Sharif Digital Repository

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... 

Nowadays, due to limitation of production from conventional oil reservoirs, enhanced recovery from heavy oil reservoirs is of great concern. However, production from these energy resources is not a simple task and production using common technologies is not easily exploitable. Heterogeneous structure and also high surface tension between injected fluid and reservoir oil are of the main challenges during water flooding processes in heavy oil reservoirs. The high surface tension force causes a large part of the oil remains in the reservoir after the water flooding operation. One method for overcoming this problem is the use of surfactants that reduces capillary forces and consequently... 

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... 

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... 

The purpose of this study was to investigate the experimental and modeling of the drop formation process on calcite rock and calcite aged in nano fluid surfaces in order to analyze size dependent contact angle and wettability modification. To do this, the calcite surfaces were prepared by cutting to an approximately size of 3*3*0.4 cm and grinded and polished to achieve different roughnesses. The purity and roughness of the samples were determined by X-ray diffraction and atomic force microscopy, respectively. In order to conduct the dynamic and static contact angle measurements on the calcite surface in vapor saturated condition, a small laboratory device was designed. The advanced contact... 

Nanoparticles can be applied as chemical agent in enhnaced oil recovery like surfactants and polymers. One of nanoparticles usefull capabilities is modification of their surface. This research investigates this capabilty of nanoparticles in enhanced oil recovery. Surface modification of nanoparticles with both agents can bring new abilities to these materials. Here surface of silica nanoparticles is modified by hydrophilic agent comprising PEG groups, hydrophobic agent comprising propyl group and both agents. FT-IR tests showed that grafting of modifiyng agents on surface of nanoparticles is well done. To investigate effect of nanoparticles surface modification on nanoparticles capability in... 

Recent studies in nanotechnology field have shown this technology could solve many challenges and needs in oil and gas industry. As yet, many applications of nanoparticles in enhanced oil recovery have been reported. One of the most important applications is wettability alteration due to presence of nanoparticles in injecting fluid, which has recently been studied by several research groups. These studies indicate that, presence of nanoparticles in injecting water would improve oil recovery. However, there is no adequate information about the mechanisms affecting fluid flow in reservoir rock and its mathematical modeling.The aim of this project is to evaluate the effect of injection of... 

In this research we aim to find enhance oil recovery mechanisms involved in nano-bio material injection by micro model apparatus which has not been studied before. Especially for injection in heavy oil and shaly porous media that forms most of heavy oil reservoirs. To this end, microscopic images from injection of nano-bio materials to shaly patterns have been taken and analyzed to find the process mechanism. Also amount of enhance oil recovery in different conditions like type of microbe forming bio material, nano-bio material concentration and type of flow pattern (shale characteristics including length, direction and distance from injection and production wells) will be studied.Three... 

There are considerable investigations on wettability alteration in carbonate reservoirs in recent years. The presence of ions including Ca, Si, Al etc in natural carbonate rocks and also the presence of various fatty acids, resins, asphaltenes etc in crude oil makes it difficult to understand the complex mechanism of wettability alteration by using surfactants. Furthermore there is still a conspicuous lack of dynamic wettability alteration model to demonstrate the dynamic behavior of cationic surfactants during wettability alteration. It is also widely accepted that cationic surfactants have substantial impact on changing the wettability of strongly oil-wet matrixes to a more water-wet... 

Recently, the researchers try to identify the application of nanofluids for wettability alteration. Changing the wettability of reservoirs, which gas injects to them, to gas wet can lead to enhanced oil recovery. Although several studies have been conducted to introduce proper nanofluids for altering the wettability of reservoirs to gas wet, there is not enough study to investigate the application of nanocomposites for wettability alteration of carbonate reservoirs. In this study, 20 nanoparticles with different compositional structures were synthesized, and then various nanofluids were prepared for the experimental survey. Also, the potential of these nanofluids for wettability alteration... 

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... 

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... 

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...