Sharif Digital Repository

The success of matrix acid production operations and its proper efficiency is one of the main challenges for oil and gas companies. The heterogeneity of the reservoir formation (especially the permeability difference) in the area around the well due to the presence of different reservoir layers results in the non-uniform distribution of acid among them and adds acidizing challenges. In order to improve production conditions, stimulation fluid transfer to the low permeability layer, which is the main target of acidizing. In this study, a new generation of chemical diverter, called Viscoelastic Surfactant, has been used. These materials have two components of elastic and viscous behavior, and... 

Fracture reservoirs are highly heterogeneous. This heterogeneity makes the process of adjusting model parameters to match both the static geological and dynamic production data challenging. For this reason, the characterization of the fracture network of these reservoirs, which is achieved by finding the appropriate probability distributions of the fracture properties in the discrete fracture network model, requires the use of an integrated workflow for the process of history-matching.This thesis, presents an integrated workflow for the process of history-matching of naturally fractured reservoirs with field-scale performance capability. In this methodology, first, multiple discrete fracture... 

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... 

Asphaltene deposition, considered as the heaviest and the most polarizable fraction of crude oil, can cause severe problems in oil production and extraction systems. Oil production companies annually bear huge reduction or even cessation in production and, in turn, costs due to asphaltene precipitation and deposition in wellbore or production tubings. To gain more and better insight into asphaltene formation in production systems, the conceptual investigation on the mechanisms of asphaltene adsorption and deposition on a solid surface is indispensable. In this study Asphaltene's particle adsorption and deposition onto the metal surface under the effect of flow is investigated by experimental... 

Acidizing is one of the most effective techniques to remove the formation damage and restore (or even increase) the permeability of the near wellbore region. Although this technique is widely used to resolve the skin problem, it could initiate new damages itself that hinder the fluid flow and decrease the well production, consequently. Acid-oil emulsion and sludge formation are known as two major induced formation damage and the main reasons for the oil well acid treatment failures.When the HCl is reacted with asphaltenic crude oil during matrix acidizing, it results in unexpected damage at the near wellbore region and hinder the fluid flow through certain mechanisms include:
1- Pore... 

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... 

The economic framework of the petroleum sector exhibits significant divergence from other businesses owing to the substantial risks and uncertainties inherent in oil and gas ventures, compounded by highly unpredictable price fluctuations. Moreover, the abundance of uncertainties in the data employed for investment decisions in petroleum projects is very large, thus exerting a significant impact on the decision-making processes. This research delves into the impact of diverse risk factors on oil contracts and scrutinizes their influence on contractual dynamics. The study unfolds in three segments, encompassing an examination of economic factors shaping oil contracts, model design, and the... 

Asphaltine particle precipitation may lead to serious problems in petroleum industry; including wellbore transmissibility reduction. One of the proposed remedial methods is to make a use of the microorganisms which are able to consume the heavy hydrocarbon chains.
Hydrophobicity of a cell surface is one of the parameters which greatly affect the microorganism adhesion to water insoluble hydrocarbons, in which results a higher hydrocarbon biodegradation. Consequently as the hydrophobicity of a cell surface increases; the microorganism tendency to bond with the hydrocarbon molecule enhances. The presence of a surface active agent, as an instance a chemical surfactant, will affect the... 

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... 

Quartz crystal microbalance (QCM) is a piezoelectric sensor used to measure the mass of adsorbent deposition at the nanoscale on the surface, real-time and non-destructively. The QCM technique has recently gained extensive attention in the chemical and oil industries and other research fields such as medicine and nanotechnology due to its various applications in the advanced sciences. This technique provides comprehensive insights to scientists in the field of phase equilibrium of low-solubility and solid-liquid interactions. Therefore, many attempts have been made to investigate the interaction phenomenon mechanistically using QCM.Scale formation can have many adverse effects, and... 

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... 

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-CO2 as well as crude oil-N2 systems at different temperatures and pressures. Moreover, minimum miscibility pressures (MMP) and first-contact miscibility pressures (Pmax) of crude oil/CO2 and crude oil/N2 systems at different temperature levels are determined by applying vanishing... 

To have a deeper understanding of Hydraulic fracturing operation, in this study four important parts in this field was developed and simulated. In the first part, continuity and momentum equations for a single phase flow in a propagating penny-shaped fracture inside an impermeable matrix was revisited based on a fixed coordinate system. Its correctness was validated against experimental data and its features were compared with the well-known lubrication theory in analytical form. The new derived continuity equation caused the fracture tip to have a positive and finite pressure while, the conventional model predicted negative infinity for that. In the second part, Finite Volume method was... 

The study of porous media, especially in pore-scales (micro and nano scales), is of particular importance in various sciences such as petroleum engineering, chemical, and civil engineering. Determine the physics of the pore scale to understand it better, identify the conditions for it to enforce the laws better, and explain some of the phenomena unknown so far, and finally obtain the parameters performed in the laboratory for specific samples are the main goals of these studies. One of the most well-known methods for analyzing porous media is pore network modeling. These models are always affected by the macroscopic structure of porous media, such as their multiscale state. In this study, an... 

Low salinity/smart waterflooding is simple to apply and a promising enhanced oil recovery method in which ion-tuned saltwater is injected into subsurface oil reservoirs. Many aspects of this operation, in particular those pertaining to nano-scale, are not yet fully understood. The present dissertation is an attempt to shed light on the microscopic properties and behavior of rock/brine/oil interfaces throughout low salinity/smart waterflooding. Several simulations were carried out for oil/brine and calcite/brine categories each containing various ions and hydrocarbons compounds. The surface contribution of non-functional oil compounds (aromatics and aliphatics) near brine medium was... 

About 20% of total oil in the world is reserved in fractured reservoirs and there is also more than 60% of remained oil in the world in these reservoirs. But increasing recovery factor and production from this type of reservoirs was not very successful. After water flooding process most of the oil remains in the reservoir. The amount of remained oil is much more specially in fractured reservoirs. Surfactant flooding in one of the well-known enhanced oil recovery methods for reduction of interfacial tension between fluids to decrease capillary forces that cause less oil trapping and higher oil recovery. But a comprehensive and accurate understanding of the mechanism of this process and...