Sharif Digital Repository

During production from gas condensate reservoirs, reservoir pressure decreses to lower than dew point pressure of the reservoir fluid. Consequently, condensates will form in near wellbore regions, which significantly decrease well productivity. One of the remediations that is recently proposed for solving this problem is wettability alteration of near wellbore region to gas wetting condition. In comparison to other methods, it provides a better permanency, which is its key advantage. The main purpose of this thesis is, quantitative, qualitative and modeling study of wettability alteration of rock to gas wetting condition and verification of modeling rsults for a reservoir rock sample. Also,... 

Gravity drainage is the self-propulsion of oil downward in the reservoir rock. Under favorable natural and operational conditions, it has been found to effect recoveries comparable to water displacement. With modern technical knowledge, the operator can often make a choice between dissolved gas drive, water drive and gravity drainage as the principal recovery agent in a reservoir. So far, gravity drainage has received less consideration than the other two. Gravity drainage is one of the most important processes taking place in fractured reservoirs and it plays a major role in oil recovery from low permeability matrix blocks during gas injection process. Gravity drainage is responsible for... 

The discrete fracture network and continuous fracture network are among the most widely used methods to model naturally fractured reservoirs. Each method faces particular limitations. The recently introduced recovery curve method (RCM) is believed to meet the limitations of the common methods. In the RCM the recovery curves are used to more realistically describe matrix-fracture interactions. It is necessary to present appropriate solutions to apply the RCM in the real fileds and also to evaluate it based on the historical production data. In this work at first, the basics of the RCM are presented then with a simple column model this method is validated. Then in a column model and a field... 

One of the most important production mechanisms of fractured reservoirs is wettability alteration. Since most fractured reservoirs are carbonate, and thus are often oil-wet; production of these reservoirs is facing their special challenges. Since most of our country reservoirs are fractured carbonate type, determination of the exact mechanisms of their production is necessary. Thermal EOR methods traditionally have been welcomed by big oil companies. Also, these methods of enhanced oil recovery techniques, have a much greater share in the production history of all EOR methods, rather than other EOR methods. Exponentially decreasing of oil viscosity on heating, is the main reason for using... 

One of the most common methods for determining elastic moduli of rocks and porosity is acoustic velocity log. The elastic moduli of reservoir rock are widely used in geomechanical modelling, borehole stability and hydraulic fracture design. Carbonate oil reservoirs are known for heterogeneity and anisotropic nature. Therefore correlation of acoustic velocity and rock properties are generally challenging. Rock’s shear modulus is very important during saturating of sample with pore fluid because assumed it is independent of pore fluid type. However due to the several fluid-solid interaction mechanisms such as velocity dispersion, surface energy reduction and viscous coupling, shear modulus... 

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... 

In recent years, application of silica nanoparticles for wettability alteration of reservoir rocks as an effective approach in enhancing oil recovery from petroleum reservoirs is introduced. However, in this area, lack of fundamental studies to provide a clear understanding about the interaction between these nanoparticles and carbonate rocks (as the predominant reservoir rocks in the world and Iran), which is of particular importance, is sensed. Therefore, the main purpose of this dissertation is to present a mechanistic investigation about the interaction of silica nanoparticles (the most used nanoparticles) with carbonate rock from theoretical and experimental viewpoints. To better... 

increased cohesion up to 4H pencil. Results of immersion test in water showed stability of coatings. Polarization test in naphtha and water mixture for stainless steel, copper and aluminum meshes demonstrated 98.89%, 86.25% and 66.6% protection efficiency respectively. In order to study of oil and water separation efficiency, mixtures of water and naphtha with different content of naphtha were used. Separation test for 200μm St.St mesh in different slopes demonstrated that changing of slop increase separation efficiency up to 95.5% for water and up to 100% for naphtha. Separation test for meshes with different pore size demonstrated that meshes with small pore size are more appropriate for... 

During all operations in oil and gas reservoirs, it is possible to cause formation damage. These damages can greatly reduce the rate of production. One of the major damages that can seriously affect the performance of a reservoir is the damage caused by drilling fluid. The main purpose of this thesis is to study the main mechanisms of formation damage caused by water-based drilling fluid using a glass micromodel for the first time. An accurate understanding of the mechanisms of formation damage can provide a good understanding of the selection of the type and concentration of materials used, as well as appropriate methods to control and eliminate damages. for controlling the drilling fluid... 

Oil and gas reservoirs in various parts of the world have declined over time, despite a high percentage of oil. Due to the increasing need for hydrocarbon resources, the need for more cost-efficient harvesting methods and less environmental damage is felt. Injection of saline water is one of the most cost-effective ways of harvesting due to the need for no expensive additives. On the other hand, microscopic glass modeling can be used to better understand and understand the performance of saline water at the microscopic scale. In this study we have been able to visualize the effective factors in infusion of saline water. Improved interfacial tensile and particle migration in kaolin-coated... 

The Low salinity water flooding is one of the important methods of secondary and tertiary oil production in which many expert petroleum-production engineering working on it in recent two decades. There are some basis mechanisms for low salinity method presented in the literatures including fine migrations, alkaline flooding, multicomponent ionic exchange, electrical double-layer expansion and pH-driven wettability alteration. The main approach is generating low salinity mechanism especially wettability alteration in OpenPNM framework. OpenPNM is a python base framework developed by Jeff Gostick for porous media modeling. OpenPNM has paved the way for extracting pore network models (PNM) from... 

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... 

Many of oil reservoirs in Iran that are fractured, do not have high Recovery Factor (RF), therefor Enhanced Oil Recovery (EOR) methods are exerted in them. In fractured reservoirs, due to high capillary pressure in matrix and low amount of it in fracture, the wetting phase tends to imbibe to the matrix from the fracture. Altering the wettability of reservoir rock from Oil-Wet (OW) to Water-Wet (WW) enables the injected water to imbibe to matrix and sweep its oil. Also reducing oil/water IFT turns oil to small droplets, helps them to pass narrow pores and be produced. In one of the new EOR methods called chemical EOR, chemical additives are injected to the reservoirs along with water to... 

Enhanced Oil Recovery (EOR) techniques have become of the main priorities of the oil industry during the high oil price era. It is interesting to note that the common method to increase production from reservoirs is the water injection method, which recovers a very low amount of oil from the oil-wet matrices due to the lack of water imbibition. Previous studies have shown that changing the wettability of rock would critically increase the oil recovery efficiency. This could be achieved by the low-salinity water injection method. In recent years, extensive studies have been conducted on this technique to evaluate its effectiveness for various types of oil reservoirs. Simultaneous injection... 

Low salinity water flooding (LSWF) is one of the enhanced oil recovery (EOR) methods that can be applied in both secondary and tertiary recovery techniques. Some reports indicate no incremental oil recovery associated with this method, and the reason can be associated with the binary and tertiary interactions between oil-brine-rock (OBR) systems. In some OBRs, the initial conditions are not favourable in terms of initial wettability. One of the key factors is the local rock heterogeneities in permeability and mineralogy which can affect LSWF performance because the microscopic and macroscopic heterogeneities can impact the flow pattern of the injected water, oil displacement efficiency, and... 

Based on numerous laboratory and field evidence, low-salinity waterflooding or engineered salinity waterflooding can lead to enhanced oil production. According to the literature, the mechanisms involved in this process can be divided into two general categories: fluid-fluid interactions and solid-liquid interactions. These mechanisms are caused by intermolecular and electrostatic forces at the rock and fluid interfaces. The most important controlling factor of the electrostatic forces is the concentration of ions at/near fluids-rock interface. Therefore, improving the concentration of ions causes a shift in wettability toward a more water-wetting state, eventually leading to increased oil... 

As fossil fuels are still the world's most important source of energy, as well as the maturity of most of the world's oil reservoirs, there is a need for enhanced oil recovery methods to meet the world's increasing oil demands. MEOR methods are new and promising methods that are still in the research and development stage. One of the MEOR methods is the use of biosurfactants, which increase the oil recovery by two mechanisms: 1) reducing the interfacial tension between water and oil and 2) changing the wettability of the rock. In this study, the performance of two glycolipid biosurfactants, rhamnolipid and sophorolipid, in increasing oil recovery has been investigated. Initially, surface... 

The present thesis investigates the micro-droplet dynamics in an inclined channel covered with flexible structures. For this purpose, the DPD (dissipative particle dynamics) method is used to study the behavior of particles present in the flow, including the droplet, the fluid around the droplet, and polymeric structures. This model leads to a more accurate representation of flow hydrodynamics and indicates the way for exploring and understanding complex fluid properties in real flows. The first part of the thesis deals with the dynamics of rising bubbles attached to a vertical wall under different wettability conditions. Even though bubbles rising freely in a liquid have extensively been... 

Hydrogen storage in porous subsurface formations, such as aquifers or depleted hydrocarbon reservoirs because of their high storage capacity, has gained momentum as a promising approach to balance the renewable energy supply and demand. However, the poor understanding of hydrogen flow dynamics in porous media is the main obstacle to the development and widespread application of underground hydrogen storage (UHS). For example, the main uncertainty is lack of detailed understanding of hydrogen flow dynamics in the natural porous media which leads to the unknown volume of recoverable hydrogen for this cyclic process. In this research, by developing a visual microfluidic apparatus to handle...