluid, which, like oil-based mud, is effective wherever the use of water-based mud is problematic. This type of fluid with similar performance to oil-based mud is environmentally acceptable and the safety of working with this fluid is higher for drilling rig personnel. cutting drilled with synthetic base fluid can be discharged into ocean and sea waters, and this can reduce the total cost of drilling compared to oil-based mud because there isn't need to transport the cutting to offshore and dispose of them and consequently drilling is reduced. In terms of safety, these fluids reduce the risk of... 

Prediction and prevention from asphaltene deposition is an essential topic in oil production systems that can enormously increase oil production costs. Many studies have been done to understand and predict the behavior of asphaltene-containing oils. Prediction and investigation of asphaltene precipitation are required to predict the asphaltene deposition problem. Changes in temperature, pressure, and composition can cause precipitation, and these changes are inevitable during production. This dissertation compares the thermodynamic models that can simulate asphaltene precipitation. Firstly, A comprehensive review was done to extract the maximum amount of experimental data from the literature... 

Since the beginning of oil, gas and gas condensate production, the prediction of the formation of mineral scales in different operating conditions has been a serious challenge. Mineral scale are solid particles that are separated from the free water in the reservoir due to changes in the production conditions in terms of temperature and pressure or the fluid composition of the production fluid of reservoir, and there is a possibility of their deposing on the wall of the well column and in the production system, where The way of production from reservoirs faces serious risks. free water, which is permanently entering the pipeline, contains all kinds of salts in the structure of the fluid... 

There is a need from the natural gas and energy industries to seek for an economically attractive way of converting remote gas reserves into transportable products, such as high quality fuels or petrochemicals. A possible way for the conversion of natural gas to middle distillates is based on a three-step process. Firstly, production of syngas from natural gas. Secondly,catalytic conversion of syngas into hydrocarbons, mostly parafins from C5 to C100. (Fischer-Tropsch (F-T) synthesis). Thirdly, hydrocracking of the heavy paraffinic hydrocarbons to middle distillates. The F-T synthesis step is highly exothermic. In order to control the temperature within the reactor, when considering high... 

The behavior of biomolecules in mixtures is affected by the presence of electrolytes. For instance, in the presence of an electrolyte, solubility of most biomolecules like proteins,peptids and amino acids can be increased or decreased. As a biomolecule, urea is a protein denaturant and influences protein folding and protein-DNA binding. The presence of ions can affect the interactions between urea and water In this thesis, experimental data of density and electrical conductance of aqueous solutions of urea-NaCl were obtained at different physical conditions. Density measurement experiments were carried out at different temperatures from 20-40 oC. Apparent and infinite dilution molar volumes... 

Nowadays oil and gas industry has taken the pulse of world energy. Different countries of the world are trying more and more to explore and produce this black gold. To do so these countries has gained many experiences and even gone to seas and oceans to find oil and gas. In the process, they has faced with a new phenomenon called gas hydrate. The phenomenon which was unknown and destructive at first after excessive research, today is even called as the future energy source of the world. But what we discussed in this study is hydrate as a problem in oil and gas industry. Gas hydrates are formed in favorable temperature and pressure condition (low temperature and high pressure) in the... 

Always, understanding the properties of crude oil and related phenomena of that has been noticeable matter. Surface tension is one of the important fluid properties and the evaluation of that is essential in oil industry especially in enhanced oil recovery method (EOR) and transport of crude oil by using emulsions.
In this research, interfacial tension (IFT) was measured via pendant drop method. The effect of three parameters was investigated on IFT for creating of stable oil/water emulsion. These parameters were temperature, concentration of surfactants, and salinity. They were varied between 25-65 ᵒC, 0.05-0.2 gr and 5000ppm respectively. It was used two types of surfactant; acid... 

Asphaltene, the heaviest and most polarizable fraction of crude oil, has a potential to precipitate, deposit and plug pipelines, causing considerable production costs. The main objective of this study is to contribute to the thermodynamic and transport modeling of asphaltene in order to predict its precipitation, segregation and deposition. Potential calculation of some thermophysical properties of asphaltene is also explored. Predicting the flow assurance issues caused by asphaltene requires the ability to model the phase behavior of asphaltene as a function of pressure, temperature and composition. It has been previously demonstrated that the Perturbed Chain form of Statistical Association... 

In this project, combination of PC-SAFT equation of state and friction theory was used for predicting the viscosity of reservoir fluid. Parameters of PC-SAFT and f-theory are available for pure components, but they are not known for oil cuts that are complex hydrocarbon mixtures. To solve this problem, in the first step, existing optimized parameters for PC-SAFT EOS of hydrocarbon mixtures were used and then, parameters of f-theory for mixtures were optimized. To set the parameters, two approaches were studied. The first approach is to obtain a series of empirical correlations that can estimate the parameters of f-theory (in conjunction with PC-SAFT) for oil cuts in terms of their molecular... 

In this research, the partitioning of Penicillin G-Acylase in aqueous two-phase systems (ATPS) containing poly ethylene glycol (PEG) 20000 or 35000 and potassium di-hydrogen phosphate (KH2PO4) or sodium citrate (C6H5Na3O7.5H2O) is measured at three temperature (301.2, 307.2 and 310.2) K. The effects of temperature, polymer molecular weight, polymer and salt concentrations on partitioning of Penicillin G in the aqueous two-phase systems are studied. The experimental data showed that composition of salt has a large effect on partitioning of Penicillin G in ATPS and temperature of system has small effect on the partitioning. The modified local composition model was used to obtain the activity... 

In tis study, 4 approaches were applied for estimating Minimum Miscibility Pressure (MMP). An oil sample from Norooz and Soroosh field has examined by means of association gas of foroozan field and Carbon Dioxide gas in experimental approach.the experimental method used for estimating MMP in Slim-tube. This kind method is applied in industry widely. The results indicate that the MMP of Carbon Dioxide and Norooz field oil is 3538 psi and with Soroosh field oil is 3650psi. the MMP of foroozan associated gas and Norooz field oil is 5643 psi and MMp with this gas and soroosh field oil not estimating  

In this study two approaches were applied to predict the hydrate dissociation pressure of natural gas in the presence of aqueous water. One approach applied van der Waals and Platteeuw solid solution theory & PR EOS the other applied a feed forward multi layers artificial neural network (ANN) with 19 input variables (temperature, existence of hydrocarbon liquid and ice phase, gas phase composition, inhibitor composition in aqueous phase), and one hidden layer with 17 neurons. In comparison of both methods it was concluded that, in temperature above 12℃ , ANN is more accurate than thermodynamic model, but in lower temperature thermodynamic model is comparable with ANN. The trained network... 

Catalytic reforming of naphtha is an important process to convert of low-octane number naphtha into high-octane number gasoline. Deactivation of catalysts, is the major problem for this process. In this study, catalytic reforming unit of Tabriz oil refinery investigated, and Smith’s kinetic model used for modeling. Also, several models presented for activity of catalysts. To find the parameters of presented models, the difference between the calculated and experimental values of outlet temperatures of each bed and aromatics, paraffin and naphthene yields simultaneously must be minimized. Using Genetic Algorithm Toolbox in Matlab software, optimization was performed and results indicated that... 

This project simulates the absorption of carbon dioxide absorbent on 4A zeolite is carried out using Monte Carlo simulation. VBA is a programming language and software used. Grand Canonical simulations performed on a set of particles (Grand Canonical) intended to present new algorithms and computational simulations are presented. Density fluctuations in the algorithms used and the smallest value of less than 0.2 is considered. In the new method of modeling, simulation node cell packing and moving is done on a given node. Adsorption density results obtained from the simulation carried out shows that the adsorption process is the logical and reasonable. Also, the part of the validation of the... 

In this project, theoretical and experimental study of methane adsorption on Multiwall Carbon Nano-Tubes (MWCNT) has been performed. This study has been conducted in the way to achieve a suitable method for methane storage and transportation. To carry out the experiments, the volumetric method was used up to 500 psia at various temperatures of 298.15 K, 303.15 K, 308.15 K. The effect of moisture was also studied at 298.15 K. Also, various adsorption isotherms were used to model the experimental data collected in this work. The results showed that the amount of methane adsorbed on the MWCNT can decrease with increasing the moisture and temperature of the adsorption cell. In order to... 

Many researchers were interested in gas hydrates because of their especial properties. These researches divided in two fields, thermodynamic and kinetic. The studies on first field began since many years ago, and they provided suitable results. But the investigation of hydrate formation kinetic started for 30 years ago, approximately, and according to its features such as high complexity of crystallization process and severe dependency on system, yet the comprehensive and pervasive model was not presented. At this project, after the presentation and survey of diverse models, in order to kinetic modeling of available data, among different kinetic models a reaction model selected. Then primary... 

In this work, PC-SAFT, an equation of state based on perturbation theory, is applied to predict the phase behavior of the reservoir fluids. PC-SAFT parameters for pure components are available but they cannot be calculated for petroleum fractions with unspecified components and composition. To solve this problem, and make use of the PC-SAFT model in the reservoir fluids simulations, two approaches are studied. In the first approach new correlations are developed which are able to predict the PC-SAFT parameters for plus fractions based on their molecular weight and mass density. The second approach is to use the artificial neural networks (ANNs) for estimation of PC-SAFT parameters for the... 

The Darcy’ law is valid for low velocity or low Reynolds number where merely viscous force is responsible for pressure loss in the porous media. At higher velocity, because of inertial forces and turbulency, the pressure loss would be higher than Darcy’ law estimates; therefore at these flow regimes the Darcy’ law is no longer valid. Hence, consideration of Non-Darcy flow effect is necessary to sufficiently model high gas velocity effects. The velocity is high in gas reservoirs especially those ones that are considered for underground gas storage. In this study, the effects of Non-Darcy flow on several parameters such as; estimation of differential pressure, flowing bottom hole pressure,... 

Transport of drilling cutting to the surface is the most important function of drilling fluid. Insufficient hole cleaning leads to accumulation of cuttings in the annulus especially of a Horizontal wellbore. This may cause severe drilling problems including reduction in rate of penetration, stuck pipe, premature bit wear, increase the mud lost, high drag and torque. In this research work a mathematical model is developed to simulate cutting transport process in the horizontal drilling wells. A three-layer model was used to simulate cutting transport process in horizontal wellbores: a stationary at the bottom of hole, a moving bed and a suspension layer on top of these layers. In this model,...