فهرست مطالب

Iranian Journal of Oil & Gas Science and Technology
Volume:6 Issue: 1, Winter 2017

  • تاریخ انتشار: 1396/01/21
  • تعداد عناوین: 5
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  • Mohammad Saki, Ali Reza Khazal Pages 1-12
    The chemical surfactant flooding can mobilize the trapped oil by lowering the interfacial tension between oil and brine and in some cases altering the reservoir rock wettability. In this work, the effect of surfactants on oil/brine interfacial tension was experimentally investigated. First, the effect of surfactants concentration was surveyed. Afterwards, the effect of salinity on surfactant behavior was studied. The experiments were carried out at ambient and reservoir temperatures (all at reservoir pressure) to clarify that we cannot generalize the ambient experimental results to reservoir ones and the experiments must be done in reservoir conditions to attain more certainty. Sodium dodecyl sulfonate, cetyl trimethyl ammonium bromide and Triton X-100 were used as the surfactants. The oil and brine samples of the Iranian Asmari reservoir were used. Pendant drop method was used to measure oil/brine interfacial tension. Based on the results, it is concluded that the anionic surfactant (SDS) has a better performance at reservoir and ambient temperatures. The superiority of SDS is more emphatic at reservoir temperature than ambient temperature. At reservoir temperature, the SDS solution lowers the interfacial tension significantly (0.4 mN/m) even when a very low concentration of SDS (0.04 wt.%) is added to brine.
    Keywords: Surfactant, CTAB, SDS, Optimum Salinity, IFT
  • Seyed Ali Hosseini, Sirus Nouri, Sajad Hashemi, Mansor Akbari Pages 13-25
    The removal of sulfur compounds from petroleum is extremely necessary for industrial and environmental reasons. Sulfur in transportation fuels is a major air pollution source. In this work, the efficiency of nanostructured Ni-clinoptilolite adsorbent was investigated in the removal of sulfur from gas oil. For this purpose, the design of experiments was performed by selecting effective factors in desulfurization process. Response surface methodology was selected to model the desulfurization process. Ni-containing nanoadsorbents were prepared by a wet-impregnation method. Gas oil model containing 300 ppmW [M. N.1] sulfur was prepared by dissolving a calculated amount of dibenzothiophene (DBT) in n-decane. The concentration of DBT in n-decane was determined by UV-Visible spectrophotometer. The results revealed that sulfur removal extremely depended on the amount of metal and the nature of both metal and support. 5% Ni/support adsorbent resulted in higher sulfur removal efficiency. The optimum ratio of H2O2 to gas oil in the studied conditions was in the range of 5% (v/v) and 240 minutes for the best desulfurization performance during the process.
    Keywords: Desulfurization, Clinoptilolite, Nickel Supported Nanoadsorbent, Response surface methodology, Optimization
  • Masoumeh Bashiri, Mosayyeb Kamari, Ghassem Zargar Pages 45-62
    Water saturation and cation exchange capacity are the most significant parameters used to calculate a hydrocarbon zone potential. In clean formations, by applying the famous Archie model, which assumes that in the formation the only electric conductor is the formation water, the water saturation can be calculated. Additionally, in shaly sand formations this assumption may not be true as the ions are associated with clay minerals and transport electricity.
    We attempt to utilize some logs, as well as experimental data, to improve the water saturation calculations and the cation exchange capacity within shaly sand layers for an Iranian oil field. Therefore, several shaly sand models were considered for the calculations of these values for three wells of the Ahvaz oil field. The validity of the different models was controlled through the measured values of cation exchange capacity and water saturation on core samples. The comparative results show that cation exchange capacity and water saturation calculated using Ipek-Bassiouni model are more indicative of zone hydrocarbon potential with correlation coefficients of 0.91 and 0.95 respectively. The results of this study show the requirement for the I-B model in studied reservoir and its superiority compared to other models because it is on the basis of principles reflecting the formation water and clay counter ions conductive behavior.
    Concerning to this model, two cement exponents are incorporated to illustrate the electric current path tortuosity in clay bound water and free water. In the current work, cementation exponent in free water (mf) and clay bound water (mc) were estimated from pure shale and clean sand respectively. The results of this study are promising and can be simply extended in other similar neighboring shaly sand reservoirs.
    Keywords: Shaly Sand Reservoir, Water Saturation, Cation Exchange Capacity (CEC), Cement Exponent, Clay Bound Water
  • Mohammadreza Shishesaz, Davood Jafari, Davood Zaarei, Iman Danaee Pages 63-76
    Different amounts of nanoclay were incorporated into the acrylic resin matrix at 0, 1, 3, and 5 wt.% loadings. The coatings were applied on low carbon steel plates. Optical microscopy, sedimentation test, transmission electron microscopy, and X-ray diffraction were employed to investigate the dispersion of nanoclay in matrix. The corrosion resistance of coatings was evaluated by electrochemical impedance spectroscopy, polarization measurement, and salt spray test. In addition, pull-off and cross-cut tests were used for the assessment of coating adhesion to the substrate. The results indicated that the anti-corrosive properties of the acrylic resin were obviously increased by the addition of nanoclay. The nanocomposite coatings containing 3 wt.% clay showed the best corrosion resistance. Finally, the nanocomposites containing 1 and 3 wt.% showed the highest adhesion to the substrate.
    Keywords: Nanocomposite Coating, Montmorillonite, Corrosion, Impedance, Salt spray
  • Hamidreza Mousavi, Mehdi Shahbazian, Nosrat Moradi Pages 77-92
    Recently different approaches have been developed in the field of sensor fault diagnostics based on Auto-Associative Neural Network (AANN). In this paper we present a novel algorithm called Self reconstructing Auto-Associative Neural Network (S-AANN) which is able to detect and isolate single faulty sensor via reconstruction. We have also extended the algorithm to be applicable in multiple fault conditions. The algorithm uses a calibration model based on AANN. AANN can reconstruct the faulty sensor using non-faulty sensors due to correlation between the process variables, and mean of the difference between reconstructed and original data determines which sensors are faulty. The algorithms are tested on a Dimerization process. The simulation results show that the S-AANN can isolate multiple faulty sensors with low computational time that make the algorithm appropriate candidate for online applications.
    Keywords: Sensor Fault, Fault Isolation, Reconstruction Algorithm, Auto-Associative Neural Networks, multiple faults