فهرست مطالب

Iranian Journal of Oil & Gas Science and Technology
Volume:3 Issue: 4, Autumn 2014

  • تاریخ انتشار: 1393/06/18
  • تعداد عناوین: 6
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  • Ehsan Rahmandoost, Behrooz Roozbehani *, Mohammad Hosein Maddahi Pages 1-15
    CO2 emissions from combustion flue gases have turned into a major factor in global warming. Post-combustion carbon capture (PCC) from industrial utility flue gases by reactive absorption can substantially reduce the emissions of the greenhouse gas CO2. To test a new solvent (AIT600) for this purpose, a small pilot plant was used. This paper presents the results of studies on chemical methods of absorbing CO2 from flue gases with the new solvent, and evaluates the effects of operating conditions on CO2 absorption efficiency. CO2 removal rate of the AIT600 solvent was higher in comparison to the conventional monoethanolamine (MEA) solvent. The optimized temperature of the absorber column was 60 °C for CO2 absorption in this pilot plant. The overall absorption rate (Φ) and the volumetric overall mass transfer coefficient (KGaV) were also investigated.
    Keywords: Operating conditions, CO2, Air Flow Rate, Chemical Absorption, Efficiency
  • Parastoo Bagheri, Sina Sodagar *, Gholamreza Rashed, Amin Yaghootian Pages 16-25
    Time-of-flight diffraction method (ToFD) is an amplitude-independent sizing method which is based on the measurement of time-of-flight of defect tip diffracted waves. Although ToFD can measure through-wall length of defect accurately, this method is not capable of measuring horizontal defect size. In this paper, a new ToFD method for evaluating horizontal planar defects is presented. The finite element method (FEM), using the ABAQUS software package, is employed to simulate the ultrasonic wave behavior in the test blocks and its interaction with the embedded planar defects. The phased array technology is also used to model the ultrasonic inspection system parameters. FEM simulation of the new ToFD method for different crack sizes shows that, compared to the conventional ToFD method, the accuracy of results is within acceptable range to use the novel technique for measuring the horizontal planar defects.
    Keywords: Ultrasonic Wave, Diffracted Wave, Horizontal Planar Defects, ToFD
  • Jaber Esmaeeli Azadgoleh, Riyaz Kharrat*, Nasim Barati, Ameneh Sobhani Pages 26-40
    Nanotechnology has various applications in oil and gas industry such as enhanced oil recovery (EOR). The main challenge in using nanoparticles in EOR processes is their stability in harsh conditions such as high temperature, high pressure, and intermediate to high salinity. However, most of the recent experimental works have been performed under unrealistic conditions such as the use of distilled water as the injected fluid and room temperature. The main objective of this work is to study the effect of these factors on the stability of nanoparticle dispersions through several methods such as direct observation, optical absorption measurement, and nanoparticle effective diameter in different periods of time. The critical salt concentration (CSC) was determined for two kinds of monovalent electrolytes in various particle concentrations and temperatures. The results have shown that CSC for potassium chloride (KCl) is less than sodium chloride (NaCl) and it decreases as nanoparticle concentration and temperature increase. Moreover, the influence of two types of surfactants on the stability of silica dispersions was studied and the results revealed that an anionic surfactant increases the CSC, while a nonionic surfactant leads to the instability of dispersion even at low electrolyte concentrations.
    Keywords: Silica nanoparticle, Dispersion stability, temperature, Salinity, Surfactant
  • Maryam Ghorbani, Mohammad Reza Khorsand*, Mohsen Masihi Pages 41-54
    The performance of water flooding can be investigated by using either detail numerical modeling or simulation, or simply through the analytical Buckley-Leverett (BL) model. The Buckley-Leverett analytical technique can be applied to one-dimensional homogeneous systems. In this paper, the impact of heterogeneity on water flooding performance and fractional flow curve is investigated. First, a base one-dimensional numerical model is considered and then the numerical model is made and validated through comparison with the Buckley-Leverett fractional flow equation. Then, the model is extended to two dimensions and heterogeneity is incorporated in the modeling by using six different heterogeneous models. In particular, distributions for permeability values are considered. Fractional flow curves and water flooding performances are investigated for each individual model. A modification in the Buckley-Leverett fractional flow equation is discussed in order to consider the heterogeneity effects.
    Keywords: Water flooding, Buckley, Leverett, Fractional Flow, Saturation Distribution, Numerical modeling
  • Seyed Shamsollah Noorbakhsh, Mohammad Reza Rasaei *, Ali Heydarian, Hamed Behnaman Pages 55-66
    Reservoir models with many grid blocks suffer from long run time; it is hence important to deliberate a method to remedy this drawback. Usual upscaling methods are proved to fail to reproduce fine grid model behaviors in coarse grid models in well proximity. This is attributed to rapid pressure changes in the near-well region. Standard permeability upscaling methods are limited to systems with linear pressure changes; therefore, special near-well upscaling approaches based on the well index concept are proposed for these regions with non-linear pressure profile. No general rule is available to calculate the proper well index in different heterogeneity patterns and coarsening levels. In this paper, the available near-well upscaling methods are investigated for homogeneous and heterogeneous permeability models at different coarsening levels. It is observed that the existing well index methods have limited success in reproducing the well flow and pressure behavior of the reference fine grid models as the heterogeneity or coarsening level increases. Coarse-scale well indexes are determined such that fine and coarse scale results for pressure are in agreement. Both vertical and horizontal wells are investigated and, for the case of vertical homogeneous wells, a linear relationship between the default (Peaceman) well index and the true (matched) well index is obtained, which considerably reduces the error of the Peaceman well index. For the case of heterogeneous vertical wells, a multiplier remedies the error. Similar results are obtained for horizontal wells (both heterogeneous and homogeneous models).
    Keywords: Near, well Permeability Upscaling, Heterogeneity, Peaceman Well Index, Single Phase Upscaling
  • Azizollah Khormali, Dmitry Gennadievich Petrakov*, Georgy Yuryevich Shcherbakov Pages 67-77
    A fundamental study of scale formation of calcium carbonate (CaCO3) for producing oil wells has been carried out. This article presents the study of the prediction of salt deposition in two different synthetic formation waters and investigates the effects of temperature and pressure on calcium carbonate precipitation. The dependence of the induction period of the precipitation of calcium carbonate on the concentration of calcium ions was studied. In order to study the chemical scale inhibition, the most effective inhibitors, which are based on the risk analysis of scaling and laboratory reagent selection, were examined for evaluating the performance of salt inhibition. In this work, a new multi-component inhibitor was made and its scale effectiveness was evaluated at different concentrations. The developed inhibitor was mixed with other inhibitors to prevent calcium carbonate precipitation. The observations showed the synergetic inhibition effect on the scale inhibition at different concentrations of scale inhibitors. The new inhibitor provided high scale effectiveness at specific concentrations and low corrosion activity.
    Keywords: Calcium carbonate, Corrosiveness, Induction Period, Scale Inhibition, Synergetic Effect