Current Issue

Advanced NanoMaterials and Technologies for Energy Sector – AdvNanoEnergy 2019; Vol 3; Issue 2

Asphaltene precipitation is an important phenomenon faced during oil production that causes many problems such as plugging the reservoirs, production wells, and transmission pipelines. Therefore, it is necessary to predict the asphaltene precipitated as a function of temperature and pressure. The aim of this study is to investigate the effect of pressure and temperature on the asphaltene precipitation in an Iranian oil reservoir. For this reservoir, the heaviest component is splitted and regrouped with a Commercial PVT Modelling Software. The new heaviest component is divided into precipitating and non-precipitating components. An equation of state (EOS) is tuned by using experimental data including constant composition expansion (CCE), differential liberation (DL) and separator tests. The results of the stability analysis show that there is a high risk of asphaltene precipitation in this reservoir. The maximum amount of asphaltene precipitation occurs around the saturation pressure. It is also observed that asphaltene precipitation is increased by decreasing the temperature along the production wells and transmission pipe-lines.

 

Local electric fields are appeared in dielectric and semiconductors due to the destruction of symmetry, creating the vacancies, point defects and chemical impurities in material. By increasing in external electric field value there are numerous structural changes will be generated. Some of them will produce such great local fields that will destroy all material or change its physical properties. The studying the nature of local electric fields will open new tendency in electronic device producing, from one side, and, help to change materials’ properties according to our needs, from another side. Point defects in silicon films were characterized by using electron-paramagnetic resonance spectroscopy and laser picoseconds spectroscopy. Coupling two dangling bonds are transformed into A defect with coupling bonds by the following way according to Elsner theorem of matrix perturbation theory. The crystal phase destruction in nanocrystalline silicon film by applying external electric field was investigated by Raman spectroscopy. The possible mechanism of phase destruction was proposed.